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1. Constraining the Dense Matter Equation of State with New NICER Mass–Radius Measurements and New Chiral Effective Field Theory Inputs

Author

Nathan Rutherford, Melissa Mendes, Isak Svensson, Achim Schwenk, Anna L. Watts, Kai Hebeler, Jonas Keller, Chanda Prescod-Weinstein, Devarshi Choudhury, Geert Raaijmakers, Tuomo Salmi, Patrick Timmerman, Serena Vinciguerra, Sebastien Guillot, and James M. Lattimer

Subjects
Gravitational wave sources, Neutron stars, Neutron star cores, X-ray sources, Nuclear astrophysics, Astrophysics, QB460-466
Abstract

Pulse profile modeling of X-ray data from the Neutron Star Interior Composition Explorer is now enabling precision inference of neutron star mass and radius. Combined with nuclear physics constraints from chiral effective field theory ( χ EFT), and masses and tidal deformabilities inferred from gravitational-wave detections of binary neutron star mergers, this has led to a steady improvement in our understanding of the dense matter equation of state (EOS). Here, we consider the impact of several new results: the radius measurement for the 1.42 M _⊙ pulsar PSR J0437−4715 presented by Choudhury et al., updates to the masses and radii of PSR J0740+6620 and PSR J0030+0451, and new χ EFT results for neutron star matter up to 1.5 times nuclear saturation density. Using two different high-density EOS extensions—a piecewise-polytropic (PP) model and a model based on the speed of sound in a neutron star (CS)—we find the radius of a 1.4 M _⊙ (2.0 M _⊙ ) neutron star to be constrained to the 95% credible ranges ${12.28}_{-0.76}^{+0.50}$ km ( ${12.33}_{-1.34}^{+0.70}$ km) for the PP model and ${12.01}_{-0.75}^{+0.56}$ km ( ${11.55}_{-1.09}^{+0.94}$ km) for the CS model. The maximum neutron star mass is predicted to be ${2.15}_{-0.16}^{+0.14}$ M _⊙ and ${2.08}_{-0.16}^{+0.28}$ M _⊙ for the PP and CS models, respectively. We explore the sensitivity of our results to different orders and different densities up to which χ EFT is used, and show how the astrophysical observations provide constraints for the pressure at intermediate densities. Moreover, we investigate the difference R _2.0 − R _1.4 of the radius of 2 M _⊙ and 1.4 M _⊙ neutron stars within our EOS inference.

Published
2024
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2. Associations between baseline characteristics, CD4 cell count response and virological failure on first-line efavirenz + tenofovir + emtricitabine for HIV

Author

Oliver T. Stirrup, Caroline A. Sabin, Andrew N. Phillips, Ian Williams, Duncan Churchill, Anna Tostevin, Teresa Hill, David T. Dunn, David Asboe, Anton Pozniak, Patricia Cane, David Chadwick, Duncan Clark, Simon Collins, Valerie Delpech, Samuel Douthwaite, David Dunn, Esther Fearnhill, Kholoud Porter, Oliver Stirrup, Christophe Fraser, Anna Maria Geretti, Rory Gunson, Antony Hale, Stéphane Hué, Linda Lazarus, Andrew Leigh-Brown, Tamyo Mbisa, Nicola Mackie, Chloe Orkin, Eleni Nastouli, Deenan Pillay, Andrew Phillips, Caroline Sabin, Erasmus Smit, Kate Templeton, Peter Tilston, Erik Volz, Hongyi Zhang, Keith Fairbrother, Justine Dawkins, Siobhan O’Shea, Jane Mullen, Alison Cox, Richard Tandy, Tracy Fawcett, Mark Hopkins, Clare Booth, Lynne Renwick, Matthias L. Schmid, Brendan Payne, Jonathan Hubb, Simon Dustan, Stuart Kirk, Amanda Bradley-Stewart, Sophie Jose, Alicia Thornton, Susie Huntington, Adam Glabay, Shaadi Shidfar, Janet Lynch, James Hand, Carl de Souza, Nicky Perry, Stuart Tilbury, Elaney Youssef, Brian Gazzard, Mark Nelson, Tracey Mabika, Sundhiya Mandalia, Jane Anderson, Sajid Munshi, Frank Post, Ade Adefisan, Chris Taylor, Zachary Gleisner, Fowzia Ibrahim, Lucy Campbell, Kirsty Baillie, Richard Gilson, Nataliya Brima, Jonathan Ainsworth, Achim Schwenk, Sheila Miller, Chris Wood, Margaret Johnson, Mike Youle, Fiona Lampe, Colette Smith, Rob Tsintas, Clinton Chaloner, Samantha Hutchinson, John Walsh, Nicky Mackie, Alan Winston, Jonathan Weber, Farhan Ramzan, Mark Carder, Clifford Leen, Alan Wilson, Sheila Morris, Mark Gompels, Sue Allan, Adrian Palfreeman, Adam Lewszuk, Stephen Kegg, Akin Faleye, Victoria Ogunbiyi, Sue Mitchell, Phillip Hay, Christian Kemble, Fabiola Martin, Sarah Russell-Sharpe, Janet Gravely, Sris Allan, Andrew Harte, Anjum Tariq, Hazel Spencer, Ron Jones, Jillian Pritchard, Shirley Cumming, Claire Atkinson, Dushyant Mital, Veronica Edgell, Juli Allen, Andy Ustianowski, Cynthia Murphy, Ilise Gunder, Roy Trevelion, and Abdel Babiker

Subjects
antiretroviral therapy, ART, drug resistance, HIV, NNRTI, NRTI, Microbiology, QR1-502, Public aspects of medicine, RA1-1270
Abstract

Objectives: The aim of this study was to investigate associations between baseline characteristics and CD4 cell count response on first-line antiretroviral therapy and risk of virological failure (VF) with or without drug resistance. Methods: We conducted an analysis of UK Collaborative HIV Cohort data linked to the UK HIV Drug Resistance Database. Inclusion criteria were viral sequence showing no resistance prior to initiation of first-line efavirenz + tenofovir disoproxil fumarate + emtricitabine and virological suppression within 6 months. Outcomes of VF (≥200 copies/mL) with or without drug resistance were assessed using a competing risks approach fitted jointly with a model for CD4 cell count recovery. Hazard ratios for each VF outcome were estimated for baseline CD4 cell count and viral load and characteristics of CD4 cell count response using latent variables on a standard normal scale. Results: A total of 3640 people were included with 338 VF events; corresponding viral sequences were available in 134 with ≥1 resistance mutation in 36. VF with resistance was associated with lower baseline CD4 (0.30, 0.09–0.62), lower CD4 recovery (0.04, 0.00–0.17) and higher CD4 variability (4.40, 1.22–12.68). A different pattern of associations was observed for VF without resistance, but the strength of these results was less consistent across sensitivity analyses. Cumulative incidence of VF with resistance was estimated to be >2% at 3 years for baseline CD4 ≥350 cells/μL. Conclusion: Lower baseline CD4 cell count and suboptimal CD4 recovery are associated with VF with drug resistance. People with low CD4 cell count before ART or with suboptimal CD4 recovery on treatment should be a priority for regimens with high genetic barrier to resistance.

Published
2019
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3. Chiral power counting of one- and two-body currents in direct detection of dark matter

Author

Martin Hoferichter, Philipp Klos, and Achim Schwenk

Subjects
Physics, QC1-999
Abstract

We present a common chiral power-counting scheme for vector, axial-vector, scalar, and pseudoscalar WIMP–nucleon interactions, and derive all one- and two-body currents up to third order in the chiral expansion. Matching our amplitudes to non-relativistic effective field theory, we find that chiral symmetry predicts a hierarchy amongst the non-relativistic operators. Moreover, we identify interaction channels where two-body currents that previously have not been accounted for become relevant. Keywords: Dark matter, WIMPs, Chiral Lagrangians

Published
2015
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4. Lower healthcare costs associated with the use of a single-pill ARV regimen in the UK, 2004-2008.

Author

Eduard J Beck, Sundhiya Mandalia, Roshni Sangha, Mike Youle, Ray Brettle, Mark Gompels, Margaret Johnson, Anton Pozniak, Achim Schwenk, Stephen Taylor, John Walsh, Ed Wilkins, Ian Williams, Brian Gazzard, and NPMS-HHC Steering Group

Subjects
Medicine, Science
Abstract

AimInvestigate the cost and effects of a single-pill versus two- or three pill first-line antiretroviral combinations in reducing viral load, increasing CD4 counts, and first-line failure rate associated with respective regimens at 6 and 12 months.MethodsPatients on first-line TDF+3TC+EFV, TDF+FTC+EFV, Truvada®+EFV or Atripla® between 1996-2008 were identified and viral load and CD4 counts measured at baseline, six and twelve months respectively. Factors that independently predicted treatment failure at six and twelve months were derived using multivariate Cox's proportional hazard regression analyses. Use and cost of hospital services were calculated at six and twelve months respectively.ResultsAll regimens reduced viral load to below the limit of detection and CD4 counts increased to similar levels at six and twelve months for all treatment regimens. No statistically significant differences were observed for rate of treatment failure at six and twelve months. People on Atripla® generated lower healthcare costs for non-AIDS patients at £5,340 (£5,254 to £5,426) per patient-semester and £9,821 (£9,719 to £9,924) per patient-year that was £1,344 (95%CI £1,222 to £1,465) less per patient-semester and £1,954 (95%CI £1,801 to £2,107) less per patient-year compared with Truvada®+EFV; healthcare costs for AIDS patients were similar across all regimens.ConclusionThe single pill regimen is as effective as the two- and three-pill regimens of the same drugs, but if started as first-line induction therapy there would be a 20% savings on healthcare costs at six and 17% of costs at twelve months compared with Truvada®+EFV, that generated the next lowest costs.

Published
2012
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5. The cost-effectiveness of early access to HIV services and starting cART in the UK 1996-2008.

Author

Eduard J Beck, Sundhiya Mandalia, Roshni Sangha, Peter Sharott, Mike Youle, Guy Baily, Ray Brettle, Mark Gompels, Margaret Johnson, Brendan McCarron, Ed Ong, Anton Pozniak, Achim Schwenk, Stephen Taylor, John Walsh, Ed Wilkins, Ian Williams, Brian Gazzard, and NPMS-HHC Steering Group

Subjects
Medicine, Science
Abstract

To calculate use, cost and cost-effectiveness of people living with HIV (PLHIV) starting routine treatment and care before starting combination antiretroviral therapy (cART) and PLHIV starting first-line 2NRTIs+NNRTI or 2NRTIs+PI(boosted), comparing PLHIV with CD4≤200 cells/mm3 and CD4>200 cells/mm3. Few studies have calculated the use, cost and cost-effectiveness of routine treatment and care before starting cART and starting cART above and below CD4 200 cells/mm3.Use, costs and cost-effectiveness were calculated for PLHIV in routine pre-cART and starting first-line cART, comparing CD4≤200 cells/mm3 with CD4>200 cells/mm3 (2008 UK prices).cART naïve patients CD4≤200 cells/mm3 had an annual cost of £6,407 (95%CI £6,382 to £6,425) PPY compared with £2,758 (95%CI £2,752 to £2,761) PPY for those with CD4>200 cells/mm3; cost per life year gained of pre-cART treatment and care for those with CD4>200 cells/mm3 was £1,776 (cost-saving to £2,752). Annual cost for starting 2NRTIs+NNRTI or 2NRTIs+PI(boosted) with CD4≤200 cells/mm3 was £12,812 (95%CI £12,685-£12,937) compared with £10,478 (95%CI £10,376-£10,581) for PLHIV with CD4>200 cells/mm3. Cost per additional life-year gained on first-line therapy for those with CD4>200 cells/mm3 was £4639 (£3,967 to £2,960).PLHIV starting to use HIV services before CD4≤200 cells/mm3 is cost-effective and enables them to be monitored so they start cART with a CD4>200 cells/mm3, which results in better outcomes and is cost-effective. However, 25% of PLHIV accessing services continue to present with CD4≤200 cells/mm3. This highlights the need to investigate the cost-effectiveness of testing and early treatment programs for key populations in the UK.

Published
2011
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6. CD4 counts and the risk of systemic non-Hodgkin’s lymphoma in individuals with HIV in the UK

Author

Mark Bower, Martin Fisher, Teresa Hill, Iain Reeves, John Walsh, Chloe Orkin, Andrew N. Phillips, Loveleen Bansi, Richard Gilson, Philippa Easterbrook, Margaret Johnson, Brian Gazzard, Clifford Leen, Deenan Pillay, Achim Schwenk, Jane Anderson, Kholoud Porter, Mark Gompels, Caroline A. Sabin, and for the UK CHIC Steering Committee

Subjects
Diseases of the blood and blood-forming organs, RC633-647.5
Abstract

Since the introduction of highly active antiretroviral therapy, there has been a decline in the incidence of non-Hodgkin’s lymphoma among HIV-infected individuals. We described trends in the incidence of systemic non-Hodgkin’s lymphoma in the UK CHIC Study from 1996–2006 and evaluated the association between immunosuppression and development of systemic non-Hodgkin’s lymphoma: 286/23,155 (1.2%) individuals developed an AIDS-defining lymphoma (258 systemic). Younger age, receipt of highly active antiretroviral therapy and later calendar year were all independently associated with a reduced risk of systemic non-Hodgkin’s lymphoma. A lower latest CD4 count was strongly associated with systemic non-Hodgkin’s lymphoma, in patients who had (RR per log2(cells/mm3) higher: 0.62) and had not (0.70) received highly active antiretroviral therapy. Associations with other measures of immunosuppression, including nadir CD4 count, experience and duration of severe immunosuppression, were generally weaker. Earlier highly active anti-retroviral therapy initiation and wider access to HIV testing is advocated to reduce the risk of systemic non-Hodgkin’s lymphoma.

Published
2009
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7. Assessment of volume depletion in children with malaria.

Author

Timothy Planche, Myriam Onanga, Achim Schwenk, Arnaud Dzeing, Steffen Borrmann, Jean-François Faucher, Antony Wright, Les Bluck, Leigh Ward, Maryvonne Kombila, Peter G Kremsner, and Sanjeev Krishna

Subjects
Medicine
Abstract

BACKGROUND: The degree of volume depletion in severe malaria is currently unknown, although knowledge of fluid compartment volumes can guide therapy. To assist management of severely ill children, and to test the hypothesis that volume changes in fluid compartments reflect disease severity, we measured body compartment volumes in Gabonese children with malaria. METHODS AND FINDINGS: Total body water volume (TBW) and extracellular water volume (ECW) were estimated in children with severe or moderate malaria and in convalescence by tracer dilution with heavy water and bromide, respectively. Intracellular water volume (ICW) was derived from these parameters. Bioelectrical impedance analysis estimates of TBW and ECW were calibrated against dilution methods, and bioelectrical impedance analysis measurements were taken daily until discharge. Sixteen children had severe and 19 moderate malaria. Severe childhood malaria was associated with depletion of TBW (mean [SD] of 37 [33] ml/kg, or 6.7% [6.0%]) relative to measurement at discharge. This is defined as mild dehydration in other conditions. ECW measurements were normal on admission in children with severe malaria and did not rise in the first few days of admission. Volumes in different compartments (TBW, ECW, and ICW) were not related to hyperlactataemia or other clinical and laboratory markers of disease severity. Moderate malaria was not associated with a depletion of TBW. CONCLUSIONS: Significant hypovolaemia does not exacerbate complications of severe or moderate malaria. As rapid rehydration of children with malaria may have risks, we suggest that fluid replacement regimens should aim to correct fluid losses over 12-24 h.

Published
2004
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8. Dense matter with eXTP

Author

Anna L. Watts, WenFei Yu, Juri Poutanen, Shu Zhang, Sudip Bhattacharyya, Slavko Bogdanov, Long Ji, Alessandro Patruno, Thomas E. Riley, Pavel Bakala, Altan Baykal, Federico Bernardini, Ignazio Bombaci, Edward Brown, Yuri Cavecchi, Deepto Chakrabarty, Jérôme Chenevez, Nathalie Degenaar, Melania Del Santo, Tiziana Di Salvo, Victor Doroshenko, Maurizio Falanga, Robert D. Ferdman, Marco Feroci, Angelo F. Gambino, MingYu Ge, Svenja K. Greif, Sebastien Guillot, Can Gungor, Dieter H. Hartmann, Kai Hebeler, Alexander Heger, Jeroen Homan, Rosario Iaria, Jean in’t Zand, Oleg Kargaltsev, Aleksi Kurkela, XiaoYu Lai, Ang Li, XiangDong Li, ZhaoSheng Li, Manuel Linares, FangJun Lu, Simin Mahmoodifar, Mariano Méndez, M. Coleman Miller, Sharon Morsink, Joonas Nättilä, Andrea Possenti, Chanda Prescod-Weinstein, JinLu Qu, Alessandro Riggio, Tuomo Salmi, Andrea Sanna, Andrea Santangelo, Hendrik Schatz, Achim Schwenk, LiMing Song, Eva Šrámková, Benjamin Stappers, Holger Stiele, Tod Strohmayer, Ingo Tews, Laura Tolos, Gabriel Török, David Tsang, Martin Urbanec, Andrea Vacchi, RenXin Xu, YuPeng Xu, Silvia Zane, GuoBao Zhang, ShuangNan Zhang, WenDa Zhang, ShiJie Zheng, and Xia Zhou

Subjects
Physics (General), Astronomy
Abstract

In this White Paper we present the potential of the Enhanced X-ray Timing and Polarimetry (eXTP) mission for determining the nature of dense matter; neutron star cores host an extreme density regime which cannot be replicated in a terrestrial laboratory. The tightest statistical constraints on the dense matter equation of state will come from pulse profile modelling of accretion-powered pulsars, burst oscillation sources, and rotation-powered pulsars. Additional constraints will derive from spin measurements, burst spectra, and properties of the accretion flows in the vicinity of the neutron star. Under development by an international Consortium led by the Institute of High Energy Physics of the Chinese Academy of Science, the eXTP mission is expected to be launched in the mid 2020s.

Published
2018
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9. Three-body resonances in pionless effective field theory

Author

Hans-Werner Hammer, Sebastian König, Achim Schwenk, and Sebastian Dietz

Subjects
Nuclear Theory (nucl-th), Nuclear Theory, Starke Wechselwirkung und exotische Kerne – Abteilung Blaum, FOS: Physical sciences, Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract

We investigate the appearance of resonances in three-body systems using pionless effective field theory at leading order. The Faddeev equation is analytically continued to the unphysical sheet adjacent to the positive real energy axis using a contour rotation. We consider both, the three-boson system and the three-neutron system. For the former, we calculate the trajectory of Borromean three-body Efimov states turning into resonances as they cross the three-body threshold. For the latter, we find no sign of three-body resonances or virtual states at leading order. This result is validated by exploring the level structure of three-body states in a finite volume approach., 18 pages, 10 figures, version published in Phys. Rev. C

Published
2021

10. Equation of state sensitivities when inferring neutron star and dense matter properties

Author

Geert Raaijmakers, Anna L. Watts, S. K. Greif, Achim Schwenk, Kai Hebeler, IoP (FNWI), and High Energy Astrophys. & Astropart. Phys (API, FNWI)

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Neutron Star Interior Composition Explorer, Nuclear Theory, 010308 nuclear & particles physics, Gravitational wave, Open problem, Starke Wechselwirkung und exotische Kerne – Abteilung Blaum, FOS: Physical sciences, Astronomy and Astrophysics, Polytropic process, Bayesian inference, 01 natural sciences, Nuclear Theory (nucl-th), Stars, Neutron star, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, 0103 physical sciences, Piecewise, Statistical physics, Astrophysics - High Energy Astrophysical Phenomena, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR)
Abstract

Understanding the dense matter equation of state at extreme conditions is an important open problem. Astrophysical observations of neutron stars promise to solve this, with NICER poised to make precision measurements of mass and radius for several stars using the waveform modelling technique. What has been less clear, however, is how these mass-radius measurements might translate into equation of state constraints and what are the associated equation of state sensitivities. We use Bayesian inference to explore and contrast the constraints that would result from different choices for the equation of state parametrization; comparing the well-established piecewise polytropic parametrization to one based on physically motivated assumptions for the speed of sound in dense matter. We also compare the constraints resulting from Bayesian inference to those from simple compatibility cuts. We find that the choice of equation of state parametrization and particularly its prior assumptions can have a significant effect on the inferred global mass-radius relation and the equation of state constraints. Our results point to important sensitivities when inferring neutron star and dense matter properties. This applies also to inferences from gravitational wave observations., to appear in MNRAS

Published
2019

11. In-medium similarity renormalization group with three-body operators

Author

J. Hoppe, A. Tichai, Kai Hebeler, M. Heinz, and Achim Schwenk

Subjects
Physics, Work (thermodynamics), Similarity (geometry), Nuclear Theory, Starke Wechselwirkung und exotische Kerne – Abteilung Blaum, Ab initio, FOS: Physical sciences, Renormalization group flow, Renormalization group, Nuclear Theory (nucl-th), Exact results, Scaling, Nuclear theory, Mathematical physics
Abstract

Over the past decade the in-medium similarity renormalization group (IMSRG) approach has proven to be a powerful and versatile ab initio many-body method for studying medium-mass nuclei. So far, the IMSRG was limited to the approximation in which only up to two-body operators are incorporated in the renormalization group flow, referred to as the IMSRG(2). In this work, we extend the IMSRG(2) approach to fully include three-body operators yielding the IMSRG(3) approximation. We use a perturbative scaling analysis to estimate the importance of individual terms in this approximation and introduce truncations that aim to approximate the IMSRG(3) at a lower computational cost. The IMSRG(3) is systematically benchmarked for different nuclear Hamiltonians for ${}^{4}\text{He}$ and ${}^{16}\text{O}$ in small model spaces. The IMSRG(3) systematically improves over the IMSRG(2) relative to exact results. Approximate IMSRG(3) truncations constructed based on computational cost are able to reproduce much of the systematic improvement offered by the full IMSRG(3). We also find that the approximate IMSRG(3) truncations behave consistently with expectations from our perturbative analysis, indicating that this strategy may also be used to systematically approximate the IMSRG(3)., 23 pages, 10 figures, published version

Published
2021

12. Mass measurements of $^{99–101}In$ challenge ab initio nuclear theory of the nuclide $^{100}Sn$

Author

J. Karthein, W. J. Huang, J. D. Holt, Lutz Schweikhard, Gustav R. Jansen, Vladimir Manea, Kai Zuber, Thomas Papenbrock, T. Miyagi, Robert Wolf, Z. H. Sun, Gaute Hagen, Klaus Blaum, K. Chrysalidis, P. Ascher, I. Kulikov, Frank Wienholtz, A. Welker, Dinko Atanasov, Achim Schwenk, M. Mougeot, D. Lunney, Shane Wilkins, Yu. A. Litvinov, Timo Steinsberger, S. R. Stroberg, Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), Université Sciences et Technologies - Bordeaux 1-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), and Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)

Subjects
Speichertechnik - Abteilung Blaum, Nuclear Theory, Proton, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], Ab initio, FOS: Physical sciences, General Physics and Astronomy, Weak interaction, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Nuclear Theory (nucl-th), Nuclear physics, TheoryofComputation_ANALYSISOFALGORITHMSANDPROBLEMCOMPLEXITY, 0103 physical sciences, Isotopes of tin, Nuclear force, Neutron, Nuclear Physics - Experiment, ddc:530, Nuclide, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, Physics, Isotope, 010308 nuclear & particles physics, Nuclear Physics - Theory
Abstract

100Sn is of singular interest for nuclear structure. Its closed-shell proton and neutron configuration exhibit exceptional binding and 100Sn is the heaviest nucleus comprising protons and neutrons in equal number, a feature that enhances the contribution of the short-range, proton-neutron pairing interaction and strongly influences its decay via the weak interaction. Decays studies in the region of 100Sn have attempted to prove its doubly magic character but few have studied it from the ab initio theoretical perspective and none have addressed the odd-proton nuclear forces. Here we present, the first direct measurement of the exotic odd-proton nuclide 100In - the beta-decay daughter of 100Sn - and 99In, only one proton below 100Sn. The most advanced mass spectrometry techniques were used to measure 99In, produced at a rate of only a few ions per second, and to resolve the ground and isomeric states in 101In. The experimental results are confronted with new ab initio many-body approaches. The 100-fold improvement in precision of the 100In mass value exarcebates a striking discrepancy in the atomic mass values of 100Sn deduced from recent beta-decay results., 12 pages, 4 figures, 1 Table

Published
2021
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13. Neutron matter at finite temperature based on chiral effective field theory interactions

Author

Kai Hebeler, C. Wellenhofer, Achim Schwenk, and J. Keller

Subjects
Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Internal energy, Nuclear Theory, 010308 nuclear & particles physics, Starke Wechselwirkung und exotische Kerne – Abteilung Blaum, FOS: Physical sciences, Thermal index, 01 natural sciences, Nuclear Theory (nucl-th), Neutron star, Supernova, Third order, 0103 physical sciences, Thermal, Effective field theory, Neutron, Statistical physics, Nuclear Experiment (nucl-ex), 010306 general physics, Astrophysics - High Energy Astrophysical Phenomena, Nuclear Experiment
Abstract

We study the equation of state of neutron matter at finite temperature based on two- and three-nucleon interactions derived within chiral effective field theory to next-to-next-to-next-to-leading order. The free energy, pressure, entropy, and internal energy are calculated using many-body perturbation theory including terms up to third order around the self-consistent Hartree-Fock solution. We include contributions from three-nucleon interactions without employing the normal-ordering approximation and provide theoretical uncertainty estimates based on an order-by-order analysis in the chiral expansion. Our results demonstrate that thermal effects can be captured remarkably well via a thermal index and a density-dependent effective mass. The presented framework provides the basis for studying the dense matter equation of state at general temperatures and proton fractions relevant for core-collapse supernovae and neutron star mergers., 14 pages, 14 figures, minor changes, published version

Published
2020

14. Electromagnetic properties of 21O for benchmarking nuclear Hamiltonians

Author

B. A. Brown, E. Lunderberg, P. C. Bender, J. Simonis, Robert Roth, C. Loelius, Stefanos Paschalis, D. Bazin, Sebastian Heil, Brenden Longfellow, Brandon Elman, Alexandra Gade, M. Mathy, Klaus Vobig, Marina Petri, T. Hüther, A. Hufnagel, Achim Schwenk, K. Whitmore, Jason D. Holt, J. Belarge, R. Elder, I. Syndikus, Javier Fernandez Menendez, D. Weisshaar, T. Haylett, N. Kobayashi, and Haruna Iwasaki

Subjects
Nuclear and High Energy Physics, Lifetime measurement, Nuclear Theory, FOS: Physical sciences, 01 natural sciences, 7. Clean energy, Nuclear Theory (nucl-th), Ab initio quantum chemistry methods, Simulació per ordinador, 0103 physical sciences, Effective field theory, Nuclear force, ddc:530, Química quàntica, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, Physics, 010308 nuclear & particles physics, Branching fraction, Starke Wechselwirkung und exotische Kerne – Abteilung Blaum, Observable, Computer simulation, lcsh:QC1-999, Excited state, Quadrupole, Ab initio calculations, Effective charges, Atomic physics, Quantum chemistry, Exotic nuclei, lcsh:Physics, Excitation
Abstract

The structure of exotic nuclei provides valuable tests for state-of-the-art nuclear theory. In particular electromagnetic transition rates are more sensitive to aspects of nuclear forces and many-body physics than excitation energies alone. We report the first lifetime measurement of excited states in $^{21}$O, finding $\tau_{1/2^+}=420^{+35}_{-32}\text{(stat)}^{+34}_{-12}\text{(sys)}$\,ps. This result together with the deduced level scheme and branching ratio of several $\gamma$-ray decays are compared to both phenomenological shell-model and ab initio calculations based on two- and three-nucleon forces derived from chiral effective field theory. We find that the electric quadrupole reduced transition probability of $\rm B(E2;1/2^+ \rightarrow 5/2^+_{g.s.}) = 0.71^{+0.07\ +0.02}_{-0.06\ -0.06}$~e$^2$fm$^4$, derived from the lifetime of the $1/2^+$ state, is smaller than the phenomenological result where standard effective charges are employed, suggesting the need for modifications of the latter in neutron-rich oxygen isotopes. We compare this result to both large-space and valence-space ab initio calculations, and by using multiple input interactions we explore the sensitivity of this observable to underlying details of nuclear forces., Comment: 23 pages, 3 figures

Published
2020
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15. Equation of State Constraints from Nuclear Physics, Neutron Star Masses, and Future Moment of Inertia Measurements

Author

Christopher J. Pethick, Achim Schwenk, S. K. Greif, James M. Lattimer, and Kai Hebeler

Subjects
Work (thermodynamics), Equation of state, Nuclear Theory, 010504 meteorology & atmospheric sciences, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, 01 natural sciences, Neutron stars, Nuclear Theory (nucl-th), Nuclear physics, Speed of sound, 0103 physical sciences, Nuclear astrophysics, Effective field theory, Astrophysics::Solar and Stellar Astrophysics, Nuclear Experiment, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Starke Wechselwirkung und exotische Kerne – Abteilung Blaum, Astronomy and Astrophysics, Moment of inertia, Polytrope, Neutron star, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, FORCES, Astrophysics - High Energy Astrophysical Phenomena, ROTATING RELATIVISTIC STARS, MATTER
Abstract

We explore constraints on the equation of state (EOS) of neutron-rich matter based on microscopic calculations up to nuclear densities and observations of neutron stars. In a previous work we showed that predictions based on modern nuclear interactions derived within chiral effective field theory and the observation of two-solar-mass neutron stars result in a robust uncertainty range for neutron star radii and the EOS over a wide range of densities. In this work we extend this study, employing both the piecewise polytrope extension from Hebeler et al. as well as the speed of sound model of Greif et al., and show that moment of inertia measurements of neutron stars can significantly improve the constraints on the EOS and neutron star radii., 11 pages, 10 figures, published version

Published
2020
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16. Constraining the Dense Matter Equation of State with Joint Analysis of NICER and LIGO/Virgo Measurements

Author

Samaya Nissanke, James M. Lattimer, Renee M. Ludlam, Anna L. Watts, Tanja Hinderer, G. Raaijmakers, Achim Schwenk, Sebastien Guillot, S. K. Greif, Kai Hebeler, Thomas E. Riley, IoP (FNWI), High Energy Astrophys. & Astropart. Phys (API, FNWI), Astroparticle Physics (IHEF, IoP, FNWI), Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Centre National d'Études Spatiales [Toulouse] (CNES), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Sub String Theory Cosmology and ElemPart, and Theoretical Physics

Subjects
Equation of state, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], Nuclear Theory, 010504 meteorology & atmospheric sciences, Gaussian, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics, 01 natural sciences, Nuclear Theory (nucl-th), symbols.namesake, Pulsar, 0103 physical sciences, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Neutron Star Interior Composition Explorer, Gravitational wave, Starke Wechselwirkung und exotische Kerne – Abteilung Blaum, Astronomy and Astrophysics, Radius, LIGO, Stars, Space and Planetary Science, symbols, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - High Energy Astrophysical Phenomena
Abstract

The NICER collaboration recently published a joint estimate of the mass and the radius of PSR J0030+0451, derived via X-ray pulse-profile modeling. Raaijmakers et al. (2019) explored the implications of this measurement for the dense matter equation of state (EOS) using two parameterizations of the high-density EOS: a piecewise-polytropic model, and a model based on the speed of sound in neutron stars. In this work we obtain further constraints on the EOS following this approach, but we also include information about the tidal deformability of neutron stars from the gravitational wave signal of the compact binary merger GW170817. We compare the constraints on the EOS to those set by the recent measurement of a 2.14 solar mass pulsar, included as a likelihood function approximated by a Gaussian, and find a small increase in information gain. To show the flexibility of our method, we also explore the possibility that GW170817 was a neutron star-black hole merger, which yields weaker constraints on the EOS., 18 pages, 8 figures. Accepted for publication in ApJ Letters

Published
2020
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17. Shell evolution of $N=40$ isotones towards $^{60}$Ca: First spectroscopy of $^{62}$Ti

Author

Masaki Sasano, S. M. Lenzi, Kazuki Yoshida, E. Sahin, V. Wagner, Hiroyoshi Sakurai, F. Nowacki, T. Isobe, W. Rodriguez, P. Doornenbal, Donghang Yan, D. Kim, T. Motobayashi, M.L. Cortés, Jason D. Holt, V. Lapoux, D. M. Rossi, Toshio Kobayashi, F. Flavigny, A. Giganon, B. D. Linh, F. Château, V. Panin, H. Baba, N. Paul, L. X. Chung, D. Calvet, X. X. Xu, David Steppenbeck, V. Werner, Igor Gašparić, H. N. Liu, A. Delbart, Yosuke Kondo, Si-Ge Chen, L. Achouri, Julien Gibelin, Tomohiro Uesaka, J. M. Gheller, A. Corsi, S. R. Stroberg, Alfredo Poves, Achim Schwenk, Satoshi Takeuchi, Thomas Aumann, R.-B. Gerst, C. Lehr, Jenny Lee, Yasuhiro Togano, C. Hilaire, Y.L. Sun, P. Koseoglou, Nobuyuki Chiga, K. Yoneda, F. Browne, Victor Vaquero, Yuya Kubota, T. Lokotko, T. Koiwai, Zaihong Yang, Takashi Nakamura, S. Wang, J. Simonis, I. Murray, Javier Fernandez Menendez, A. Obertelli, Kazuyuki Ogata, A. Gillibert, H. Toernqvist, M. MacCormick, Masahiro Yasuda, Hideaki Otsu, K. I. Hahn, L. Stuhl, O. Aktas, Hirofumi Yamada, Dóra Sohler, S. Franchoo, Tomás R. Rodríguez, L. Zanetti, K. Moschner, Kathrin Wimmer, S. Y. Park, P. A. Söderström, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Institut Pluridisciplinaire Hubert Curien (IPHC), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), UAM. Departamento de Física Teórica, Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), RIKEN Nishina Center for Accelerator-Based Science, Japan Society for the Promotion of Science, Ministerio de Ciencia, Innovación y Universidades (España), Ministry of Science and Technology of Vietnam, Helmholtz International Center for FAIR, Croatian Science Foundation, National Research, Development and Innovation Office (Hungary), Ministerio de Economía y Competitividad (España), National Research Foundation of Korea, European Commission, Natural Sciences and Engineering Research Council of Canada, Federal Ministry of Education and Research (Germany), and National Research Council of Canada

Subjects
Nuclear and High Energy Physics, Nuclear Theory, Ab initio, FOS: Physical sciences, Shell evolution, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, 01 natural sciences, Radioactive beams, Gamma-ray spectroscopy, Nuclear Theory (nucl-th), 0103 physical sciences, ddc:530, Nuclear Experiment (nucl-ex), 010306 general physics, Spectroscopy, Nuclear Experiment, Physics, 010308 nuclear & particles physics, Island of inversion, Isotone, Starke Wechselwirkung und exotische Kerne – Abteilung Blaum, Física, lcsh:QC1-999, Excited state, Quadrupole, Atomic physics, Nucleon, Ground state, lcsh:Physics
Abstract

7 pags., 4 figs., 1 tab., Excited states in the N=40 isotone Ti were populated via the V(p,2p)Ti reaction at ∼200 MeV/nucleon at the Radioactive Isotope Beam Factory and studied using γ-ray spectroscopy. The energies of the 2 →0 and 4 →2 transitions, observed here for the first time, indicate a deformed Ti ground state. These energies are increased compared to the neighboring Cr and Fe isotones, suggesting a small decrease of quadrupole collectivity. The present measurement is well reproduced by large-scale shell-model calculations based on effective interactions, while ab initio and beyond mean-field calculations do not yet reproduce our findings. The shell-model calculations for Ti show a dominant configuration with four neutrons excited across the N=40 gap. Likewise, they indicate that the N=40 island of inversion extends down to Z=20, disfavoring a possible doubly magic character of the elusive Ca., We thank the RIKEN Nishina Center accelerator staff and the Bi-gRIPS team for the stable operation of the high-intensity Zn beam and for the preparation of the secondary beam setting. K.O. ac-knowledges the support by Grant-in-Aid for Scientific Research of the Japan Society for the Promotion of Science (JSPS) JP16K05352. A.P. is supported in part by the Ministerio de Ciencia, Innovación y Universidades (Spain), Severo Ochoa Programme SEV-2016-0597 and grant PGC-2018-94583. F.B. is supported by the RIKEN Spe-cial Postdoctoral Researcher Program. L.X.C. and B.D.L. would like to thank the Vietnam Ministry of Science and Technology (MOST) for its support through the Physics Development Program Grant No. ÐTÐLCN.25/18. I.G. has been supported by HIC for FAIR and Croatian Science Foundation under projects no. 1257 and 7194. D. So. was supported by the the European Regional Develop-ment Fund contract No. GINOP-2.3.3-15-2016-00034 and the National Research, Development and Innovation Fund of Hungary via Project No. K128947. V.V. acknowledges support from the Span-ish Ministerio de Economía y Competitividad under Contract No. FPA2017-84756-C4-2-P. K.I.H., D.K. and S.Y.P. acknowledge the sup-port from the National Research Foundation of Korea grant No. 2018R1A5A1025563 and 2019M7A1A1033186. The development of MINOS was supported by the European Research Council through the ERC Grant No. MINOS-258567. This work was also supported by the JSPS KAKENHI Grant No. 18K03639, MEXT as “Priority is-sue on post-K computer” (Elucidation of the fundamental laws and evolution of the universe), the Joint Institute for Computational Fundamental Science (JICFuS), the CNS-RIKEN joint project for large-scale nuclear structure calculations, Natural Sciences and Engineering Research Council (NSERC) of Canada, the Deutsche Forschungsgemeinschaft – Projektnummer 279384907 – SFB 1245, the PRISMA Cluster of Excellence, and the BMBF under Contracts No. 05P18RDFN1 and 05P19RDFN1. TRIUMF receives funding via a contribution through the National Research Council Canada. Com-putations were performed at the Jülich Supercomputing Center (JURECA)

Published
2020
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18. Eigenvector continuation as an efficient and accurate emulator for uncertainty quantification

Author

Dean Lee, Kai Hebeler, Achim Schwenk, Andreas Ekström, and Sebastian König

Subjects
Nuclear and High Energy Physics, Other Physics Topics, Nuclear Theory, Ab initio, FOS: Physical sciences, 01 natural sciences, Nuclear Theory (nucl-th), symbols.namesake, 0103 physical sciences, Effective field theory, Nuclear force, ddc:530, Statistical physics, Uncertainty quantification, Theoretical Chemistry, 010306 general physics, Gaussian process, Eigenvalues and eigenvectors, Physics, Basis (linear algebra), 010308 nuclear & particles physics, Starke Wechselwirkung und exotische Kerne – Abteilung Blaum, Observable, lcsh:QC1-999, Computational Mathematics, symbols, lcsh:Physics
Abstract

First principles calculations of atomic nuclei based on microscopic nuclear forces derived from chiral effective field theory (EFT) have blossomed in the past years. A key element of such ab initio studies is the understanding and quantification of systematic and statistical errors arising from the omission of higher-order terms in the chiral expansion as well as the model calibration. While there has been significant progress in analyzing theoretical uncertainties for nucleon-nucleon scattering observables, the generalization to multi-nucleon systems has not been feasible yet due to the high computational cost of evaluating observables for a large set of low-energy couplings. In this Letter we show that a new method called eigenvector continuation (EC) can be used for constructing an efficient and accurate emulator for nuclear many-body observables, thereby enabling uncertainty quantification in multi-nucleon systems. We demonstrate the power of EC emulation with a proof-of-principle calculation that lays out all correlations between bulk ground-state observables in the few-nucleon sector. On the basis of ab initio calculations for the ground-state energy and radius in 4He, we demonstrate that EC is more accurate and efficient compared to established methods like Gaussian processes., Comment: 8 pages, 6 figures, Python code and input files provided as ancillary material, published version

Published
2020
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19. Improved many-body expansions from eigenvector continuation

Author

Mikael Frosini, Andreas Ekström, Pepijn Demol, Thomas Duguet, Achim Schwenk, Dean Lee, V. Somà, Alexander Tichai, Kai Hebeler, Sebastian König, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay

Subjects
Other Physics Topics, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], Nuclear Theory, FOS: Physical sciences, Nuclear Structure, 01 natural sciences, Nuclear Theory (nucl-th), Condensed Matter - Strongly Correlated Electrons, Simple (abstract algebra), 0103 physical sciences, Convergence (routing), ddc:530, Statistical physics, Perturbation theory, Resummation, 010306 general physics, Theoretical Chemistry, Quantum, Eigenvalues and eigenvectors, Physics, NUCLEI, Strongly Correlated Electrons (cond-mat.str-el), 010308 nuclear & particles physics, Nuclear structure, Starke Wechselwirkung und exotische Kerne – Abteilung Blaum, [PHYS.PHYS.PHYS-GEN-PH]Physics [physics]/Physics [physics]/General Physics [physics.gen-ph], Computational Mathematics, A priori and a posteriori, PERTURBATION-THEORY
Abstract

Quantum many-body theory has witnessed tremendous progress in various fields, ranging from atomic and solid-state physics to quantum chemistry and nuclear structure. Due to the inherent computational burden linked to the ab initio treatment of microscopic fermionic systems, it is desirable to obtain accurate results through low-order perturbation theory. In atomic nuclei however, effects such as strong short-range repulsion between nucleons can spoil the convergence of the expansion and make the reliability of perturbation theory unclear. Mathematicians have devised an extensive machinery to overcome the problem of divergent expansions by making use of so-called resummation methods. In large-scale many-body applications such schemes are often of limited use since no a priori analytical knowledge of the expansion is available. We present here eigenvector continuation as an alternative resummation tool that is both efficient and reliable because it is based on robust and simple mathematical principles., 6 pages, 2 figures

Published
2019
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20. Spin-polarized neutron matter, the maximum mass of neutron stars, and GW170817

Author

Ingo Tews and Achim Schwenk

Subjects
Phase transition, Equation of state, 010504 meteorology & atmospheric sciences, Nuclear Theory, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Nuclear physics, Nuclear Theory (nucl-th), High Energy Physics - Phenomenology (hep-ph), 0103 physical sciences, Nuclear force, Neutron, Nuclear Experiment, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Spin-½, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Center (category theory), Starke Wechselwirkung und exotische Kerne – Abteilung Blaum, Astronomy and Astrophysics, Neutron star, Stars, High Energy Physics - Phenomenology, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Astrophysics - High Energy Astrophysical Phenomena
Abstract

We investigate how a phase transition from neutron-star matter to spin-polarized neutron matter affects the equation of state and mass-radius relation of neutron stars. While general extension schemes for the equation of state allow for high pressures inside neutron stars, we find that a phase transition to spin-polarized neutron matter excludes extreme regimes. Hence, such a transition limits the maximum mass of neutron stars to lie below 2.6$-$$2.9 \, M_{\odot}$, depending on the microscopic nuclear forces used, while significantly larger masses could be reached without these constraints. These limits are in good agreement with recent constraints extracted from the neutron-star merger GW170817 and its electromagnetic counterpart. Assuming the description in terms of spin-polarized neutron matter to be valid in the center of neutron stars, we find that stars with a large spin-polarized domain in their core are ruled out by GW170817., 10 pages, 3 figures, published version

Published
2019

21. Dark-matter-nucleus scattering in chiral effective field theory

Author

Philipp Klos, Martin Hoferichter, Javier Fernandez Menendez, and Achim Schwenk

Subjects
Physics, Particle physics, Nuclear Theory, Scattering, Physics beyond the Standard Model, High Energy Physics - Lattice (hep-lat), Dark matter, Starke Wechselwirkung und exotische Kerne – Abteilung Blaum, Nuclear structure, FOS: Physical sciences, 7. Clean energy, Standard Model, High Energy Physics - Experiment, Nuclear Theory (nucl-th), Many-body problem, High Energy Physics - Experiment (hep-ex), High Energy Physics - Phenomenology, High Energy Physics - Phenomenology (hep-ph), High Energy Physics - Lattice, Atomic nucleus, Effective field theory
Abstract

Chiral effective field theory allows one to calculate the response of few-nucleon systems to external currents, both for currents that can be probed in the Standard Model and ones that only exist in Standard-Model extensions. In combination with state-of-the-art many-body methods, the constraints from chiral symmetry can then be implemented in nuclear structure factors that describe the response of atomic nuclei in direct-detection searches for dark matter. We review the present status of this approach, including the role of coherently enhanced two-body currents, the discrimination of dark matter candidates based on the nuclear response functions, and limits on Higgs-portal dark matter., 10 pages, 6 figures, proceedings for The 9th International Workshop on Chiral Dynamics, Durham, North Carolina, USA, September 17-21, 2018

Published
2019

22. Discrepancy between experimental and theoretical $\beta$-decay rates resolved from first principles

Author

Gustav R. Jansen, Jason D. Holt, S. R. Stroberg, Thomas Papenbrock, Petr Navrátil, Kyle Wendt, Gaute Hagen, Achim Schwenk, Sofia Quaglioni, P. Gysbers, and T. D. Morris

Subjects
Physics, Coupling constant, Proton, Nuclear Theory, Starke Wechselwirkung und exotische Kerne – Abteilung Blaum, General Physics and Astronomy, Weak interaction, Coupling (probability), 01 natural sciences, 010305 fluids & plasmas, Nuclear physics, 0103 physical sciences, Atomic nucleus, Neutron, Neutrino, 010306 general physics, Nucleon
Abstract

$\beta$-decay, a process that changes a neutron into a proton (and vice versa), is the dominant decay mode of atomic nuclei. This decay offers a unique window to physics beyond the standard model, and is at the heart of microphysical processes in stellar explosions and the synthesis of the elements in the Universe. For 50 years, a central puzzle has been that observed $\beta$-decay rates are systematically smaller than theoretical predictions. This was attributed to an apparent quenching of the fundamental coupling constant $g_A \simeq $ 1.27 in the nucleus by a factor of about 0.75 compared to the $\beta$-decay of a free neutron. The origin of this quenching is controversial and has so far eluded a first-principles theoretical understanding. Here we address this puzzle and show that this quenching arises to a large extent from the coupling of the weak force to two nucleons as well as from strong correlations in the nucleus. We present state-of-the-art computations of $\beta$-decays from light to heavy nuclei. Our results are consistent with experimental data, including the pioneering measurement for $^{100}$Sn. These theoretical advances are enabled by systematic effective field theories of the strong and weak interactions combined with powerful quantum many-body techniques. This work paves the way for systematic theoretical predictions for fundamental physics problems. These include the synthesis of heavy elements in neutron star mergers and the search for neutrino-less double-$\beta$-decay, where an analogous quenching puzzle is a major source of uncertainty in extracting the neutrino mass scale., Comment: 20 pages, 18 figures

Published
2019

23. Dense matter with eXTP

Author

Xiang-Dong Li, Jean in 't Zand, B. W. Stappers, Sudip Bhattacharyya, Slavko Bogdanov, Holger Stiele, Sharon M. Morsink, Tiziana Di Salvo, Zhaosheng Li, Robert D. Ferdman, Alessandro Riggio, Jin-Lu Qu, Wenfei Yu, Oleg Kargaltsev, R. Iaria, Xia Zhou, Joonas Nättilä, Gabriel Török, David Tsang, Aleksi Kurkela, Laura Tolos, Achim Schwenk, Ingo Tews, Ypeng Xu, Andrea Vacchi, Martin Urbanec, Andrea Santangelo, Xiao Yu Lai, Manuel Linares, Pavel Bakala, Altan Baykal, Anna L. Watts, Alexander Heger, Eva Šrámková, Andrea Sanna, Maurizio Falanga, Ang Li, M. Coleman Miller, Federico Bernardini, Edward F. Brown, Yuri Cavecchi, Jérôme Chenevez, Long Ji, Dieter H. Hartmann, Hendrik Schatz, Ignazio Bombaci, Shuang-Nan Zhang, Silvia Zane, Chanda Prescod-Weinstein, Victor Doroshenko, Kai Hebeler, Guobao Zhang, Tuomo Salmi, Fangjun Lu, Ming-Yu Ge, Melania Del Santo, Deepto Chakrabarty, Mariano Mendez, ShiJie Zheng, Wenda Zhang, S. K. Greif, Alessandro Patruno, Angelo Gambino, Nathalie Degenaar, Simin Mahmoodifar, Juri Poutanen, Marco Feroci, Thomas E. Riley, Shu Zhang, Andrea Possenti, Sebastien Guillot, Tod E. Strohmayer, Jeroen Homan, Can Güngör, Li-Ming Song, Renxin Xu, Universitat Politècnica de Catalunya. Departament de Física, Universitat Politècnica de Catalunya. GAA - Grup d'Astronomia i Astrofísica, High Energy Astrophys. & Astropart. Phys (API, FNWI), Astronomy, Watts, Anna L., Yu, WenFei, Poutanen, Juri, Zhang, Shu, Bhattacharyya, Sudip, Bogdanov, Slavko, Ji, Long, Patruno, Alessandro, Riley, Thomas E., Bakala, Pavel, Baykal, Altan, Bernardini, Federico, Bombaci, Ignazio, Brown, Edward, Cavecchi, Yuri, Chakrabarty, Deepto, Chenevez, Jérôme, Degenaar, Nathalie, Del Santo, Melania, Di Salvo, Tiziana, Doroshenko, Victor, Falanga, Maurizio, Ferdman, Robert D., Feroci, Marco, Gambino, Angelo F., Ge, MingYu, Greif, Svenja K., Guillot, Sebastien, Gungor, Can, Hartmann, Dieter H., Hebeler, Kai, Heger, Alexander, Homan, Jeroen, Iaria, Rosario, Zand, Jean in’t, Kargaltsev, Oleg, Kurkela, Aleksi, Lai, XiaoYu, Li, Ang, Li, XiangDong, Li, ZhaoSheng, Linares, Manuel, Lu, FangJun, Mahmoodifar, Simin, Méndez, Mariano, Coleman Miller, M., Morsink, Sharon, Nättilä, Joona, Possenti, Andrea, Prescod-Weinstein, Chanda, Qu, JinLu, Riggio, Alessandro, Salmi, Tuomo, Sanna, Andrea, Santangelo, Andrea, Schatz, Hendrik, Schwenk, Achim, Song, LiMing, Šrámková, Eva, Stappers, Benjamin, Stiele, Holger, Strohmayer, Tod, Tews, Ingo, Tolos, Laura, Török, Gabriel, Tsang, David, Urbanec, Martin, Vacchi, Andrea, Xu, RenXin, Xu, YuPeng, Zane, Silvia, Zhang, GuoBao, Zhang, ShuangNan, Zhang, WenDa, Zheng, ShiJie, and Zhou, Xia

Subjects
GAMMA-RAY PULSARS, dense matter, Astrophysics::High Energy Astrophysical Phenomena, Polarimetry, General Physics and Astronomy, FOS: Physical sciences, Astrophysics, Neutron, BRIGHTNESS OSCILLATIONS, 7. Clean energy, 01 natural sciences, INNER ACCRETION DISKS, Spectral line, X-ray, equation of state, neutron, X-rays, Physics and Astronomy (all), Equacions d'estat, Pulsar, 0103 physical sciences, MILLISECOND PULSARS, NEUTRON-STAR, RADIUS CONSTRAINTS, 010306 general physics, 010303 astronomy & astrophysics, RELATIVISTIC IRON LINE, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), LIGHT CURVES, Neutrons, Equation of state, QUASI-PERIODIC OSCILLATIONS, X-Rays, Starke Wechselwirkung und exotische Kerne – Abteilung Blaum, Astrophysics::Instrumentation and Methods for Astrophysics, EQUATION-OF-STATE, Accretion (astrophysics), Neutron star, Física::Astronomia i astrofísica [Àrees temàtiques de la UPC], Raigs X, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, Dense matter
Abstract

In this White Paper we present the potential of the Enhanced X-ray Timing and Polarimetry (eXTP) mission for determining the nature of dense matter; neutron star cores host an extreme density regime which cannot be replicated in a terrestrial laboratory. The tightest statistical constraints on the dense matter equation of state will come from pulse profile modelling of accretion-powered pulsars, burst oscillation sources, and rotation-powered pulsars. Additional constraints will derive from spin measurements, burst spectra, and properties of the accretion flows in the vicinity of the neutron star. Under development by an international Consortium led by the Institute of High Energy Physics of the Chinese Academy of Science, the eXTP mission is expected to be launched in the mid 2020s., Comment: Accepted for publication on Sci. China Phys. Mech. Astron. (2019)

Published
2019

24. $^{78}$Ni revealed as a doubly magic stronghold against nuclear deformation

Author

Frédéric Nowacki, L. Olivier, K. Yoneda, Tsuyoshi Miyazaki, H. Wang, I. Stefan, J. Simonis, Zhengyu Xu, C. Santamaria, Javier Fernandez Menendez, Ertan Şahin, D. Calvet, Kazuyuki Ogata, R. Lozeva, C. Louchart, Takaharu Otsuka, Satoshi Takeuchi, Alexandre Obertelli, Yusuke Tsunoda, J.-Y. Roussé, Tadaaki Isobe, F. Giacoppo, F. Château, A. Gottardo, E. C. Pollacco, Jenny Lee, T. Sumikama, K. Matsui, Zs. Vajta, David Steppenbeck, Sophie Péru, S. Nishimura, Zena Patel, Frank Browne, C. M. Shand, Tohru Motobayashi, Shinsuke Ota, S. Momiyama, Hiroyoshi Sakurai, K. Hadynska-Klek, H. Otsu, Alfredo Poves, A. Gillibert, Daisuke Suzuki, Hidetada Baba, A. Delbart, S. Franchoo, Yuki Kubota, V. Lapoux, V. Werner, Pär-Anders Söderström, M. Matsushita, Shunpei Koyama, M. Lettmann, Jason D. Holt, Z. Korkulu, A. Corsi, Alan Peyaud, Achim Schwenk, Yoshiaki Shiga, R. Taniuchi, Jin Wu, L. X. Chung, S. R. Stroberg, M. Niikura, Tomohiro Uesaka, Zs. Dombrádi, Pieter Doornenbal, C. Péron, G. Authelet, J. M. Gheller, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Institut Pluridisciplinaire Hubert Curien (IPHC), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Direction des Applications Militaires (DAM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), and Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Proton, Nuclear Theory, media_common.quotation_subject, Astrophysics::High Energy Astrophysical Phenomena, Strong interaction, FOS: Physical sciences, 01 natural sciences, Asymmetry, Nuclear Theory (nucl-th), Magic number (programming), 0103 physical sciences, Effective field theory, Physics::Atomic and Molecular Clusters, Neutron, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, media_common, Physics, [PHYS]Physics [physics], Multidisciplinary, 010308 nuclear & particles physics, Magic (programming), Atomic nucleus, Atomic physics
Abstract

Nuclear magic numbers, which emerge from the strong nuclear force based on quantum chromodynamics, correspond to fully occupied energy shells of protons, or neutrons inside atomic nuclei. Doubly magic nuclei, with magic numbers for both protons and neutrons, are spherical and extremely rare across the nuclear landscape. While the sequence of magic numbers is well established for stable nuclei, evidence reveals modifications for nuclei with a large proton-to-neutron asymmetry. Here, we provide the first spectroscopic study of the doubly magic nucleus $^{78}$Ni, fourteen neutrons beyond the last stable nickel isotope. We provide direct evidence for its doubly magic nature, which is also predicted by ab initio calculations based on chiral effective field theory interactions and the quasi-particle random-phase approximation. However, our results also provide the first indication of the breakdown of the neutron magic number 50 and proton magic number 28 beyond this stronghold, caused by a competing deformed structure. State-of-the-art phenomenological shell-model calculations reproduce this shape coexistence, predicting further a rapid transition from spherical to deformed ground states with $^{78}$Ni as turning point.

Published
2019
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25. Nuclear structure factors for general spin-independent WIMP-nucleus scattering

Author

Martin Hoferichter, Achim Schwenk, Javier Fernandez Menendez, and Philipp Klos

Subjects
Nuclear Theory, SHELL model, Dark matter, chemistry.chemical_element, FOS: Physical sciences, 01 natural sciences, High Energy Physics - Experiment, Nuclear physics, Nuclear Theory (nucl-th), High Energy Physics - Experiment (hep-ex), Xenon, High Energy Physics - Phenomenology (hep-ph), High Energy Physics - Lattice, WIMP, 0103 physical sciences, medicine, 010306 general physics, Nuclear Experiment, Nuclear theory, Physics, 010308 nuclear & particles physics, Scattering, High Energy Physics - Lattice (hep-lat), Starke Wechselwirkung und exotische Kerne – Abteilung Blaum, Nuclear structure, 3. Good health, High Energy Physics - Phenomenology, medicine.anatomical_structure, chemistry, Nucleus
Abstract

We present nuclear structure factors that describe the generalized spin-independent coupling of weakly interacting massive particles (WIMPs) to nuclei. Our results are based on state-of-the-art nuclear structure calculations using the large-scale nuclear shell model. Starting from quark- and gluon-level operators, we consider all possible coherently enhanced couplings of spin-1/2 and spin-0 WIMPs to one and two nucleons up to third order in chiral effective field theory. This includes a comprehensive discussion of the structure factors corresponding to the leading two-nucleon currents covering, for the first time, the contribution of spin-2 operators. We provide results for the most relevant nuclear targets considered in present and planned dark matter direct detection experiments: fluorine, silicon, argon, and germanium, complementing our previous work on xenon. All results are also publicly available in a Python notebook., 24 pages, 19 figures, Python notebook available at https://theorie.ikp.physik.tu-darmstadt.de/strongint/ChiralEFT4DM.html; further details on nuclear structure added, journal version

Published
2018

26. Double-folding potentials from chiral effective field theory

Author

Pierre Capel, L. Huth, Achim Schwenk, A. B. Balantekin, and V. Durant

Subjects
Nuclear reaction, Nuclear and High Energy Physics, Nuclear Theory, FOS: Physical sciences, 01 natural sciences, 7. Clean energy, Nuclear Theory (nucl-th), Theoretical physics, 0103 physical sciences, Effective field theory, Nuclear fusion, ddc:530, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, Nuclear theory, Elastic scattering, Physics, 010308 nuclear & particles physics, Starke Wechselwirkung und exotische Kerne – Abteilung Blaum, Order (ring theory), lcsh:QC1-999, Physique atomique et nucléaire, Folding (chemistry), Classical mechanics, lcsh:Physics
Abstract

The determination of nucleus–nucleus potentials is important not only to describe the properties of the colliding system, but also to extract nuclear-structure information and for modelling nuclear reactions for astrophysics. We present the first determination of double-folding potentials based on chiral effective field theory at leading, next-to-leading, and next-to-next-to-leading order. To this end, we construct new soft local chiral effective field theory interactions. We benchmark this approach in the 16O–16O system, and present results for cross sections computed for elastic scattering up to 700 MeV in energy, as well as for the astrophysical S-factor of the fusion reaction., SCOPUS: ar.j, info:eu-repo/semantics/published

Published
2018
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27. Large-cutoff behavior of local chiral effective field theory interactions

Author

Achim Schwenk, Ingo Tews, and L. Huth

Subjects
Physics, Work (thermodynamics), Nuclear Theory, 010308 nuclear & particles physics, Starke Wechselwirkung und exotische Kerne – Abteilung Blaum, Ab initio, Phase (waves), Order (ring theory), FOS: Physical sciences, Nuclear matter, 01 natural sciences, 3. Good health, Nuclear Theory (nucl-th), Quantum mechanics, 0103 physical sciences, Bound state, Effective field theory, Cutoff, 010306 general physics, Nuclear Experiment
Abstract

Interactions from chiral effective field theory have been successfully employed in a broad range of \textit{ab initio} calculations of nuclei and nuclear matter, but it has been observed that most results of few- and many-body calculations experience a substantial residual regulator and cutoff dependence. In this work, we investigate the behavior of local chiral potentials at leading order under variation of the cutoff scale for different local regulators. When varying the cutoff, we require that the resulting interaction produces no spurious bound states in the deuteron channel. We find that, for a particular choice of leading-order operators, nucleon-nucleon phase shifts and the deuteron ground-state energy converge to cutoff-independent plateaus, for all regulator functions we investigate. This observation may enable improved calculations with chiral Hamiltonians that also include three-nucleon interactions., 10 pages, 6 figures, published version

Published
2018

28. Chiral power counting of one- and two-body currents in direct detection of dark matter

Author

Achim Schwenk, Philipp Klos, and Martin Hoferichter

Subjects
Nuclear and High Energy Physics, Cosmology and Nongalactic Astrophysics (astro-ph.CO), Nuclear Theory, Matching (graph theory), High Energy Physics::Lattice, Dark matter, Scalar (mathematics), FOS: Physical sciences, Nuclear Theory (nucl-th), High Energy Physics - Phenomenology (hep-ph), Effective field theory, Physics, High Energy Physics::Phenomenology, lcsh:QC1-999, WIMPs, Power (physics), Pseudoscalar, High Energy Physics - Phenomenology, Third order, Amplitude, Quantum electrodynamics, Chiral Lagrangians, lcsh:Physics, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

We present a common chiral power-counting scheme for vector, axial-vector, scalar, and pseudoscalar WIMP-nucleon interactions, and derive all one- and two-body currents up to third order in the chiral expansion. Matching our amplitudes to non-relativistic effective field theory, we find that chiral symmetry predicts a hierarchy amongst the non-relativistic operators. Moreover, we identify interaction channels where two-body currents that so far have not been accounted for become relevant., Comment: 8 pages, 1 table; journal version

Published
2015

29. Chiral interactions up to next-to-next-to-next-to-leading order and nuclear saturation

Author

Kai Hebeler, C. Drischler, and Achim Schwenk

Subjects
Systematic error, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Particle physics, Nuclear Theory, Monte Carlo method, Starke Wechselwirkung und exotische Kerne – Abteilung Blaum, General Physics and Astronomy, FOS: Physical sciences, Nuclear matter, 01 natural sciences, 3. Good health, Nuclear Theory (nucl-th), Fourth order, 0103 physical sciences, Nuclear Experiment (nucl-ex), 010306 general physics, Saturation (chemistry), Astrophysics - High Energy Astrophysical Phenomena, Nuclear theory, Nuclear Experiment
Abstract

We present an efficient Monte Carlo framework for perturbative calculations of infinite nuclear matter based on chiral two-, three-, and four-nucleon interactions. The method enables the incorporation of all many-body contributions in a straightforward and transparent way, and makes it possible to extract systematic uncertainty estimates by performing order-by-order calculations in the chiral expansion as well as the many-body expansion. The versatility of this new framework is demonstrated by applying it to chiral low-momentum interactions, exhibiting a very good many-body convergence up to fourth order. Following these benchmarks, we explore new chiral interactions up to next-to-next-to-next-to-leading order (N$^3$LO). Remarkably, simultaneous fits to the triton and to saturation properties can be achieved, while all three-nucleon low-energy couplings remain natural. The theoretical uncertainties of nuclear matter are significantly reduced when going from next-to-next-to-leading order to N$^3$LO., published version, incl. supplemental material

Published
2017

30. Is a Trineutron Resonance Lower in Energy than a Tetraneutron Resonance?

Author

Stefano Gandolfi, Philipp Klos, J. E. Lynn, Achim Schwenk, and Hans-Werner Hammer

Subjects
Physics, Nuclear Theory, 010308 nuclear & particles physics, Extrapolation, General Physics and Astronomy, chemistry.chemical_element, Resonance, FOS: Physical sciences, 01 natural sciences, Nuclear Theory (nucl-th), chemistry, Quantum mechanics, 0103 physical sciences, Effective field theory, Tetraneutron, Atomic physics, Nuclear Experiment (nucl-ex), 010306 general physics, Quantum, Nuclear Experiment, Helium, Energy (signal processing), Fermi Gamma-ray Space Telescope
Abstract

We present quantum Monte Carlo calculations of few-neutron systems confined in external potentials based on local chiral interactions at next-to-next-to-leading order in chiral effective field theory. The energy and radial densities for these systems are calculated in different external Woods-Saxon potentials. We assume that their extrapolation to zero external-potential depth provides a quantitative estimate of three- and four-neutron resonances. The validity of this assumption is demonstrated by benchmarking with an exact diagonalization in the two-body case. We find that the extrapolated trineutron resonance, as well as the energy for shallow well depths, is lower than the tetraneutron resonance energy. This suggests that a three-neutron resonance exists below a four-neutron resonance in nature and is potentially measurable. To confirm that the relative ordering of three- and four-neutron resonances is not an artifact of the external confinement, we test that the odd-even staggering in the helium isotopic chain is reproduced within this approach. Finally, we discuss similarities between our results and ultracold Fermi gases., 6 pages, 5 figures, version compatible with published letter

Published
2016

31. Neutron matter from chiral two- and three-nucleon calculations up to N3LO

Author

C. Drischler, Achim Schwenk, Kai Hebeler, and A. Carbone

Subjects
Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Particle physics, Nuclear Theory, 010308 nuclear & particles physics, Equation of state (cosmology), Order (ring theory), FOS: Physical sciences, 7. Clean energy, 01 natural sciences, Nuclear Theory (nucl-th), Third order, 0103 physical sciences, Effective field theory, Neutron, Ideal (ring theory), Perturbation theory, Präzisionsexperimente - Abteilung Blaum, Astrophysics - High Energy Astrophysical Phenomena, 010306 general physics, Nucleon
Abstract

Neutron matter is an ideal laboratory for nuclear interactions derived from chiral effective field theory since all contributions are predicted up to next-to-next-to-next-to-leading order (N$^3$LO) in the chiral expansion. By making use of recent advances in the partial-wave decomposition of three- nucleon (3N) forces, we include for the first time N$^3$LO 3N interactions in many-body perturbation theory (MBPT) up to third order and in self-consistent Green's function theory (SCGF). Using these two complementary many-body frameworks we provide improved predictions for the equation of state of neutron matter at zero temperature and also analyze systematically the many-body convergence for different chiral EFT interactions. Furthermore, we present an extension of the normal-ordering framework to finite temperatures. These developments open the way to improved calculations of neutron-rich matter including estimates of theoretical uncertainties for astrophysical applications., Comment: minor changes, published version

Published
2016

32. Pairing in neutron matter: New uncertainty estimates and three-body forces

Author

C. Drischler, Achim Schwenk, Kai Hebeler, and Thomas Krüger

Subjects
Physics, Body force, Imagination, High Energy Astrophysical Phenomena (astro-ph.HE), Nuclear Theory, 010308 nuclear & particles physics, media_common.quotation_subject, Order (ring theory), FOS: Physical sciences, Broyden's method, 01 natural sciences, Nuclear physics, Nuclear Theory (nucl-th), Pairing, 0103 physical sciences, Convergence (routing), Effective field theory, Neutron, Statistical physics, Präzisionsexperimente - Abteilung Blaum, 010306 general physics, Astrophysics - High Energy Astrophysical Phenomena, media_common
Abstract

We present solutions of the BCS gap equation in the channels ${}^1S_0$ and ${}^3P_2-{}^3F_2$ in neutron matter based on nuclear interactions derived within chiral effective field theory (EFT). Our studies are based on a representative set of nonlocal nucleon-nucleon (NN) plus three-nucleon (3N) interactions up to next-to-next-to-next-to-leading order (N$^3$LO) as well as local and semilocal chiral NN interactions up to N$^2$LO and N$^4$LO, respectively. In particular, we investigate for the first time the impact of subleading 3N forces at N$^3$LO on pairing gaps and also derive uncertainty estimates by taking into account results for pairing gaps at different orders in the chiral expansion. Finally, we discuss different methods for obtaining self-consistent solutions of the gap equation. Besides the widely-used quasi-linear method by Khodel et al. we demonstrate that the modified Broyden method is well applicable and exhibits a robust convergence behavior. In contrast to Khodel's method it is based on a direct iteration of the gap equation without imposing an auxiliary potential and is straightforward to implement.

Published
2016

33. Changes in outcome of persons initiating highly active antiretroviral therapy at a CD4 count less than 50 Cells/mm3

Author

Margaret A. Johnson, Richard Gilson, John P. Walsh, Brian Gazzard, Sarah Walker, Chloe Orkin, Valerie Delpech, Caroline A. Sabin, Teresa Hill, Jane Anderson, Philippa Easterbrook, Achim Schwenk, Clifford Leen, Martin Fisher, and Kholoud Porter

Subjects
Adult, Male, medicine.medical_specialty, Anti-HIV Agents, HIV Infections, Sex Factors, Acquired immunodeficiency syndrome (AIDS), Internal medicine, Antiretroviral Therapy, Highly Active, medicine, Humans, Pharmacology (medical), Immunodeficiency, business.industry, Age Factors, Odds ratio, Viral Load, medicine.disease, Antiretroviral therapy, Confidence interval, United Kingdom, CD4 Lymphocyte Count, Regimen, Infectious Diseases, Treatment Outcome, Cohort, Immunology, Female, business, Viral load
Abstract

BACKGROUND: Although HIV treatment guidelines recommend highly active antiretroviral therapy (HAART) initiation before reaching a CD4 count of 200 cells/mm3, many people in resource-rich settings, and a substantial proportion in resource-limited settings, present at levels

Published
2016
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34. Analysis strategies for general spin-independent WIMP-nucleus scattering

Author

Martin Hoferichter, Achim Schwenk, Philipp Klos, and Javier Fernandez Menendez

Subjects
Quantum chromodynamics, Physics, Particle physics, Cosmology and Nongalactic Astrophysics (astro-ph.CO), Isovector, Nuclear Theory, 010308 nuclear & particles physics, Scattering, Physics beyond the Standard Model, FOS: Physical sciences, 01 natural sciences, High Energy Physics - Experiment, Nuclear Theory (nucl-th), High Energy Physics - Experiment (hep-ex), High Energy Physics - Phenomenology, High Energy Physics - Phenomenology (hep-ph), WIMP, 0103 physical sciences, Effective field theory, 010306 general physics, Structure factor, Free parameter, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

We propose a formalism for the analysis of direct-detection dark-matter searches that covers all coherent responses for scalar and vector interactions and incorporates QCD constraints imposed by chiral symmetry, including all one- and two-body WIMP-nucleon interactions up to third order in chiral effective field theory. One of the free parameters in the WIMP-nucleus cross section corresponds to standard spin-independent searches, but in general different combinations of new-physics couplings are probed. We identify the interference with the isovector counterpart of the standard spin-independent response and two-body currents as the dominant corrections to the leading spin-independent structure factor, and discuss the general consequences for the interpretation of direct-detection experiments, including minimal extensions of the standard spin-independent analysis. Fits for all structure factors required for the scattering off xenon targets are provided based on state-of-the-art nuclear shell-model calculations., 20 pages, 7 figures; v2 includes the two-body current related to the trace anomaly of the QCD energy-momentum tensor

Published
2016

35. Neutron and weak-charge distributions of the 48Ca nucleus

Author

Gustav R. Jansen, Mirko Miorelli, Sonia Bacca, J. Simonis, Thomas Papenbrock, K. A. Wendt, B. D. Carlsson, Kai Hebeler, Gaute Hagen, Christian Forssén, Nir Barnea, C. Drischler, Morten Hjorth-Jensen, Giuseppina Orlandini, Witold Nazarewicz, Andreas Ekström, and Achim Schwenk

Subjects
Physics, Proton, 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, Nuclear Theory, General Physics and Astronomy, Neutron scattering, 01 natural sciences, Electric charge, Nuclear physics, Neutron star, Physics and Astronomy (all), Charge radius, 0103 physical sciences, Atomic nucleus, Neutron, Physics::Atomic Physics, Nuclear Experiment, 010306 general physics, s-process
Abstract

What is the size of the atomic nucleus? This deceivably simple question is difficult to answer. Although the electric charge distributions in atomic nuclei were measured accurately already half a century ago, our knowledge of the distribution of neutrons is still deficient. In addition to constraining the size of atomic nuclei, the neutron distribution also impacts the number of nuclei that can exist and the size of neutron stars. We present an ab initio calculation of the neutron distribution of the neutron-rich nucleus Ca-48. We show that the neutron skin (difference between the radii of the neutron and proton distributions) is significantly smaller than previously thought. We also make predictions for the electric dipole polarizability and the weak form factor; both quantities that are at present targeted by precision measurements. Based on ab initio results for Ca-48, we provide a constraint on the size of a neutron star.

Published
2016

36. Colloquium: Measuring the neutron star equation of state using x-ray timing

Author

Laura Tolos, Juri Poutanen, Achim Schwenk, Luigi Stella, Anna L. Watts, Sharon M. Morsink, Dimitrios Psaltis, Andrew W. Steiner, M. Coleman Miller, Alessandro Patruno, Kai Hebeler, Frederick K. Lamb, Nils Andersson, Marco Feroci, Feryal Özel, Michiel van der Klis, G. L. Israel, Deepto Chakrabarty, High Energy Astrophys. & Astropart. Phys (API, FNWI), ITA, USA, GBR, DEU, ESP, CAN, FIN, and NLD

Subjects
Physics, Orbital speed, ta115, Photon, Neutron Star Interior Composition Explorer, 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, General Physics and Astronomy, Astrophysics, Moment of inertia, Compact star, Magnetar, 01 natural sciences, Stars, Neutron star, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, 010303 astronomy & astrophysics
Abstract

One of the primary science goals of the next generation of hard x-ray timing instruments is to determine the equation of state of matter at supranuclear densities inside neutron stars by measuring the radius of neutron stars with different masses to accuracies of a few percent. Three main techniques can be used to achieve this goal. The first involves waveform modeling. The flux observed from a hotspot on the neutron star surface offset from the rotational pole will be modulated by the star’s rotation, and this periodic modulation at the spin frequency is called a pulsation. As the photons propagate through the curved spacetime of the star, information about mass and radius is encoded into the shape of the waveform (pulse profile) via special and general-relativistic effects. Using pulsations from known sources (which have hotspots that develop either during thermonuclear bursts or due to channeled accretion) it is possible to obtain tight constraints on mass and radius. The second technique involves characterizing the spin distribution of accreting neutron stars. A large collecting area enables highly sensitive searches for weak or intermittent pulsations (which yield spin) from the many accreting neutron stars whose spin rates are not yet known. The most rapidly rotating stars provide a clean constraint, since the limiting spin rate where the equatorial surface velocity is comparable to the local orbital velocity, at which mass shedding occurs, is a function of mass and radius. However, the overall spin distribution also provides a guide to the torque mechanisms in operation and the moment of inertia, both of which can depend sensitively on dense matter physics. The third technique is to search for quasiperiodic oscillations in x-ray flux associated with global seismic vibrations of magnetars (the most highly magnetized neutron stars), triggered by magnetic explosions. The vibrational frequencies depend on stellar parameters including the dense matter equation of state, and large-area x-ray timing instruments would provide much improved detection capability. An illustration is given of how these complementary x-ray timing techniques can be used to constrain the dense matter equation of state and the results that might be expected from a 10 m2 instrument are discussed. Also discussed are how the results from such a facility would compare to other astronomical investigations of neutron star properties.

Published
2016

37. Unexpectedly large charge radii of neutron-rich calcium isotopes

Author

Gustav R. Jansen, J. Simonis, Andreas Ekström, Wilfried Nörtershäuser, Witold Nazarewicz, Klaus Wendt, Deyan T. Yordanov, Mark Bissell, K. Kreim, Rainer Neugart, Gerda Neyens, Magda Kowalska, M. Hammen, Thomas Papenbrock, Klaus Blaum, Kai Hebeler, Achim Schwenk, R. F. Garcia Ruiz, J. Papuga, N. Frömmgen, Jason D. Holt, Gaute Hagen, Institut de Physique Nucléaire d'Orsay (IPNO), and Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Nuclear Theory, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], General Physics and Astronomy, FOS: Physical sciences, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, 01 natural sciences, Isotopes of calcium, Nuclear Theory (nucl-th), 0103 physical sciences, Nuclear Physics - Experiment, Neutron, MAGIC (telescope), Nuclear Experiment (nucl-ex), 010306 general physics, Spectroscopy, Nuclear Experiment, Magic number (physics), Physics, Isotope, 010308 nuclear & particles physics, Charge (physics), 13. Climate action, Nuclear Physics - Theory, Atomic nucleus, Atomic physics, Präzisionsexperimente - Abteilung Blaum
Abstract

Despite being a complex many-body system, the atomic nucleus exhibits simple structures for certain "magic" numbers of protons and neutrons. The calcium chain in particular is both unique and puzzling: evidence of doubly-magic features are known in 40,48Ca, and recently suggested in two radioactive isotopes, 52,54Ca. Although many properties of experimentally known Ca isotopes have been successfully described by nuclear theory, it is still a challenge to predict their charge radii evolution. Here we present the first measurements of the charge radii of 49,51,52Ca, obtained from laser spectroscopy experiments at ISOLDE, CERN. The experimental results are complemented by state-of-the-art theoretical calculations. The large and unexpected increase of the size of the neutron-rich calcium isotopes beyond N = 28 challenges the doubly-magic nature of 52Ca and opens new intriguing questions on the evolution of nuclear sizes away from stability, which are of importance for our understanding of neutron-rich atomic nuclei., Comment: Submitted version. See original publication (doi:10.1038/nphys3645) for final version

Published
2016
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38. The In-Medium Similarity Renormalization Group: A Novel Ab Initio Method for Nuclei

Author

T. D. Morris, Koshiroh Tsukiyama, Achim Schwenk, Heiko Hergert, and Scott Bogner

Subjects
Physics, Nuclear Theory, 010308 nuclear & particles physics, General Physics and Astronomy, FOS: Physical sciences, Unitary transformation, Renormalization group, 01 natural sciences, Nuclear Theory (nucl-th), Theoretical physics, symbols.namesake, Coupled cluster, Factorization, 0103 physical sciences, symbols, Perturbation theory (quantum mechanics), Circular symmetry, 010306 general physics, Hamiltonian (quantum mechanics), Wave function
Abstract

We present a comprehensive review of the In-Medium Similarity Renormalization Group (IM-SRG), a novel ab inito method for nuclei. The IM-SRG employs a continuous unitary transformation of the many-body Hamiltonian to decouple the ground state from all excitations, thereby solving the many-body problem. Starting from a pedagogical introduction of the underlying concepts, the IM-SRG flow equations are developed for systems with and without explicit spherical symmetry. We study different IM-SRG generators that achieve the desired decoupling, and how they affect the details of the IM-SRG flow. Based on calculations of closed-shell nuclei, we assess possible truncations for closing the system of flow equations in practical applications, as well as choices of the reference state. We discuss the issue of center-of-mass factorization and demonstrate that the IM-SRG ground-state wave function exhibits an approximate decoupling of intrinsic and center-of-mass degrees of freedom, similar to Coupled Cluster (CC) wave functions. To put the IM-SRG in context with other many-body methods, in particular many-body perturbation theory and non-perturbative approaches like CC, a detailed perturbative analysis of the IM-SRG flow equations is carried out. We conclude with a discussion of ongoing developments, including IM-SRG calculations with three-nucleon forces, the multi-reference IM-SRG for open-shell nuclei, first non-perturbative derivations of shell- model interactions, and the consistent evolution of operators in the IM-SRG. We dedicate this review to the memory of Gerry Brown, one of the pioneers of many-body calculations of nuclei., 92 pages, 33 figures, to appear in Physics Reports

Published
2015

39. Ground and excited states of doubly open-shell nuclei from ab initio valence-space Hamiltonians

Author

Achim Schwenk, S. R. Stroberg, Heiko Hergert, Jason D. Holt, and Scott Bogner

Subjects
Physics, Valence (chemistry), Nuclear Theory, 010308 nuclear & particles physics, Yrast, Ab initio, FOS: Physical sciences, Renormalization group, 7. Clean energy, 01 natural sciences, Nuclear Theory (nucl-th), Isotopes of neon, Excited state, Neutron number, 0103 physical sciences, Physics::Atomic and Molecular Clusters, Nuclear Experiment (nucl-ex), Atomic physics, 010306 general physics, Open shell, Nuclear Experiment
Abstract

We present ab initio predictions for ground and excited states of doubly open-shell fluorine and neon isotopes based on chiral two- and three-nucleon interactions. We use the in-medium similarity renormalization group, in both flow-equation and Magnus formulations, to derive mass-dependent sd valence-space Hamiltonians. The experimental ground-state energies are reproduced through neutron number N=14, beyond which a new targeted normal-ordering procedure improves agreement with data and large-scale multi-reference calculations. For spectroscopy, we focus on neutron-rich 23-26F and 24-26Ne isotopes near N=14,16 magic numbers. In all cases we find an agreement with experiment competitive with established phenomenology. Moreover, yrast states are well described in 20Ne and 24Mg, providing an ab initio description of deformation in the medium-mass region., 6 pages, 4 figures, published version

Published
2015

40. Emission of neutrino-antineutrino pairs by hadronic bremsstrahlung processes

Author

Achim Schwenk, Rishi Sharma, and Sonia Bacca

Subjects
Physics, Focus (computing), Nuclear Theory, 010308 nuclear & particles physics, QC1-999, Astrophysics::High Energy Astrophysical Phenomena, Hadron, Bremsstrahlung, FOS: Physical sciences, 01 natural sciences, Nuclear physics, Nuclear Theory (nucl-th), Supernova, Pair production, 0103 physical sciences, High Energy Physics::Experiment, Neutrino, 010306 general physics, Nuclear Experiment
Abstract

We review our recent calculations of neutrino-antineutrino pair production from bremsstrahlung processes in hadronic collisions at temperature and densities relevant for core-collapse supernovae. We focus on neutron-neutron and neutron-alpha collisions., 8 pages, 4 figures, proceedings of the NN2015 conference, Catania, 21-26 June, 2015

Published
2015

41. Chiral Three-Nucleon Interactions in Light Nuclei, Neutron-$\alpha$ Scattering, and Neutron Matter

Author

Stefano Gandolfi, Ingo Tews, Kevin Schmidt, Joseph Carlson, Achim Schwenk, J. E. Lynn, and Alexandros Gezerlis

Subjects
Physics, Particle physics, Nuclear Theory, 010308 nuclear & particles physics, Scattering, General Physics and Astronomy, Order (ring theory), Neutron scattering, 01 natural sciences, 7. Clean energy, Small-angle neutron scattering, Inelastic neutron scattering, 3. Good health, 0103 physical sciences, Effective field theory, Neutron, 010306 general physics, Nucleon, Nuclear Experiment
Abstract

We present quantum Monte Carlo calculations of light nuclei, neutron-$\alpha$ scattering, and neutron matter using local two- and three-nucleon ($3N$) interactions derived from chiral effective field theory up to next-to-next-to-leading order (N$^2$LO). The two undetermined $3N$ low-energy couplings are fit to the $^4$He binding energy and, for the first time, to the spin-orbit splitting in the neutron-$\alpha$ $P$-wave phase shifts. Furthermore, we investigate different choices of local $3N$-operator structures and find that chiral interactions at N$^2$LO are able to simultaneously reproduce the properties of $A=3,4,5$ systems and of neutron matter, in contrast to commonly used phenomenological $3N$ interactions., Comment: 5 pages, 3 figures, 1 table - updated version: small wording changes, one reference change

Published
2015

42. Exploring sd-shell nuclei from two- and three-nucleon interactions with realistic saturation properties

Author

J. Simonis, Achim Schwenk, Javier Fernandez Menendez, Jason D. Holt, and Kai Hebeler

Subjects
Physics, Nuclear Theory, 010308 nuclear & particles physics, FOS: Physical sciences, Nuclear matter, 01 natural sciences, 7. Clean energy, Nuclear Theory (nucl-th), Nuclear physics, symbols.namesake, Excited state, 0103 physical sciences, symbols, Neutron, Nuclear Experiment (nucl-ex), Atomic physics, 010306 general physics, Nucleon, Saturation (chemistry), Hamiltonian (quantum mechanics), Nuclear Experiment, Nuclear theory
Abstract

We study ground- and excited-state properties of all sd-shell nuclei with neutron and proton numbers 8, 6 pages, 4 figures

Published
2015

43. Quantum Monte Carlo calculations of neutron matter with chiral three-body forces

Author

Alexandros Gezerlis, Achim Schwenk, Ingo Tews, and Stefano Gandolfi

Subjects
Physics, Nuclear Theory, 010308 nuclear & particles physics, Equation of state (cosmology), Quantum Monte Carlo, Monte Carlo method, Order (ring theory), FOS: Physical sciences, 01 natural sciences, Nuclear Theory (nucl-th), Auxiliary field, Quantum mechanics, Quantum electrodynamics, 0103 physical sciences, Effective field theory, Neutron, Diffusion Monte Carlo, 010306 general physics
Abstract

Chiral effective field theory (EFT) enables a systematic description of low-energy hadronic interactions with controlled theoretical uncertainties. For strongly interacting systems, quantum Monte Carlo (QMC) methods provide some of the most accurate solutions, but they require as input local potentials. We have recently constructed local chiral nucleon-nucleon (NN) interactions up to next-to-next-to-leading order (N$^2$LO). Chiral EFT naturally predicts consistent many-body forces. In this paper, we consider the leading chiral three-nucleon (3N) interactions in local form. These are included in auxiliary field diffusion Monte Carlo (AFDMC) simulations. We present results for the equation of state of neutron matter and for the energies and radii of neutron drops. In particular, we study the regulator dependence at the Hartree-Fock level and in AFDMC and find that present local regulators lead to less repulsion from 3N forces compared to the usual nonlocal regulators., 10 pages, 8 figures, 1 table, published version

Published
2015

44. Ground-state electromagnetic moments of calcium isotopes

Author

R. F. Garcia Ruiz, Deyan T. Yordanov, K. Kreim, Javier Fernandez Menendez, Klaus Blaum, Gerda Neyens, J. Papuga, Rainer Neugart, N. Frömmgen, J. Simonis, Magda Kowalska, Jason D. Holt, Wilfried Nörtershäuser, Mark Bissell, Alfredo Poves, M. Hammen, Achim Schwenk, Frédéric Nowacki, and UAM. Departamento de Física Teórica

Subjects
Physics, Nuclear and High Energy Physics, Nuclear Theory, Field (physics), Magnetic moment, FOS: Physical sciences, Física, nucl-ex, 7. Clean energy, 3. Good health, Nuclear Theory (nucl-th), 13. Climate action, Nuclear Physics - Theory, Quadrupole, Effective field theory, Nuclear force, Nuclear Physics - Experiment, Präzisionsexperimente - Abteilung Blaum, Nuclear Experiment (nucl-ex), Atomic physics, Nuclear Experiment, Ground state, Spin (physics), Hyperfine structure
Abstract

Artículo escrito por un elevado número de autores, solo se referencian el que aparece en primer lugar, el nombre del grupo de colaboración, si le hubiere, y los autores pertenecientes a la UAM, Background: The neutron-rich calcium isotopes have gained particular interest as evidence of closed-shell structures has recently been found in two exotic nuclei, at N=32 and N=34. Additionally, the study of such neutron-rich systems has revealed new aspects of nuclear forces, in particular regarding the role of three-nucleon forces. Purpose: We study the electromagnetic properties of Ca isotopes around the neutron number N=32. Methods: High-resolution bunched-beam collinear laser spectroscopy was used to measure the optical hyperfine spectra of the Ca43-51 isotopes. Results: The ground-state magnetic moments of Ca49,51 and quadrupole moments of Ca47,49,51 were measured for the first time, and the Ca51 ground-state spin I=3/2 was determined in a model-independent way. Our experimental results are compared with state-of-the-art shell-model calculations using both phenomenological interactions and microscopic interactions derived from chiral effective field theory. Conclusions: The results for the ground-state moments of neutron-rich isotopes are in excellent agreement with predictions of interactions derived from chiral effective field theory including three-nucleon forces. Lighter isotopes illustrate the presence of particle-hole excitations of the Ca40 core in their ground state. Our results provide a critical test of modern nuclear theories, and give direct answer to the evolution of ground-state electromagnetic properties in the Ca isotopic chain across three doubly closed-shell configurations at N=20, 28, 32 of this unique system, This work was supported by the IAP-project P7/12, the GOA grant 15/010 KU Leuven, NSF Grant No. PHY-1068217, the BMBF Contracts No. 05P12RDCIC and No. 06DA70471, the Max-Planck Society, the EU FP7 via ENSAR No. 262010, the DFG through Grant No. SFB 634, ERC Grant No. 307986 STRONGINT, the Helmholtz Alliance HA216/EMMI, and MINECO (SPAIN) (FPA2011-29854). Computations were performed on JUROPA at the Julich Supercomputing Center. We would like to thank the ISOLDE technical group for their support and assistance. International Research Fellowship of the Japan Society for the Promotion of Science (JSPS) and JSPS KAKENHI Grant No. 26.04323

Published
2015

45. Neutrino-pair bremsstrahlung from nucleon-$\alpha$ versus nucleon-nucleon scattering

Author

Achim Schwenk, Rishi Sharma, and Sonia Bacca

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Range (particle radiation), Nuclear Theory, Scattering, Astrophysics::High Energy Astrophysical Phenomena, Bremsstrahlung, Nucleon spin structure, 7. Clean energy, Nuclear physics, Supernova, Production (computer science), Neutrino, Nucleon, Nuclear Experiment, Astrophysics - High Energy Astrophysical Phenomena
Abstract

We study the impact of the nucleon-$\alpha$ P-wave resonances on neutrino-pair bremsstrahlung. Because of the non-central spin-orbit interaction, these resonances lead to an enhanced contribution to the nucleon spin structure factor for temperatures $T \lesssim 4$ MeV. If the $\alpha$-particle fraction is significant and the temperature is in this range, this contribution is competitive with neutron-neutron bremsstrahlung. This may be relevant for neutrino production in core-collapse supernovae or other dense astrophysical environments. Similar enhancements are expected for resonant non-central nucleon-nucleus interactions., Comment: 6 pages, 4 figures

Published
2014

46. Breakdown of the Isobaric Multiplet Mass Equation for the A = 20 and 21 Multiplets

Author

A. Grossheim, A. Bader, Javier Fernandez Menendez, R. Klawitter, K. G. Leach, B. A. Brown, B.E. Schultz, H. Heggen, A. Lennarz, J. Lassen, A. Teigelhöfer, Maxime Brodeur, Achim Schwenk, Corina Andreoiu, Aaron Gallant, U. Chowdhury, A.A. Kwiatkowski, T.D. Macdonald, A. Magilligan, A. Chaudhuri, Jason D. Holt, Sebastian Raeder, Jens Dilling, and J. Simonis

Subjects
Physics, Isotope, 010308 nuclear & particles physics, Nuclear Theory, FOS: Physical sciences, General Physics and Astronomy, Mass spectrometry, Penning trap, 01 natural sciences, Atomic mass, Mass formula, Isospin, 0103 physical sciences, Isobaric process, Nuclear Experiment (nucl-ex), Atomic physics, Präzisionsexperimente - Abteilung Blaum, 010306 general physics, Nuclear Experiment, Multiplet
Abstract

Using the Penning trap mass spectrometer TITAN, we performed the first direct mass measurements of 20,21Mg, isotopes that are the most proton-rich members of the A = 20 and A = 21 isospin multiplets. These measurements were possible through the use of a unique ion-guide laser ion source, a development that suppressed isobaric contamination by six orders of magnitude. Compared to the latest atomic mass evaluation, we find that the mass of 21Mg is in good agreement but that the mass of 20Mg deviates by 3{\sigma}. These measurements reduce the uncertainties in the masses of 20,21Mg by 15 and 22 times, respectively, resulting in a significant departure from the expected behavior of the isobaric multiplet mass equation in both the A = 20 and A = 21 multiplets. This presents a challenge to shell model calculations using either the isospin non-conserving USDA/B Hamiltonians or isospin non-conserving interactions based on chiral two- and three-nucleon forces., Comment: 5 pages, 2 figures

Published
2014

47. Renormalization Group and Effective Field Theory Approaches to Many-Body Systems

Author

Achim Schwenk, Janos Polonyi, Achim Schwenk, and Janos Polonyi

Subjects
Mathematical physics, Nuclear physics, Quantum statistics, Condensed matter
Abstract

There have been many recent and important developments based on effective field theory and the renormalization group in atomic, condensed matter, nuclear and high-energy physics. These powerful and versatile methods provide novel approaches to study complex and strongly interacting many-body systems in a controlled manner. The six extensive lectures gathered in this volume combine selected introductory and interdisciplinary presentations focused on recent applications of effective field theory and the renormalization group to many-body problems in such diverse fields as BEC, DFT, extreme matter, Fermi-liquid theory and gauge theories. Primarily aimed at graduate students and junior researchers, they offer an opportunity to explore fundamental physics across subfield boundaries at an early stage in their careers.

Published
2012

48. Symmetry energy, neutron skin, and neutron star radius from chiral effective field theory interactions

Author

Achim Schwenk and Kai Hebeler

Subjects
Physics, Nuclear and High Energy Physics, Nuclear Theory, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Radius, Symmetry (physics), Nuclear Theory (nucl-th), Nuclear physics, Neutron star, Effective field theory, Neutron, Astrophysics::Earth and Planetary Astrophysics, Nuclear Experiment, Energy (signal processing)
Abstract

We discuss neutron matter calculations based on chiral effective field theory interactions and their predictions for the symmetry energy, the neutron skin of 208 Pb, and for the radius of neutron stars., 7 pages, 8 figures, short review article, to appear in EPJA special issue on symmetry energy

Published
2014

49. Microscopic calculations and energy expansions for neutron-rich matter

Author

C. Drischler, Achim Schwenk, V. Somà, Institut f¨ur Kernphysik, Technische Universit¨at Darmstadt, 64289 Darmstadt, Département de Physique Nucléaire (ex SPhN) (DPHN), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay

Subjects
Physics, Nuclear and High Energy Physics, Proton, Nuclear Theory, 010308 nuclear & particles physics, Ab initio, FOS: Physical sciences, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear matter, 01 natural sciences, Symmetry (physics), Nuclear Theory (nucl-th), Astrophysics - Solar and Stellar Astrophysics, Quantum electrodynamics, 0103 physical sciences, Effective field theory, Nuclear force, Neutron, Nuclear Experiment (nucl-ex), 010306 general physics, Parametrization, Nuclear Experiment, Solar and Stellar Astrophysics (astro-ph.SR)
Abstract

We investigate asymmetric nuclear matter with two- and three-nucleon interactions based on chiral effective field theory, where three-body forces are fit only to light nuclei. Focusing on neutron-rich matter, we calculate the energy for different proton fractions and include estimates of the theoretical uncertainty. We use our ab-initio results to test the quadratic expansion around symmetric matter with the symmetry energy term, and confirm its validity for highly asymmetric systems. Our calculations are in remarkable agreement with an empirical parametrization for the energy density. These findings are very useful for astrophysical applications and for developing new equations of state., Comment: 15 pages, 9 figures, published version

Published
2014
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50. The Large Observatory For x-ray Timing

Author

Antonios Manousakis, S. Boutloukos, F. Zwart, Jose M. Torrejon, C. Pittori, Alessandro Drago, Dieter H. Hartmann, Feryal Özel, T. J. L. Courvoisier, Tim Johannsen, Jordi José, M. Michalska, Christian Schmid, I. Rashevskaya, Gottfried Kanbach, V. Petracek, L. Bradley, Allan Hornstrup, M. H. Erkut, Sergio Campana, Rudy Wijnands, Andrew Cumming, Nils Andersson, Tomaso Belloni, M. C. Miller, Roman Wawrzaszek, Stefano Bianchi, Enrique García-Berro, Sandro Mereghetti, C. Guidorzi, C. Corral Van Damme, Søren Brandt, Francesco Tombesi, Felix Ryde, Didier Barret, Simon Vaughan, Marco Feroci, T. Di Salvo, C. van Baren, Angelo Antonelli, Marc Ribó, J. L. Atteia, P. Soleri, Alessio Trois, Silvia Zane, G. Mouret, Ersin Gogus, Emanuele Perinati, J. Coker, Piero Malcovati, V. Mangano, F. Jetter, P. Uter, P. Romano, M. Nowak, Roberto Turolla, Laura Tolos, Antonino D'Ai, Laura Alvarez, C. Amoros, Simone Scaringi, A. Possenti, David M. Smith, M. Falanga, A. Goldwurm, René Hudec, Ignacio Negueruela, M. van der Klis, Francesco Longo, José A. Pons, I. M. McHardy, R. Rohlfs, P. Cais, Luigi Stella, S. Di Cosimo, Antoine Rousseau, M. Ayre, M. Gschwender, D. Klochkov, Niels Lund, Chryssa Kouveliotou, P. Azzarello, F. Château, Michael Gabler, S. Vercellone, Martin Durant, I. Donnarumma, Giorgio Matt, Mauro Orlandini, P. Kaaret, Patrick Smith, P. T. O'Brien, A. Argan, M. Orienti, Marco Grassi, Claudio Labanti, Edward F. Brown, Christopher S. Reynolds, Gloria Sala, Y. Evangelista, Gabriel Török, José Braga, Riccardo Campana, Alan Smith, C. Gouiffes, Nevin N. Weinberg, Leonardo Gualtieri, Yannick Favre, P.G. Jonker, Gabriele Giovannini, D. de Martino, Irfan Kuvvetli, S. Motta, Teresa Mineo, Paul J. Groot, Pablo Reig, Martino Marisaldi, Andrea Sanna, Lorenzo Amati, G. L. Israel, D. Macera, K. S. Wood, Pablo Cerdá-Durán, F. Fuschino, Suvi Gezari, Mariano Mendez, Slawomir Suchy, Damien Rambaud, Nanda Rea, R. Artigue, J.-Y. Seyler, S. N. Shore, Frederick K. Lamb, Jörn Wilms, Mark G. Alford, Margarita Hernanz, Thomas M. Tauris, Luca Izzo, Tobias Boenke, J. J. M. in 't Zand, J. Mulačová, P. Binko, Daniel Maier, Jan Schee, Bruce Gendre, Enrico Bozzo, Paul S. Ray, Giuseppe Bertuccio, Simone Migliari, Ignazio Bombaci, Vladimir Karas, Nikolaos Stergioulas, P. P. Laubert, D. Karelin, A. C. Fabian, Giovanni Miniutti, Dacheng Lin, L. Guy, Martine Mouchet, Colleen A. Wilson-Hodge, Valeria Ferrari, Kai Hebeler, Mark H. Finger, Shigeto Watanabe, Pawel Haensel, H. Jacobs, Adrian Martindale, A. A. Zdziarski, Andrea Santangelo, Giuseppe Baldazzi, Piergiorgio Casella, Fabio Muleri, M. Hailey, Antonio Bianchini, Giuseppe Lodato, E. Del Monte, M. Rapisarda, Zdeněk Stuchlík, Alain Cros, V. Sochora, Laurens Keek, Jorge Casares, Andrew Melatos, Pere Blay, E. Rossi, A. P. Spencer, G. Stratta, Conrado Albertus, J. M. Paredes, M. Ahangarianabhari, Anna L. Watts, M. Del Santo, I. Kreykenbohm, Alessandro Patruno, G. A. Caliandro, C. Feldman, M. Pohl, Fabrizio Tamburini, G. Zampa, Marina Orio, Flemming Hansen, P. Ramon, Ruben Salvaterra, David H. Lumb, Edward M. Cackett, Andrew Shearer, Sharon M. Morsink, L. Pacciani, J.-M. Bonnet Bidaud, A. De Luca, Jérôme Chenevez, Sebastian Diebold, N. Zampa, Carole A. Haswell, Luciano Burderi, E. Cavazzuti, Adam Ingram, Dhiren Kataria, Berend Winter, A. Vacchi, W. Hermsen, P. Giommi, Dong Lai, N. A. Webb, P. Bodin, Dom Walton, Solen Balman, Benjamin Stappers, M. Burgay, Luca Zampieri, Carl Budtz-Jørgensen, Ralph A. M. J. Wijers, Giancarlo Cusumano, J. L. Galvez Sanchez, Raffaella Schneider, Luciano Rezzolla, Alexander Heger, S. Korpela, Dimitrios Emmanoulopoulos, Biswajit Paul, Diego Götz, B. Artigues, Paolo Soffitta, M. H. Finger, J. W. den Herder, Paolo Esposito, Kazushi Iwasawa, Poul Erik Holmdahl Olsen, J. Neilsen, Marco Barbera, Deepto Chakrabarty, R. A. Osten, M. Reina Aranda, A. J. Castro-Tirado, Andrea Tramacere, D. Haas, Johannes Dercksen, John A. Tomsick, A. V. Penacchioni, V. D'Elia, Alfonso Collura, Altan Baykal, P. Le Provost, S. Turriziani, Kostas D. Kokkotas, Duncan K. Galloway, Ron Remillard, Juhani Huovelin, Somak Bhattacharyya, Pavel Bakala, Phil Uttley, Richard E. Cole, Mahesh Prakash, L. Kuiper, T. Munoz-Darias, Diego F. Torres, S. Mahmoodifar, G. Ramsay, Andrew Norton, T. Kennedy, Achim Schwenk, L. Zdunik, A. B. Giles, Jerome Rodriguez, C. Motch, Ilya Mandel, Marcello Giroletti, Dimitrios Psaltis, J. Sandberg, Fiamma Capitanio, Remon Cornelisse, M. R. Gilfanov, Peggy Varniere, Franck Cadoux, Peter J. Wheatley, M. de Pasquale, Juri Poutanen, S. Maestre, A. Pellizzoni, Axel Schwope, Diego Altamirano, Piotr Orleanski, V. Vrba, Agata Różańska, Kateřina Goluchová, P. Rodríguez Gil, Niccolò Bucciantini, Stéphane Schanne, Carlo Ferrigno, Thomas J. Maccarone, H. Wende, Tod E. Strohmayer, Tadayuki Takahashi, Francois Lebrun, E. Kuulkers, Jeroen Homan, Maurizio Paolillo, M. A. Perez, J. P. Osborne, A. Alpar, Sanjay Reddy, G.W. Fraser, V. Sulemainov, D. Linder, L. Sabau-Graziati, A. Rachevski, Bing Zhang, Alessandro Papitto, C. Tenzer, Alex Markowitz, J. Portell, Roberto Mignani, Fabrizio Bocchino, Arnau Rios, R. de la Rie, M. Wille, A. de Rosa, Alessandro Riggio, M. Frericks, Andrew W. Steiner, Michal Bursa, Federico Bernardini, Jon M. Miller, W. Kluzniak, INAF - Osservatorio Astronomico di Roma ( OAR ), Istituto Nazionale di Astrofisica ( INAF ), Laboratoire d'Astrophysique de l'Observatoire Midi-Pyrénées ( LATT ), Université Paul Sabatier - Toulouse 3 ( UPS ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Observatoire Midi-Pyrénées ( OMP ) -Centre National de la Recherche Scientifique ( CNRS ), Variable Energy Cyclotron Centre, Institut Pasteur de Montevideo, Réseau International des Instituts Pasteur ( RIIP ) -Institut Pasteur de Montevideo, Mullard Space Science Laboratory ( MSSL ), University College of London [London] ( UCL ), FORMATION STELLAIRE 2014, Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux ( L3AB ), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -Observatoire aquitain des sciences de l'univers ( OASU ), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -Laboratoire d'Astrophysique de Bordeaux [Pessac] ( LAB ), Université de Bordeaux ( UB ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -Université de Bordeaux ( UB ), Instituto de Astrofísica de Andalucía ( IAA ), Consejo Superior de Investigaciones Científicas [Spain] ( CSIC ), Institut de Recherches sur les lois Fondamentales de l'Univers ( IRFU ), Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Université Paris-Saclay, Interactions et dynamique des environnements de surface ( IDES ), Université Paris-Sud - Paris 11 ( UP11 ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ), Licryl Laboratory ( CNR-IPCF UOS Cosenza ), University of Calabria, Laboratori Nazionali di Frascati ( LNF ), National Institute for Nuclear Physics ( INFN ), PCAS, Istituto di Astrofisica Spaziale e Fisica Cosmica - Milano ( IASF-MI ), AstroParticule et Cosmologie ( APC - UMR 7164 ), Centre National de la Recherche Scientifique ( CNRS ) -Institut National de Physique Nucléaire et de Physique des Particules du CNRS ( IN2P3 ) -Observatoire de Paris-Université Paris Diderot - Paris 7 ( UPD7 ) -Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ), Astrophysique Interactions Multi-échelles ( AIM - UMR 7158 - UMR E 9005 ), Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Paris Diderot - Paris 7 ( UPD7 ), Canada's National Laboratory for Particle and Nuclear Physics ( TRIUMF ), NRC, Dipartimento di Astronomia, Universita degli Studi di Bologna, Università di Bologna [Bologna] ( UNIBO ), Institut de recherches sur la catalyse et l'environnement de Lyon ( IRCELYON ), Université Claude Bernard Lyon 1 ( UCBL ), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique ( CNRS ), Laboratoire Univers et Théories ( LUTH ), Institut national des sciences de l'Univers ( INSU - CNRS ) -Observatoire de Paris-Université Paris Diderot - Paris 7 ( UPD7 ) -Centre National de la Recherche Scientifique ( CNRS ), Laboratoire de Spectrochimie Infrarouge et Raman - UMR 8516 ( LASIR ), Université de Lille-Centre National de la Recherche Scientifique ( CNRS ), Dipartimento di Scienze Fisiche [Naples], Università degli studi di Napoli Federico II, Energétique, propulsion, espace, environnement ( EPEE ), Université d'Orléans ( UO ) -Centre National de la Recherche Scientifique ( CNRS ), Department of Physics and Astronomy [Hanover], Dartmouth College [Hanover], Institut de recherche en astrophysique et planétologie ( IRAP ), Université Paul Sabatier - Toulouse 3 ( UPS ) -Observatoire Midi-Pyrénées ( OMP ) -Centre National de la Recherche Scientifique ( CNRS ), Laboratoire d’Optique Atmosphérique - UMR 8518 ( LOA ), Institut national des sciences de l'Univers ( INSU - CNRS ) -Université de Lille-Centre National de la Recherche Scientifique ( CNRS ), Institut de Biologie du Développement de Marseille ( IBDM ), Aix Marseille Université ( AMU ) -Institut National de la Santé et de la Recherche Médicale ( INSERM ) -Centre National de la Recherche Scientifique ( CNRS ), Universitat Politècnica de Catalunya [Barcelona] ( UPC ), INAF-IASF Milano, Climate and Environmental Physics [Bern], University of Bern, Centre National d'Etudes Spatiales ( CNES ), Institute of Geology, Eidgenössische Technische Hochschule [Zürich] ( ETH Zürich ), IEEC-CSIC, Universitat Autònoma de Barcelona [Barcelona] ( UAB ), MedisysResearch Lab ( Medisys ), Philips Research, European Space Astronomy Center ( ESAC ), European Space Agency ( ESA ), High Energy Astrophys. & Astropart. Phys (API, FNWI), INAF - Osservatorio Astronomico di Roma (OAR), Istituto Nazionale di Astrofisica (INAF), Laboratoire d'Astrophysique de l'Observatoire Midi-Pyrénées (LATT), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Réseau International des Instituts Pasteur (RIIP), Mullard Space Science Laboratory (MSSL), University College of London [London] (UCL), Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Interactions et dynamique des environnements de surface (IDES), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Licryl Laboratory (CNR-IPCF UOS Cosenza), Università della Calabria [Arcavacata di Rende] (Unical), Laboratori Nazionali di Frascati (LNF), Istituto Nazionale di Fisica Nucleare (INFN), Istituto di Astrofisica Spaziale e Fisica Cosmica - Milano (IASF-MI), AstroParticule et Cosmologie (APC (UMR_7164)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Canada's particle accelerator centre (TRIUMF), Alma Mater Studiorum Università di Bologna [Bologna] (UNIBO), Institut de recherches sur la catalyse et l'environnement de Lyon (IRCELYON), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Univers et Théories (LUTH (UMR_8102)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Laboratoire Avancé de Spectroscopie pour les Intéractions la Réactivité et l'Environnement - UMR 8516 (LASIRE), Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), University of Naples Federico II = Università degli studi di Napoli Federico II, Energétique, propulsion, espace, environnement (EPEE), Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), Institut de recherche en astrophysique et planétologie (IRAP), Laboratoire d’Optique Atmosphérique - UMR 8518 (LOA), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Institut de Biologie du Développement de Marseille (IBDM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Universitat Politècnica de Catalunya [Barcelona] (UPC), Climate and Environmental Physics [Bern] (CEP), Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE)-Universität Bern [Bern] (UNIBE), Centre National d'Études Spatiales [Toulouse] (CNES), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Universitat Autònoma de Barcelona (UAB), MedisysResearch Lab (Medisys), European Space Astronomy Centre (ESAC), Agence Spatiale Européenne = European Space Agency (ESA), SPIE, Takahashi, Tadayuki, Feroci M., Den Herder J.W., Bozzo E., Barret D., Brandt S., Hernanz M., Van Der Klis M., Pohl M., Santangelo A., Stella L., Watts A., Wilms J., Zane S., Ahangarianabhari M., Albertus C., Alford M., Alpar A., Altamirano D., Alvarez L., Amati L., Amoros C., Andersson N., Antonelli A., Argan A., Artigue R., Artigues B., Atteia J.-L., Azzarello P., Bakala P., Baldazzi G., Balman S., Barbera M., Van Baren C., Bhattacharyya S., Baykal A., Belloni T., Bernardini F., Bertuccio G., Bianchi S., Bianchini A., Binko P., Blay P., Bocchino F., Bodin P., Bombaci I., Bonnet Bidaud J.-M., Boutloukos S., Bradley L., Braga J., Brown E., Bucciantini N., Burderi L., Burgay M., Bursa M., Budtz-Jorgensen C., Cackett E., Cadoux F.R., Cais P., Caliandro G.A., Campana R., Campana S., Capitanio F., Casares J., Casella P., Castro-Tirado A.J., Cavazzuti E., Cerda-Duran P., Chakrabarty D., Chateau F., Chenevez J., Coker J., Cole R., Collura A., Cornelisse R., Courvoisier T., Cros A., Cumming A., Cusumano G., D'ai A., D'elia V., Del Monte E., De Luca A., De Martino D., Dercksen J.P.C., De Pasquale M., De Rosa A., Del Santo M., Di Cosimo S., Diebold S., Di Salvo T., Donnarumma I., Drago A., Durant M., Emmanoulopoulos D., Erkut M.H., Esposito P., Evangelista Y., Fabian A., Falanga M., Favre Y., Feldman C., Ferrari V., Ferrigno C., Finger M., Finger M.H., Fraser G.W., Frericks M., Fuschino F., Gabler M., Galloway D.K., Galvez Sanchez J.L., Garcia-Berro E., Gendre B., Gezari S., Giles A.B., Gilfanov M., Giommi P., Giovannini G., Giroletti M., Gogus E., Goldwurm A., Goluchova K., Gotz D., Gouiffes C., Grassi M., Groot P., Gschwender M., Gualtieri L., Guidorzi C., Guy L., Haas D., Haensel P., Hailey M., Hansen F., Hartmann D.H., Haswell C.A., Hebeler K., Heger A., Hermsen W., Homan J., Hornstrup A., Hudec R., Huovelin J., Ingram A., In't Zand J.J.M., Israel G., Iwasawa K., Izzo L., Jacobs H.M., Jetter F., Johannsen T., Jonker P., Jose J., Kaaret P., Kanbach G., Karas V., Karelin D., Kataria D., Keek L., Kennedy T., Klochkov D., Kluzniak W., Kokkotas K., Korpela S., Kouveliotou C., Kreykenbohm I., Kuiper L.M., Kuvvetli I., Labanti C., Lai D., Lamb F.K., Laubert P.P., Lebrun F., Lin D., Linder D., Lodato G., Longo F., Lund N., Maccarone T.J., Macera D., Maestre S., Mahmoodifar S., Maier D., Malcovati P., Mandel I., Mangano V., Manousakis A., Marisaldi M., Markowitz A., Martindale A., Matt G., Mchardy I.M., Melatos A., Mendez M., Mereghetti S., Michalska M., Migliari S., Mignani R., Miller M.C., Miller J.M., Mineo T., Miniutti G., Morsink S., Motch C., Motta S., Mouchet M., Mouret G., Mulaova J., Muleri F., Munoz-Darias T., Negueruela I., Neilsen J., Norton A.J., Nowak M., O'brien P., Olsen P.E.H., Orienti M., Orio M., Orlandini M., Orleaaski P., Osborne J.P., Osten R., Ozel F., Pacciani L., Paolillo M., Papitto A., Paredes J.M., Patruno A., Paul B., Perinati E., Pellizzoni A., Penacchioni A.V., Perez M.A., Petracek V., Pittori C., Pons J., Portell J., Possenti A., Poutanen J., Prakash M., Le Provost P., Psaltis D., Rambaud D., Ramon P., Ramsay G., Rapisarda M., Rachevski A., Rashevskaya I., Ray P.S., Rea N., Reddy S., Reig P., Reina Aranda M., Remillard R., Reynolds C., Rezzolla L., Ribo M., De La Rie R., Riggio A., Rios A., Rodriguez-Gil P., Rodriguez J., Rohlfs R., Romano P., Rossi E.M.R., Rozanska A., Rousseau A., Ryde F., Sabau-Graziati L., Sala G., Salvaterra R., Sanna A., Sandberg J., Scaringi S., Schanne S., Schee J., Schmid C., Shore S., Schneider R., Schwenk A., Schwope A.D., Seyler J.-Y., Shearer A., Smith A., Smith D.M., Smith P.J., Sochora V., Soffitta P., Soleri P., Spencer A., Stappers B., Steiner A.W., Stergioulas N., Stratta G., Strohmayer T.E., Stuchlik Z., Suchy S., Sulemainov V., Takahashi T., Tamburini F., Tauris T., Tenzer C., Tolos L., Tombesi F., Tomsick J., Torok G., Torrejon J.M., Torres D.F., Tramacere A., Trois A., Turolla R., Turriziani S., Uter P., Uttley P., Vacchi A., Varniere P., Vaughan S., Vercellone S., Vrba V., Walton D., Watanabe S., Wawrzaszek R., Webb N., Weinberg N., Wende H., Wheatley P., Wijers R., Wijnands R., Wille M., Wilson-Hodge C.A., Winter B., Wood K., Zampa G., Zampa N., Zampieri L., Zdunik L., Zdziarski A., Zhang B., Zwart F., Ayre M., Boenke T., Corral Van Damme C., Kuulkers E., Lumb D., Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7), Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Centrale Lille Institut (CLIL), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Universität Bern [Bern]-Universität Bern [Bern], European Space Agency (ESA), Feroci, M., den Herder, J., Bozzo, E., Barret, D., Brandt, S., Hernanz, M., van der Klis, M., Pohl, M., Santangelo, A., Stella, L., Watts, A., Wilms, J., Zane, S., Ahangarianabhari, M., Albertus, C., Alford, M., Alpar, A., Altamirano, D., Alvarez, L., Amati, L., Amoros, C., Andersson, N., Antonelli, A., Argan, A., Artigue, R., Artigues, B., Atteia, J., Azzarello, P., Bakala, P., Baldazzi, G., Balman, S., Barbera, M., van Baren, C., Bhattacharyya, S., Baykal, A., Belloni, T., Bernardini, F., Bertuccio, G., Bianchi, S., Bianchini, A., Binko, P., Blay, P., Bocchino, F., Bodin, P., Bombaci, I., Bonnet Bidaud, J., Boutloukos, S., Bradley, L., Braga, J., Brown, E., Bucciantini, N., Burderi, L., Burgay, M., Bursa, M., Budtz Jørgensen, C., Cackett, E., Cadoux, F., Caïs, P., Caliandro, G., Campana, R., Campana, S., Capitanio, F., Casares, J., Casella, P., Castro Tirado, A., Cavazzuti, E., Cerda Duran, P., Chakrabarty, D., Château, F., Chenevez, J., Coker, J., Cole, R., Collura, A., Cornelisse, R., Courvoisier, T., Cros, A., Cumming, A., Cusumano, G., D'Ai', A., D'Elia, V., Del Monte, E., de Luca, A., de Martino, D., Dercksen, J., de Pasquale, M., De Rosa, A., Del Santo, M., Di Cosimo, S., Diebold, S., DI SALVO, T., Donnarumma, I., Drago, A., Durant, M., Emmanoulopoulos, D., Erkut, M., Esposito, P., Evangelista, Y., Fabian, A., Falanga, M., Favre, Y., Feldman, C., Ferrari, V., Ferrigno, C., Finger, M., Fraser, G., Frericks, M., Fuschino, F., Gabler, M., Galloway, D., Galvez Sanchez, J., Garcia Berro, E., Gendre, B., Gezari, S., Giles, A., Gilfanov, M., Giommi, P., Giovannini, G., Giroletti, M., Gogus, E., Goldwurm, A., Goluchová, K., Götz, D., Gouiffes, C., Grassi, M., Groot, P., Gschwender, M., Gualtieri, L., Guidorzi, C., Guy, L., Haas, D., Haensel, P., Hailey, M., Hansen, F., Hartmann, D., Haswell, C., Hebeler, K., Heger, A., Hermsen, W., Homan, J., Hornstrup, A., Hudec, R., Huovelin, J., Ingram, A., In't Zand, J., Israel, G., Iwasawa, K., Izzo, L., Jacobs, H., Jetter, F., Johannsen, T., Jonker, P., Josè, J., Kaaret, P., Kanbach, G., Karas, V., Karelin, D., Kataria, D., Keek, L., Kennedy, T., Klochkov, D., Kluzniak, W., Kokkotas, K., Korpela, S., Kouveliotou, C., Kreykenbohm, I., Kuiper, L., Kuvvetli, I., Labanti, C., Lai, D., Lamb, F., Laubert, P., Lebrun, F., Lin, D., Linder, D., Lodato, G., Longo, F., Lund, N., Maccarone, T., Macera, D., Maestre, S., Mahmoodifar, S., Maier, D., Malcovati, P., Mandel, I., Mangano, V., Manousakis, A., Marisaldi, M., Markowitz, A., Martindale, A., Matt, G., Mchardy, I., Melatos, A., Mendez, M., Mereghetti, S., Michalska, M., Migliari, S., Mignani, R., Miller, M., Miller, J., Mineo, T., Miniutti, G., Morsink, S., Motch, C., Motta, S., Mouchet, M., Mouret, G., Mulačová, J., Muleri, F., Muñoz Darias, T., Negueruela, I., Neilsen, J., Norton, A., Nowak, M., O'Brien, P., Olsen, P., Orienti, M., Orio, M., Orlandini, M., Orleański, P., Osborne, J., Osten, R., Ozel, F., Pacciani, L., Paolillo, M., Papitto, A., Paredes, J., Patruno, A., Paul, B., Perinati, E., Pellizzoni, A., Penacchioni, A., Perez, M., Petracek, V., Pittori, C., Pons, J., Portell, J., Possenti, A., Poutanen, J., Prakash, M., Le Provost, P., Psaltis, D., Rambaud, D., Ramon, P., Ramsay, G., Rapisarda, M., Rachevski, A., Rashevskaya, I., Ray, P., Rea, N., Reddy, S., Reig, P., Reina Aranda, M., Remillard, R., Reynolds, C., Rezzolla, L., Ribo, M., de la Rie, R., Riggio, A., Rios, A., Rodríguez Gil, P., Rodriguez, J., Rohlfs, R., Romano, P., Rossi, E., Rozanska, A., Rousseau, A., Ryde, F., Sabau Graziati, L., Sala, G., Salvaterra, R., Sanna, A., Sandberg, J., Scaringi, S., Schanne, S., Schee, J., Schmid, C., Shore, S., Schneider, R., Schwenk, A., Schwope, A., Seyler, J., Shearer, A., Smith, A., Smith, D., Smith, P., Sochora, V., Soffitta, P., Soleri, P., Spencer, A., Stappers, B., Steiner, A., Stergioulas, N., Stratta, G., Strohmayer, T., Stuchlik, Z., Suchy, S., Sulemainov, V., Takahashi, T., Tamburini, F., Tauris, T., Tenzer, C., Tolos, L., Tombesi, F., Tomsick, J., Torok, G., Torrejon, J., Torres, D., Tramacere, A., Trois, A., Turolla, R., Turriziani, S., Uter, P., Uttley, P., Vacchi, A., Varniere, P., Vaughan, S., Vercellone, S., Vrba, V., Walton, D., Watanabe, S., Wawrzaszek, R., Webb, N., Weinberg, N., Wende, H., Wheatley, P., Wijers, R., Wijnands, R., Wille, M., Wilson Hodge, C., Winter, B., Wood, K., Zampa, G., Zampa, N., Zampieri, L., Zdunik, L., Zdziarski, A., Zhang, B., Zwart, F., Ayre, M., Boenke, T., Corral van Damme, C., Kuulkers, E., Lumb, D., Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), National Institute for Nuclear Physics (INFN), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7), Canada's National Laboratory for Particle and Nuclear Physics (TRIUMF), Università di Bologna [Bologna] (UNIBO), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Spectrochimie Infrarouge et Raman - UMR 8516 (LASIR), Centre National de la Recherche Scientifique (CNRS)-Université de Lille, Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Lille, Aix Marseille Université (AMU)-Collège de France (CdF)-Centre National de la Recherche Scientifique (CNRS), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology in Zürich [Zürich] (ETH Zürich), Universitat Autònoma de Barcelona [Barcelona] (UAB), Astronomy, den Herder, J. W., Atteia, J. L., Bonnet Bidaud, J. M., Cadoux, F. R., Cais, P., Caliandro, G. A., Castro Tirado, A. J., D'Aì, A., De Luca, A., De Martino, D., Dercksen, J. P. C., De Pasquale, M., Di Salvo, T., Erkut, M. H., Finger, M. H., Fraser, G. W., Galloway, D. K., Galvez Sanchez, J. L., Giles, A. B., Hartmann, D. H., Haswell, C. A., in't Zand, J. J. M., Jacobs, H. M., Kuiper, L. M., Lamb, F. K., Laubert, P. P., Maccarone, T. J., Mchardy, I. M., Miller, M. C., Miller, J. M., Norton, A. J., Olsen, P. E. H., Orleanski, P., Osborne, J. P., Paolillo, Maurizio, Paredes, J. M., Penacchioni, A. V., Perez, M. A., Ray, P. S., Rossi, E. M. R., Schwope, A. D., Seyler, J. Y., Smith, D. M., Smith, P. J., Steiner, A. W., Strohmayer, T. E., Torrejon, J. M., Torres, D. F., and Wilson Hodge, C. A.

Subjects
x-ray and γ-ray instrumentation, compact objects, microchannel plates, X-ray detectors, X-ray imaging, X-ray spectroscopy, X-ray timing, Electronic, Optical and Magnetic Materials, Condensed Matter Physics, Computer Science Applications1707 Computer Vision and Pattern Recognition, Applied Mathematics, Electrical and Electronic Engineering, Vision, Observatories, Field of view, 01 natural sciences, 7. Clean energy, neutron stars, Observatory, 010303 astronomy & astrophysics, Physics, Equipment and services, Astrophysics::Instrumentation and Methods for Astrophysics, Steradian, [ SDU.ASTR.IM ] Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], Astrophysics - Instrumentation and Methods for Astrophysics, X-ray detector, [PHYS.ASTR.IM]Physics [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], Cosmic Vision, Spectral resolution, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, NO, microchannel plate, Settore FIS/05 - Astronomia e Astrofisica, X-rays, compact object, 0103 physical sciences, Electronic, Optical and Magnetic Materials, Instrumentation and Methods for Astrophysics (astro-ph.IM), dense hadronic matter, Sensors, 010308 nuclear & particles physics, Astronomy, Accretion (astrophysics), [SDU.ASTR.IM]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], Neutron star, 13. Climate action, [ PHYS.ASTR.IM ] Physics [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], Gamma-ray burst, astro-ph.IM
Abstract

The Large Observatory For x-ray Timing (LOFT) was studied within ESA M3 Cosmic Vision framework and participated in the final down-selection for a launch slot in 2022-2024. Thanks to the unprecedented combination of effective area and spectral resolution of its main instrument, LOFT will study the behaviour of matter under extreme conditions, such as the strong gravitational field in the innermost regions of accretion flows close to black holes and neutron stars, and the supra-nuclear densities in the interior of neutron stars. The science payload is based on a Large Area Detector (LAD, 10 m 2 effective area, 2-30 keV, 240 eV spectral resolution, 1 deg collimated field of view) and a WideField Monitor (WFM, 2-50 keV, 4 steradian field of view, 1 arcmin source location accuracy, 300 eV spectral resolution). The WFM is equipped with an on-board system for bright events (e.g. GRB) localization. The trigger time and position of these events are broadcast to the ground within 30 s from discovery. In this paper we present the status of the mission at the end of its Phase A study., Proc. SPIE 9144, Space Telescopes and Instrumentation 2014: Ultraviolet to Gamma Ray, 91442T

Published
2014
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