Search

We investigate the diffractive gluon jet production in eletron-ion collisions at the energies of the EIC and the LHeC. In addition, the assumption that the diffractive mass is much bigger than the photon virtuality is taken, applying a model inspired in the GBW parametrization to describe the dipole amplitude. We show that the diffrative cross section is strongly sensitive to the saturation scale. Furthermore, we verify that it is possible to infer this scale from the experiment.

Charmed and beauty hadrons in matter are discussed within a unitarized coupled-channel model consistent with heavy-quark spin symmetry. We analyse the formation of D-mesic states as well as the propagation of charmed and beauty hadrons in heavy-ion collisions from LHC to FAIR energies., 10 pages, 6 figures, contribution based on an invited talk at the FIAS International Symposiom on Discoveries at the Frontiers of Science, June 26-30, 2017, FIAS (Germany)

The large time of life of $^{146} \mathrm{Sm}$ suggests the possibility to use this p - nuclide as astrophysical chronometer to study the geochemical galactic evolution. Due to the high temperature and large densities of gamma quanta, neutrons and protons in stellar environment $^{146} \mathrm{Sm}$ nucleus can be obtained in (γ,n), (n,2n), (p,2n) processes on $^{146} \mathrm{Sm}$ .The knowledge of corresponding cross sections of gamma rays, neutrons and alpha induced processes is of a great importance for the explanation of ($^{146} \mathrm{Sm}$ /$^{144} \mathrm{Sm}$ ) ratio uncertainties observed on the Earth, meteorites, Moon and other celestial bodies.Cross sections of (γ,n), (n,2n), (α,γ) processes induced by fast gamma rays, neutrons and alphas on $^{147} \mathrm{Sm}$ and $^{142} \mathrm{Nd}$ from threshold up to 25 MeV were evaluated and predicted in the frame of Hauser-Feshbach statistical model by using Talys software and the own computer programs. For each nuclear reaction contribution of direct, compound and pre-equilibrium mechanisms were determined. Theoretical evaluations are compared with existing experimental data. Parameters of optical potential in the incident and emergent channels and of nuclear densities were extracted. Calculated cross sections together with corresponding nuclear data were used in the evaluation of astrophysical rates necessary in the determination of elemental abundances as needed by nuclear astrophysical networks.

Two new bands have been identified in $^{137}$Nd from a high-statistics JUROGAM II gamma-ray spectroscopy experiment. Constrained density functional theory and particle rotor model calculations are used to assign configurations and investigate the band properties, which are well described and understood. It is demonstrated that these two new bands can be interpreted as chiral partners of previously known three-quasiparticle positive- and negative-parity bands. The newly observed chiral doublet bands in $^{137}$Nd represent an important support to the existence of multiple chiral bands in nuclei. The present results constitute the missing stone in the series of Nd nuclei showing multiple chiral bands, which becomes the most extended sequence of odd–even and even-even nuclei presenting multiple chiral bands in the Segré chart. Two new bands have been identified in $^{137}$Nd from a high-statistics JUROGAM II gamma-ray spectroscopy experiment. Constrained density functional theory and particle rotor model calculations are used to assign configurations and investigate the band properties, which are well described and understood. It is demonstrated that these two new bands can be interpreted as chiral partners of previously known three-quasiparticle positive- and negative-parity bands. The newly observed chiral doublet bands in $^{137}$Nd represent an important support to the existence of multiple chiral bands in nuclei. The present results constitute the missing stone in the series of Nd nuclei showing multiple chiral bands, which becomes the most extended sequence of nuclei presenting multiple chiral bands in the Segr\'e chart.

The determination of the involved reaction cross sections is essential for the understanding of how the big bang nucleosynthesis and nuclear reactions in stars contribute to the observed abundances. One of those, which has not been measured so far, is the $^{10}\mathrm{Be(n,\gamma)}$ cross section. A $^{10}\mathrm{BeO}$ sample, provided by PSI Villigen, was irradiated in a cyclic activation at the TRIGA reactor in Mainz. The characteristic $\gamma$-rays following the decay of $^{11}\mathrm{Be}$ were measured using $\mathrm{LaBr_3}$ scintillation detectors. The thermal neutron cross section and the resonance integral were experimentally determined for the first time.

There is sparse direct experimental evidence that atomic nuclei can exhibit stable pear shapes arising from strong octupole correlations. In order to investigate the nature of octupole collectivity in radium isotopes, electric octupole ($E3$) matrix elements have been determined for transitions in $^{222,228}$Ra nuclei using the method of sub-barrier, multi-step Coulomb excitation. Beams of the radioactive radium isotopes were provided by the HIE-ISOLDE facility at CERN. The observed pattern of $E$3 matrix elements for different nuclear transitions is explained by describing $^{222}$Ra as pear-shaped with stable octupole deformation, while $^{228}$Ra behaves like an octupole vibrator. There is sparse direct experimental evidence that atomic nuclei can exhibit stable pear shapes arising from strong octupole correlations. In order to investigate the nature of octupole collectivity in radium isotopes, electric octupole ($E3$) matrix elements have been determined for transitions in $^{222,228}$Ra nuclei using the method of sub-barrier, multi-step Coulomb excitation. Beams of the radioactive radium isotopes were provided by the HIE-ISOLDE facility at CERN. The observed pattern of $E$3 matrix elements for different nuclear transitions is explained by describing $^{222}$Ra as pear-shaped with stable octupole deformation, while $^{228}$Ra behaves like an octupole vibrator.

High quality nuclear data is the most fundamental underpinning for all neutron metrology applications. This paper describes the release of version II of the International Reactor Dosimetry and Fusion File (IRDFF-II) that contains a consistent set of nuclear data for fission and fusion neutron metrology applications up to 60~MeV neutron energy. The library is intended to support: a) applications in research reactors; b) safety and regulatory applications in the nuclear power generation in commercial fission reactors; and c) material damage studies in support of the research and development of advanced fusion concepts. The paper describes the contents of the library, documents the thorough verification process used in its preparation, and provides an extensive set of validation data gathered from a wide range of neutron benchmark fields. The new \mbox{IRDFF-II} library includes 119 metrology reactions, four cover material reactions to support self-shielding corrections, five metrology metrics used by the dosimetry community, and cumulative fission products yields for seven fission products in three different neutron energy regions. In support of characterizing the measurement of the residual nuclei from the dosimetry reactions and the fission product decay modes, the present document lists the recommended decay data, particle emission energies and probabilities for 68 activation products. It also includes neutron spectral characterization data for 29 neutron benchmark fields for the validation of the library contents. The IRDFF-II library and comprehensive documentation is available online at https://www-nds.iaea.org/IRDFF/. Evaluated cross sections can be compared with experimental data and other evaluations at https://www-nds.iaea.org/exfor/endf.htm. The new library is expected to become the international reference in neutron metrology for multiple applications., Submitted to Nuclear Data Sheets, 109 pages, figures revised

A Lattice QCD approach to quark orbital angular momentum in the proton based on generalized transverse momentum-dependent parton distributions (GTMDs) is enhanced methodologically by incorporating a direct derivative technique. This improvement removes a significant numerical bias that had been seen to afflict results of a previous study. In particular, the value obtained for Ji quark orbital angular momentum is reconciled with the one obtained independently via Ji's sum rule, validating the GMTD approach. Since GTMDs simultaneously contain information about the quark impact parameter and transverse momentum, they permit a direct evaluation of the cross product of the latter. They are defined through proton matrix elements of a quark bilocal operator containing a Wilson line; the choice in Wilson line path allows one to continuously interpolate from Ji to Jaffe-Manohar quark orbital angular momentum. The latter is seen to be significantly enhanced in magnitude compared to Ji quark orbital angular momentum, confirming previous results., Comment: 12 pages, 6 figures

This report summarizes the presentations and discussions during the Rapid Reaction Task Force "Dynamics of critical fluctuations: Theory -- phenomenology -- heavy-ion collisions", which was organized by the ExtreMe Matter Institute EMMI and held at GSI, Darmstadt, Germany in April 2019. We address the current understanding of the dynamics of critical fluctuations in QCD and their measurement in heavy-ion collision experiments. In addition, we outline what might be learned from studying correlations in other physical systems, such as cold atomic gases., 89 pages, 11 figures, report on an ExtreMe Matter Institute EMMI Rapid Reaction Task Force

In this talk, I give a brief overview of heavy ion physics. I discuss QCD dynamics at high energy and high part on density in a wide momentum range spanning collective dynamics in the soft sector to jet quenching at high momentum. I will also touch upon the physics of gluon saturation that will be probed at the future EIC.

We present a first step in developing a benchmark equation-of-state (EoS) model for multi-messenger astronomy that unifies the thermodynamics of quark and hadronic degrees of freedom. A Lagrangian approach to the thermodynamic potential of quark-meson-nucleon (QMN) matter was used. In this approach, dynamical chiral-symmetry breaking is described by the scalar mean-field dynamics coupled to quarks and nucleons and their chiral partners, whereby its restoration occurs in the hadronic phase by parity doubling, as well as in the quark phase. Quark confinement was achieved by an auxiliary scalar field that parametrizes a dynamical infrared cutoff in the quark sector, serving as an ultraviolet cutoff for the nucleonic phase space. The gap equations were solved for the isospin-symmetric case, as well as for neutron star (NS) conditions. We also calculated the mass-radius (MR) relation of NSs and their tidal deformability parameter. The obtained EoS is in accordance with nuclear matter properties at saturation density and with the flow constraint from heavy ion collision experiments. For isospin-asymmetric matter, a sequential occurrence of light quark flavors is obtained, allowing for a mixed phase of chirally-symmetric nucleonic matter with deconfined down quarks. The MR relations and TDs for compact stars fulfill the constraints from the latest astrophysical observations for PSR J0740+6620, PSR J0030+0451, and the NS merger GW170817, whereby the tension between the maximum mass and compactness constraints rather uniquely fixes the model parameters. The model predicts the existence of stars with a core of chirally restored but purely hadronic (confined) matter for masses beyond $1.8~M_\odot$. Stars with pure-quark matter cores are found to be unstable against the gravitational collapse. This instability is shifted to even higher densities if repulsive interactions between quarks are included., Comment: version accepted for publication in A&A

In these two lectures I review the basics of heavy-ion collisions at relativistic energies and the physics we can do with them. I aim to cover the basics on the kinematics and observables in heavy-ion collider experiments, the basics on the phenomenology of the nuclear matter phase diagram, some of the model building and simulations currently used in the heavy-ion physics community and a selected list of amazing phenomenological discoveries and predictions., Comment: These lectures were given at the 2019 CERN Latin-American School of High-Energy Physics in Cordoba, Argentina, 13 - 26 March 2019 and the notes have been submitted to proceedings of CLASHEP 2019. These lecture notes are based on previous Heavy-Ion and extreme QCD lectures given at CLASHEP by A. Ayala (2017), E. Fraga (2015) and J. Takahashi (2013)

The proton-proton ($pp$) collisions at the Large Hadron Collider (LHC), CERN, Switzerland has brought up new challenges and opportunities in understanding the experimental findings in contrast to the conventional lower energy $pp$ collisions. Usually $pp$ collisions are used as the baseline measurement at the GeV and TeV energies in order to understand a possible high density QCD medium formation in heavy-ion collisions. However, the TeV $pp$ collisions have created a new domain of research, where scientists have started observing heavy-ion-like features (signatures) in high-multiplicity $pp$ collisions. This warrants a relook into TeV $pp$ collisions, if at all QGP-droplets are produced in such collisions. In this presentation, I discuss some of the new findings and concepts emerging out in $pp$ collisions at the LHC energies along with some of the new emergent phenomena in particle production., 5 pages, 4-captioned figures, Presented in the plenary session of Workshop on Frontiers in High Energy Physics (FHEP-2019), Hyderabad, India (To appear in Springer Proc.)

The suppression and modification of high-energy objects, like jets, in heavy-ion collisions provide an important window to access the degrees of freedom of the quark-gluon plasma on different length scales. Despite increasingly precise and differential measurements of the properties of jets in heavy-ion collisions, however, it has remained challenging to use jets to make unambiguous and model-independent statements about the quark-gluon plasma. Here I will give a personal take on some origins of these challenges, including the difficulty of modelling and biases from jet selection that obfuscate the direct interpretation of jet modification measurements. I will discuss a few model studies that have helped to disentangle the source of non-intuitive effects in measurements, and finally highlight data-driven approaches as an interesting opportunity toward studying the quark-gluon plasma in a model-independent way using jets., Comment: 9 pages, 0 figures; proceedings of Hard Probes 2020

Heavy-ion collisions at relativistic energies probe matter at extreme conditions of temperatures and energy densities. The study of event-by-event fluctuations of experimental observables is crucial to probe the QCD phase transition, locate the critical point, and learn about the associated critical phenomena. At the critical point, all thermodynamic quantities behave anomalously. Fluctuation measurements provide access to thermodynamic response functions. We discuss the methods for obtaining the isothermal compressibility using particle multiplicity fluctuation, and specific heat using fluctuations in mean transverse momentum, temperature, and energy. Lattice QCD calculations have predicted non-monotonic behavior in the higher-order cumulants of conserved quantities at the critical point. Fluctuations in the multiplicity of charged to neutral particles have been measured to understand the formation of domains of disoriented chiral condensates. We review the recent fluctuation results as a function of collision centrality and energy from experiments at SPS, RHIC, and LHC. In addition, we propose to map the temperature fluctuations in eta-phi plane to probe local fluctuations of temperature and energy density., Comment: To appear in the proceedings of WWND 2020 conference, 12 pages, 14 figures

Physical review / D 103(9), 094512 (2021). doi:10.1103/PhysRevD.103.094512, The quasi-PDF approach provides a path to computing parton distribution functions (PDFs) using lattice QCD. This approach requires matrix elements of a power-divergent operator in a nucleon at high momentum and one generically expects discretization effects starting at first order in the lattice spacing $a$. Therefore, it is important to demonstrate that the continuum limit can be reliably taken and to understand the size and shape of lattice artifacts. In this work, we report a calculation of isovector unpolarized and helicity PDFs using lattice ensembles with $N_f=2+1+1$ Wilson twisted mass fermions, a pion mass of approximately 370 MeV, and three different lattice spacings. Our results show a significant dependence on $a$, and the continuum extrapolation produces a better agreement with phenomenology. The latter is particularly true for the antiquark distribution at small momentum fraction $x$, where the extrapolation changes its sign., Published by Inst., Melville, NY

To test the predictive power of ab initio nuclear structure theory, the lifetime of the second 2+ state in neutron-rich O20,τ(22+)=150−30+80fs, and an estimate for the lifetime of the second 2+ state in C16 have been obtained for the first time. The results were achieved via a novel Monte Carlo technique that allowed us to measure nuclear state lifetimes in the tens-to-hundreds of femtoseconds range by analyzing the Doppler-shifted γ-transition line shapes of products of low-energy transfer and deep-inelastic processes in the reaction O18(7.0MeV/u)+Ta181. The requested sensitivity could only be reached owing to the excellent performances of the Advanced γ-Tracking Array AGATA, coupled to the PARIS scintillator array and to the VAMOS++ magnetic spectrometer. The experimental lifetimes agree with predictions of ab initio calculations using two- and three-nucleon interactions, obtained with the valence-space in-medium similarity renormalization group for O20 and with the no-core shell model for C16. The present measurement shows the power of electromagnetic observables, determined with high-precision γ spectroscopy, to assess the quality of first-principles nuclear structure calculations, complementing common benchmarks based on nuclear energies. The proposed experimental approach will be essential for short lifetime measurements in unexplored regions of the nuclear chart, including r-process nuclei, when intense beams, produced by Isotope Separation On-Line (ISOL) techniques, become available. To test the predictive power of ab initio nuclear structure theory, the lifetime of the second 2+ state in neutron-rich 20O, tau(2+_2 ) = 150(+80-30) fs, and an estimate for the lifetime of the second 2+ state in 16C have been obtained, for the first time. The results were achieved via a novel Monte Carlo technique that allowed us to measure nuclear state lifetimes in the tens-to-hundreds femtoseconds range, by analyzing the Doppler-shifted gamma-transition line shapes of products of low-energy transfer and deep-inelastic processes in the reaction 18O (7.0 MeV/u) + 181Ta. The requested sensitivity could only be reached owing to the excellent performances of the AGATA gamma-tracking array, coupled to the PARIS scintillator array and to the VAMOS++ magnetic spectrometer. The experimental lifetimes agree with predictions of ab initio calculations using two- and three-nucleon interactions, obtained with the valence-space in-medium similarity renormalization group for 20O, and with the no-core shell model for 16C. The present measurement shows the power of electromagnetic observables, determined with high-precision gamma spectroscopy, to assess the quality of first-principles nuclear structure calculations, complementing common benchmarks based on nuclear energies. The proposed experimental approach will be essential for short lifetimes measurements in unexplored regions of the nuclear chart, including r-process nuclei, when intense ISOL-type beams become available.

In modern nuclear physics, a special group of nuclei located close to the drip line named halo nuclei has received tremendous attention due to their unique cluster structure. These nuclei exhibit large matter radii and are qualitatively described as a compact core surrounded by a diffuse halo which is formed by the loosely-bound valence nucleon(s). Their existence breaks down the consistent predictions by the classical shell model and challenges nuclear-structure calculations. To understand this exotic feature from first principles, lots of efforts have been undertaken by nuclear physicists during the past decades. One of the most successful probes to look into these questions is the (d,p) transfer which has been proved to be a very powerful tool to extract single-particle properties of nuclei and hence is ideal to study one-neutron halo nuclei., The main topic of this work is to improve the reliability of the nuclear-structure observables extracted from transfer reactions. In one of our works [Phys. Rev. C 98, 054602 (2018)], the experiment done by Schmitt et al. on the $^{10}$Be(d,p)$^{11}$Be transfer reaction at four beam energies [Phys. Rev. Lett. 108, 192701 (2012)] is reanalyzed. In order to probe only the halo of the nucleus which is represented by the asymptotic normalization coefficient (ANC), the beam energy and angular ranges at which such reaction is strictly peripheral have to be determined. These peripheral conditions are systematically identified by coupling a Halo effective field theory (EFT) description of the $^{11}$Be nucleus at leading order (LO) with the adiabatic distorted wave approximation (ADWA) to model the transfer. The results suggest that focussing on the transfer data collected with low beam energies and at forward scattering angles ensures the peripherality of the reaction and hence is the best way to reliably extract the ANC. The resulting values of ANC are (0.785 ± 0.030) fm$^{-1/2}$ for the ground state and (0.135 ± 0.005) fm$^{-1/2}$ for the first excited state. These values are in excellent agreement with the values predicted by ab initio calculations (0.786 fm$^{-1/2}$ for the ground state and 0.129 fm$^{-1/2}$ for the excited state) [Phys. Rev. Lett. 117, 242501 (2016)]. An alternative way to explore the sensitivity of transfer calculations to the short-range physics of the $^{10}$Be-n wave function using Halo EFT is offered by the supersymmetry (SuSy) method. With this method, the SuSy partner of the original wave function can be generated which shares the same asymptotic behavior but exhibits a very different internal part. Feeding those wave functions into the transfer calculations, the results confirm the above findings with respect to the peripherality of the $^{10}$Be(d,p) transfer., This method has then been extended to study another one-neutron halo nucleus: $^{15}$C which is important in nuclear astrophysics. Its ANC is extracted from the cross sections of the $^{14}$C(d,p) transfer measured by Mukhamedzhanov et al. [Phys. Rev. C, 84, 024616 (2011)]. The values obtained are (1.26 ± 0.02) fm$^{-1/2}$ and (0.056 ± 0.001) fm$^{-1/2}$ for the ground state and first excited state of $^{15}$C, respectively. Especially for the ground state case, again, a perfect agreement is reached between our result and the one predicted by Navrátil et al. (C$_{1/2+}$ = 1.282 fm$^{-1/2}$) in an ab initio calculation. Relying on the inferred ANC value, it enables us to fit an effective $^{14}$C-n interaction at NLO in Halo EFT, which has been used later in other reaction calculations, such as Coulomb breakup and radiative capture [Phys. Rev. C 100, 044615 (2019)]. We have also looked at the extension of this idea to resonant states. After an analogous analysis using a bin description, it is figured out that the resonant width plays a key role in determining the magnitude of the cross sections for such transfers. Its effect on resonance can be comparable to that of the ANC on bound states. But the associated uncertainty is larger than that in the case of bound state., In collaboration with Prof. Obertelli, we have studied the potential use of sub-Coulomb (d,p) transfer to investigate the possible presence of a halo structure in the excitation spectrum of medium to heavy nuclei. Based on the hypothetical case of $^{95}$Sr, the dependencies of the transfer calculation on several crucial parameters including Q-value, nuclear spin and beam energy have been tested to understand better how the halo feature could be revealed by measuring transfer cross sections. The feasibility of this idea requires an accurate theoretical prediction and sensitive detection systems., On the experimental side, efforts have been made to progress in the data analysis of the IS561A experiment on $^{9}$Li(d,p) transfer performed at HIE-ISOLDE, CERN. Thanks to the preprocessing of the acquired data done by Jesper Halkjær Jensen (Aarhus), the necessary information on the elastic scattering channel ($^{9}$Li + d) has been successfully collected and matches well with our theoretical calculation. Due to some practical problems happening during the measurement which would propagate to the analysis and result in a low statistics, the extraction of the (d,p) channel will require further detailed analyses. To make up for this, the available data measured by Jeppesen et al. [Phys. Lett. B, 642(5): 449 – 454, 2006] and Cavallaro et al. [Phys. Rev. Lett. 118, 012701 (2017)] are taken into account to check in those cases the validity of the chosen model which has already been used to study the resonance of $^{11}$Be. The outcome suggests that the method we use is a fast and efficient option to simulate the resonance during the transfer. For the non-resonant part, choosing the prior form of the transition matrix instead of the post one is better suited., Doctorat en Sciences de l'ingénieur et technologie, info:eu-repo/semantics/nonPublished

Color reconnection (CR) mechanism in PYTHIA model has been reported to be essential to describe the flow-like collective effect observed in high multiplicity $p$+$p$ and $p$+Pb collisions. In this work, we test this mechanism towards explaining the Forward-Backward multiplicity correlation (b$_{\mathrm {cor}}$) measurements in $p$+$p$ collisions at the LHC energies. Out of the three different CR schemes implemented in PYTHIA, (a) MPI based CR (default mechanism), (b) QCD based CR and (c) Gluon moved CR, we found that the QCD based CR scheme describes relatively better the ALICE measurements of b$_{\mathrm {cor}}$ in $p$+$p$ collisions at $\sqrt{\mathrm s}$ = 0.9 and 7 TeV. In addition, we have tuned the parameters of the default CR mechanism in PYTHIA to describe simultaneously the measured charged particle multiplicity pseudo-rapidity ($\eta$) distribution and b$_{\mathrm {cor}}$. We found that an average number of multipartonic interactions ($\langle N_{\mathrm {MPI}} \rangle$) between 2.5 to 3 and CR range between 0.9 to 2.5 best describes the experimental data. Finally, we have presented a study using PYTHIA events for $p$+$p$ collisions at $\sqrt{\mathrm s}$ = 7 TeV which shows that the strength of Forward-Backward mean transverse momentum correlation (b$^{\langle p_{\mathrm{T}}\rangle \langle p_{\mathrm{T}} \rangle}_{\rm {cor}}$) is found to increase with CR in contrast to decrease of b$_{\rm {cor}}$ values with CR effect. Hence, simultaneously studying the b$^{\langle p_{\mathrm{T}}\rangle \langle p_{\mathrm{T}} \rangle}_{\rm {cor}}$ and b$_{\mathrm {\rm {cor}}}$ in the experiments will help in establishing the arguments either in favour or in disfavour of CR effect in the measurements.

We use experimentally measured identified particle spectra and Hanbury Brown-Twiss radii to determine the entropy per unit rapidity $dS/dy$ produced in $\sqrt{s} = 7$ TeV pp and $\sqrt{s_{\rm NN}} = 2.76$ TeV Pb-Pb collisions. We find that $dS/dy = 11335 \pm 1188$ in 0-10% Pb-Pb, $dS/dy = 135.7 \pm 17.9$ in high-multiplicity pp, and $dS/dy = 37.8 \pm 3.7$ in minimum bias pp collisions and compare the corresponding entropy per charged particle $(dS/dy)/(dN_{\rm ch}/dy)$ to predictions of statistical models. Finally, we use the QCD kinetic theory pre-equilibrium and viscous hydrodynamics to model entropy production in the collision and reconstruct the average temperature profile at $\tau_0 = 1$ fm/$c$ for high multiplicity pp and Pb-Pb collisions., Comment: 13 pages, 9 figures; added an appendix on relation between 1D and 3D HBT radii, updated references, small corrections, published version

This thesis presents nuclear spins, electromagnetic moments, and changes in the mean-square charge radii for radioactive gallium isotopes, and the latter two for the francium isotope $^{214}$Fr with additional $\alpha$-decay spectroscopy. Measurements were made using the CRIS technique at the ISOLDE facility in CERN, facilitating some of the most sensitive nuclear structure studies on exotic nuclei to date. Where applicable, experimental results are compared to empirical, and LSSM calculations. The amalgamated data set has presented the opportunity of probing the sturdiness of three doubly-magic nuclei with respect to their local vicinities: $^{56}$Ni, $^{78}$Ni, and $^{208}$Pb. A magical $^{56}$Ni core is confirmed with an electromagnetic-moment analysis of $^{65,67,69}$Ga, albeit of a soft nature. Comparisons with shell model calculations not only confirm increased mixtures of $\pi2p_{3/2}/\pi1f_{5/2}$ configurations and the presence of neutron correlations towards $N = 28$, but they also highlight systematic trends with respect to the neighbouring odd-$Z$ isotope chains. Analyses of neutron-rich species up to $^{82}$Ga reveal a rich collection of nuclear-structure effects: a gradual proton-occupation migration from $\pi2p_{3/2} \rightarrow \pi1f_{5/2}$ for the odd-$A$ species which culminates in a ground-state spin reversal involving those spins at $^{81}$Ga, isomeric presence in $^{80}$Ga at $N = 49$, and a kink in the change in the mean-square charge radii for $^{82}$Ga at $N = 51$. Overall, this adds further evidence for a robust doubly magic $^{78}$Ni core. Measurements of $^{214}$Fr with t$_{1/2} = 5$ ms represents the shortest-lived isotope to have been measured with laser spectroscopy techniques at an online facility, in which the ISOL production mechanism is the limiting factor. With its $g$ factor suggesting a relatively pure ($\pi1h_{9/2} \otimes \pi2g_{9/2}$) configuration for $I^{\pi} = 1^{−}$ and a kink in its charge-radii value at $N = 127$, the magical effects of $^{208}$Pb can be observed five protons away.

To study the microscopic structure of quark-gluon plasma, data from hadronic collisions must be confronted with models that go beyond fluid dynamics. Here, we study a simple kinetic theory model that encompasses fluid dynamics but contains also particle-like excitations in a boost invariant setting with no symmetries in the transverse plane and with large initial momentum asymmetries. We determine the relative weight of fluid dynamical and particle like excitations as a function of system size and energy density by comparing kinetic transport to results from the 0th, 1st and 2nd order gradient expansion of viscous fluid dynamics. We then confront this kinetic theory with data on azimuthal flow coefficients over a wide centrality range in PbPb collisions at the LHC, in AuAu collisions at RHIC, and in pPb collisions at the LHC. Evidence is presented that non-hydrodynamic excitations make the dominant contribution to collective flow signals in pPb collisions at the LHC and contribute significantly to flow in peripheral nucleus-nucleus collisions, while fluid-like excitations dominate collectivity in central nucleus-nucleus collisions at collider energies., Comment: 28 pages, 16 figures

Measurements of atomic transitions in different isotopes offer key information on the nuclear charge radius. The anticipated high-precision experimental techniques, augmented by atomic calculations, will soon enable extraction of the higher order radial moments of the charge density distribution. To assess the value of such measurements for nuclear structure research, we study the information content of the fourth radial moment ⟨r^{4}⟩ by means of nuclear density functional theory and a multiple correlation analysis. We show that ⟨r^{4}⟩ can be directly related to the surface thickness of nuclear density, a fundamental property of the atomic nucleus that is difficult to obtain for radioactive systems. Precise knowledge of these radial moments is essential to establish reliable constraints on the existence of new forces from precision isotope shift measurements., US Department of Energy, Office of Science, Office of Nuclear Physics under Awards No. DE-SC0013365 (Michigan State University) and No. DE-SC0018083 (NU-CLEI SciDAC-4 Collaboration))

We investigate the forward-jet energy spectrum within the Color Glass Condensate framework at 5 TeV center-of-mass energy. In particular, we focus on the kinematic range covered by the CMS-CASTOR calorimeter. We show that our saturation-model calculations are compatible with the CASTOR measurements and that to optimally reproduce the data, effects of multi-parton interactions need to be included. We predict a significant nuclear suppression - reaching down to 50% at the lowest considered jet energies $E_{\rm jet} \sim 500 \, {\rm GeV}$., 13 pages, 9 figures

We performed state-of-the-art QCD effective kinetic theory simulations of chemically equilibrating QGP in longitudinally expanding systems. We find that chemical equilibration takes place after hydrodynamization, but well before local thermalization. By relating the transport properties of QGP and the system size we estimate that hadronic collisions with final state multiplicities $dN_\text{ch}/d��> 10^2$ live long enough to reach approximate chemical equilibrium for all collision systems. Therefore we expect the saturation of strangeness enhancement to occur at the same multiplicity in proton-proton, proton-nucleus and nucleus-nucleus collisions., 5 pages, 1 figure, proceedings for the XVIII International Conference on Strangeness in Quark Matter (SQM 2019), based on arXiv:1811.03040, arXiv:1811.03068

Understanding the origin and dynamics of hadron structure and in turn that of atomic nuclei is a central goal of nuclear physics. This challenge entails the questions of how does the roughly 1 GeV mass-scale that characterizes atomic nuclei appear; why does it have the observed value; and, enigmatically, why are the composite Nambu-Goldstone (NG) bosons in quantum chromodynamics (QCD) abnormally light in comparison? In this perspective, we provide an analysis of the mass budget of the pion and proton in QCD; discuss the special role of the kaon, which lies near the boundary between dominance of strong and Higgs mass-generation mechanisms; and explain the need for a coherent effort in QCD phenomenology and continuum calculations, in exa-scale computing as provided by lattice QCD, and in experiments to make progress in understanding the origins of hadron masses and the distribution of that mass within them. We compare the unique capabilities foreseen at the electron-ion collider (EIC) with those at the hadron-electron ring accelerator (HERA), the only previous electron-proton collider; and describe five key experimental measurements, enabled by the EIC and aimed at delivering fundamental insights that will generate concrete answers to the questions of how mass and structure arise in the pion and kaon, the Standard Model's NG modes, whose surprisingly low mass is critical to the evolution of our Universe., Comment: 16 pages, 12 figures, to appear in the European Physical Journal A - "Hadrons and Nuclei"

In this work, we use an extension of the quantization condition, given in Ref. [1], to numerically explore the finite-volume spectrum of three relativistic particles, in the case that two-particle subsets are either resonant or bound. The original form of the relativistic three-particle quantization condition was derived under a technical assumption on the two-particle K matrix that required the absence of two-particle bound states or narrow two-particle resonances. Here we describe how this restriction can be lifted in a simple way using the freedom in the definition of the K-matrix-like quantity that enters the quantization condition. With this in hand, we extend previous numerical studies of the quantization condition to explore the finite-volume signature for a variety of two- and three-particle interactions. We determine the spectrum for parameters such that the system contains both dimers (two-particle bound states) and one or more trimers (in which all three particles are bound), and also for cases where the two-particle subchannel is resonant. We also show how the quantization condition provides a tool for determining infinite-volume dimer-particle scattering amplitudes for energies below the dimer breakup. We illustrate this for a series of examples, including one that parallels physical deuteron-nucleon scattering. All calculations presented here are restricted to the case of three identical scalar particles., Comment: 42 pages, 16 figures, CERN-TH-2019-129, JLAB-THY-19-3011. Minor clarification and updated references

In this thesis, I present the results from three experiments studying the structure of $^{10}$Li through neutron transfer reactions at different beam energies. All three experiments were performed at the ISOLDE facility at CERN with a radioactive $^{9}$Li beam impinging on deuterated plastic. The results of the elastic channels are compared with OM and CDCC calculations. The result of the neutron transfer reactions is compared with CDCC calculations using a novel structure model of $^{10}$Li. The first experiment was carried out at 2.68 MeV/A in 2005 and give evidence for the existence of a virtual $s$$_{1/2}$ state in $^{10}$Li. Furthermore, it confirms the position of a $p$$_{1/2}$ resonance close to 0.5MeV. Coincidences between protons and $^{9}$Li, from the break up of $^{9}$Li, provides evidence for a sequential reaction model, however, the applied model can not account for the magnitude of the measured cross sections. In the second and third experiment at 6.72 MeV/A and 8.0 MeV/A, respectively, there are indications for a higher-lying $d$$_{5/2}$ resonance, however, this result is more speculative. The model also struggles to reproduce the absolute cross sections at these energies. Besides the results from the experiments, I present some of the technical methods that have been used and developed during the experiments and data analysis. This includes the data acquisition system and a general-purpose library for experiments with silicon detectors, AUSAlib. Moreover, the kinematic considerations that go into both the design and the analysis phase are discussed. Two techniques to determine beam properties are discussed. One is based on coincidences and mainly discussed through simulations whereas the other is based on only the ejectile of a two-body reaction. A Monte Carlo method for transforming measurements into absolute cross sections presented as well.

Recently, a framework has been developed to study form factors of two-hadron states probed by an external current. The method is based on relating finite-volume matrix elements, computed using numerical lattice QCD, to the corresponding infinite-volume observables. As the formalism is complicated, it is important to provide non-trivial checks on the final results and also to explore limiting cases in which more straightforward predications may be extracted. In this work we provide examples on both fronts. First, we show that, in the case of a conserved vector current, the formalism ensures that the finite-volume matrix element of the conserved charge is volume-independent and equal to the total charge of the two-particle state. Second, we study the implications for a two-particle bound state. We demonstrate that the infinite-volume limit reproduces the expected matrix element and derive the leading finite-volume corrections to this result for a scalar current. Finally, we provide numerical estimates for the expected size of volume effects in future lattice QCD calculations of the deuteron's scalar charge. We find that these effects completely dominate the infinite-volume result for realistic lattice volumes and that applying the present formalism, to analytically remove an infinite-series of leading volume corrections, is crucial to reliably extract the infinite-volume charge of the state., Comment: 20 pages, 5 figures

We analyse the azimuthal structure of two gluon correlations in the Color Glass Condensate including those effects that result from relaxing the shockwave approximation for the target. Working in the Glasma graph approach suitable for collisions between dilute systems, we compute numerically the azimuthal distributions and show that both even and odd harmonics appear. We study their dependence on model parameters, energy of the collision, pseudorapidity and transverse momentum of the produced particles, and length of the target. While the contribution from non-eikonal corrections vanishes with increasing collision energy and becomes negligible at the energies of the Large Hadron Collider, it is found to be sizeable up to top energies at the Relativistic Heavy Ion Collider., Comment: Latex, 18 pages, 7 figures; v2: 19 pages, 7 figures, some comments added and one figure modified, references updated, results and conclusions unchanged, final version

The observation of large azimuthal anisotropies $v_n$ in the particle spectra of proton-proton (pp) and proton-nucleus (pA) collisions challenges fluid dynamic interpretations of $v_n$, as it remains unclear how small collision systems can hydrodynamize and to what extent hydrodynamization is needed to build up $v_n$. Here, we study in a simple kinetic theory how the same physics that leads to hydrodynamization in large systems represents itself in small systems. We observe that one third to one half of the elliptic flow signal seen in fully hydrodynamized systems can be built up in collisions that extend over only one mean free path $l_{\rm mfp}$ and that do not hydrodynamize. This is qualitatively in line with observing a sizeable $v_2$ in $pp$ collisions for which other characteristics of soft multi-particle production seem well-described in a free-streaming picture. We further expose a significant system size dependence in the accuracy of hybrid approaches that match kinetic theory to viscous fluid dynamics. The implications of these findings for a reliable extraction of shear viscosity are discussed., 5 pages, 5 figures, version accepted for publication in EPJC

Proton-proton (pp) collisions have been traditionally used as a baseline measurement in the search for a deconfined state of matter in heavy-ion collisions at ultrarelativistic energies. The unprecedented collision energies that are available at the Large Hadron Collider (LHC) at the European Laboratory for Nuclear Research (CERN) have illuminated new challenges in understanding the possible formation of droplets of this deconfined matter of partonic degrees of freedom in hadronic collisions, especially in high-multiplicity events. Enhancement of multi-strange particles compared to pions, degree of collectivity, comparable freeze-out temperature with heavy-ion collisions, observation of a long-range ridge-like structure for high-multiplicity events are some of the experimental observations in this direction. In this article, we discuss some of the experimental observables and outline new theoretical directions to understand the possibilities of exploring the formation of QGP-droplets in pp collisions at the LHC., 6-pages, Featured invited article for beginners in the field, appeared in AAPPS Bulletin

In this report, I summarize the work conducted during my eight weeks as a summer student in the EN-STI-FLU department of CERN. The work focused on the benchmarking of FLUKA double differential cross sections of secondary fragments produced in fixed-target heavy ion collisions in the beam energy range between 10 MeV/nucleon and 1 GeV/nucleon. Specifically, the accuracy of FLUKA models for nucleus-nucleus interactions, namely the Boltzmann Master Equation (BME) and the relativistic Quantum Molecular Dynamics (rQMD) models, were analyzed. Furthermore, we compared the FLUKA production version 2011.2x.6 with the FLUKA development version 2018.2 and found that the latter is a considerable improvement to the former. Nevertheless, further improvements are required to better reproduce the experimental data. The major refinements needed are presented and discussed in this report.

The general-purpose code for the simulation of radiation transport FLUKA accounts for the elastic scattering of charged projectiles on the screened electrostatic potential of target atoms. However, no dedicated model for the nuclear elastic scattering of ions heavier than the proton is implemented. A prospective study has been carried out to examine the extent to which nuclear elastic scattering of alpha particles can be systematically modelled. In this work we have examined an effective optical potential model for the alpha-nucleus interaction, we have numerically solved the radial Schrodinger equation and we have evaluated the differential cross section for elastic scattering (DCES) using the partial-wave method. A preliminary database of DCES has been generated for alpha particles of up to 400 MeV on targets ranging from 12C to 209Bi for the sampling of nuclear elastic scattering events.

We investigate the observed pentaquark candidates $P_c(4312)$, $P_c(4440)$ and $P_c(4457)$ from the latest LHCb measurement, as well as four possible spin partners in the $\bar{D}^{(*)}\Sigma_c^*$ system predicted from the heavy quark spin symmetry with the hadronic molecule scenarios. Similar to the previous calculation on $P_c(4380)$ and $P_c(4450)$, the partial widths of all the allowed decay channels for these $P_c$ states are estimated with the effective Lagrangian method. The cutoff dependence of our numerical results are also presented. Comparing with the experimental widths, our results show that $P_c(4312)$, $P_c(4440)$ and $P_c(4457)$ can be described well with the spin-parity-$1/2^-$-$\bar{D}\Sigma_c$, $1/2^-$-$\bar{D}^*\Sigma_c$ and $3/2^-$-$\bar{D}^*\Sigma_c$ molecule pictures, respectively., Comment: 13 pages,8 figures

In the present work, we study the recent collision energy and multiplicity dependence of the charged particle transverse momentum spectra as measured by the ALICE collaboration in $pp$ collisions at $\sqrt{s}$ = 5.02 and 13 TeV using the non-extensive Tsallis distribution and the Boltzmann-Gibbs Blast Wave (BGBW) model. A thermodynamically consistent form of the Tsallis distribution is used to extract the kinetic freeze-out parameters from the transverse momentum spectra of charged particles at mid-rapidity. In addition, a comprehensive study of fitting range dependence of transverse momentum spectra on the freeze-out parameters is done using Tsallis statistics. The applicability of BGBW model is verified by fitting the transverse momentum spectra of the bulk part ($\sim 2.5~ {\rm GeV}/c$)for both 5.02 and 13 TeV energies and also in different multiplicity classes. The radial flow, $$ is almost independent of collision energy and multiplicity whereas the behavior of kinetic freeze-out temperature significantly depends on multiplicity classes. It is found that the Tsallis distribution generally leads to a better description for the complete transverse momentum spectra whereas the BGBW model explains the bulk part of the system., Comment: Same as the published version

We present a new approach to take into account resonance decays in the blast-wave model fits of identified hadron spectra. Thanks to pre-calculated decayed particle spectra, we are able to extract, in a matter of seconds, the multiplicity dependence of the single freeze-out temperature $T_{\rm fo}$, average fluid velocity $\left$, velocity exponent $n$, and the volume $dV/dy$ of an expanding fireball. In contrast to blast-wave fits without resonance feed-down, our approach results in a freeze-out temperature of $T_{\rm fo}\approx 150\,\text{MeV}$, which has only weak dependence on multiplicity and collision system. Finally, we discuss separate chemical and kinetic freeze-outs separated by partial chemical equilibrium., Comment: 8 pages, 6 figures; v2 analysis redone with PDG2016 resonance list, typos corrected, published version

Whether, how, and to what extent solutions of Bjorken-expanding systems become insensitive to aspects of their initial conditions is of importance for heavy-ion collisions. Here we study 1+1D and phenomenologically relevant boost-invariant 3+1D systems in which initial conditions approach a universal attractor. In Israel-Stewart theory (IS) and kinetic theory where the universal attractor extends to arbitrarily early times, we show that all initial conditions approach the attractor at early times by a power law while their approach is exponential at late times. In these theories, the physical mechanisms of hydrodynamization operational at late times do not drive the approach to the attractor at early times, and the early-time attractor is reached prior to hydrodynamization. In marked contrast, the attractor in strongly coupled systems is realized concurrent with hydrodynamization. This qualitative difference may offer a basis for discriminating weakly and strongly coupled scenarios of heavy-ion collisions. Whether, how, and to what extent solutions of Bjorken-expanding systems become insensitive to aspects of their initial conditions is of importance for heavy-ion collisions. Here we study 1+1D and phenomenologically relevant boost-invariant 3+1D systems in which initial conditions approach a universal attractor solution. In Israel-Stewart theory (IS) and kinetic theory where the universal attractor extends to arbitrarily early times, we show that all initial conditions approach the attractor at early times by a power-law while their approach is exponential at late times. In these theories, the physical mechanisms of hydrodynamization operational at late times do not drive the approach to the attractor at early times, and the early-time attractor is reached prior to hydrodynamization. In marked contrast, the attractor in strongly coupled systems is realized concurrent with hydrodynamization. This qualitative difference may offer a basis for discriminating weakly and strongly coupled scenarios of heavy-ion collisions.

Prompt double-$J/\psi$ production at high-energy hadron colliders can be considered as a golden channel to probe double parton scatterings (DPS) --in particular to study gluon-gluon correlations inside the proton-- and, at the same time, to measure the distribution of linearly-polarised gluons inside the proton. Such studies however require a good control of both single and DPS in the respective regions where they are carried out. In this context, we have critically examined two mechanisms of single parton scatterings (SPS) that may be kinematically enhanced where DPS are thought to be dominant, even though they are either at higher orders in the strong-coupling or velocity expansion. First, we have considered a gauge-invariant and infrared-safe subset of the loop-induced contribution via Colour-Singlet (CS) transitions. We have found it to become the leading CS SPS contributions at large rapidity separation, yet too small to account for the data without invoking the presence of DPS yields. Second, we have surveyed the possible Colour-Octet (CO) contributions using both old and up-to-date non-perturbative long distance matrix elements (LDMEs). We have found that the pure CO yields crucially depend on the LDMEs. Among all the LDMEs we used, only two result into a visible modification of the NRQCD (CS+CO) yield, but only in two kinematical distributions measured by ATLAS, those of the rapidity separation and of the pair invariant mass. These modifications however do not impact the control region used for their DPS study., Comment: 32 pages, 21 figures, 3 tables

Experimental measurements in pA collisions indicate no D meson suppression ($R_{\rm pPb} \sim 1$) but a surprisingly large $v_2$. To better understand these results we propose a system size scan at the LHC involving $^{16}$OO, $^{40}$ArAr, $^{129}$XeXe and $^{208}$PbPb collisions. Using Trento+ v-USPhydro+DAB-MOD to make predictions, we find that the $R_{\rm AA}$ tends towards unity when the system size is decreased, but nonetheless, in the most central collisions $v_2\{2\}$ is almost independent of the colliding system. These results are analyzed in light of path length and initial eccentricity variations., Comment: 4 pages, proceeding of Strangeness in Quark Matter (SQM 2019)

In recent years, different on-shell $\mathbf{3}\to\mathbf{3}$ scattering formalisms have been proposed to be applied to both lattice QCD and infinite volume scattering processes. We prove that the formulation in the infinite volume presented by Hansen and Sharpe in Phys.~Rev.~D92, 114509 (2015) and subsequently Brice\~no, Hansen, and Sharpe in Phys.~Rev.~D95, 074510 (2017) can be recovered from the $B$-matrix representation, derived on the basis of $S$-matrix unitarity, presented by Mai {\em et al.} in Eur.~Phys.~J.~A53, 177 (2017) and Jackura {\em et al.} in Eur.~Phys.~J.~C79, 56 (2019). Therefore, both formalisms in the infinite volume are equivalent and the physical content is identical. Additionally, the Faddeev equations are recovered in the non-relativistic limit of both representations., Comment: 13 pages, 5 figures

The transport coefficients of a multicomponent hadronic gas at zero and nonzero baryon chemical potential are calculated using the Chapman-Enskog method. The calculations are done within the framework of an S-matrix based interacting hadron resonance gas model. In this model, the phase shifts and cross sections are calculated using K-matrix formalism and where required, by parametrizing the experimental phase shifts. Using the energy dependence of the cross section, we find the temperature dependence of various transport coefficients such as shear viscosity, bulk viscosity, heat conductivity, and diffusion coefficient. We finally compare our results regarding various transport coefficients with previous results in the literature. The transport coefficients of a multi-component hadronic gas at zero and non-zero baryon chemical potential are calculated using the Chapman-Enskog method. The calculations are done within the framework of an $S$-matrix based interacting hadron resonance gas model. In this model, the phase-shifts and cross-sections are calculated using $K$-matrix formalism and where required, by parameterizing the experimental phase-shifts. Using the energy dependence of cross-section, we find the temperature dependence of various transport coefficients such as shear viscosity, bulk viscosity, heat conductivity and diffusion coefficient. We finally compare our results regarding various transport coefficients with previous results in the literature.

We derive a simple formula relating the cross section for light cluster production (defined via a coalescence factor) to the two-proton correlation function measured in heavy-ion collisions. The formula generalises earlier coalescence-correlation relations found by Scheibl & Heinz and by Mrowczynski for Gaussian source models. It motivates joint experimental analyses of Hanbury Brown-Twiss (HBT) and cluster yield measurements in existing and future data sets., 10 pages, 4 figures. v2: some clarifications. A missing (2\pi)^3 normalization factor, relating diff cross sec to density matrix traces, is corrected in Secs.II.A and II.B. It does not affect any of the results

Brambilla, Escobedo, Soto, and Vairo have derived an effective description of quarkonium with two parameters; a momentum diffusion term and a real self-energy term. We point out that the real self-energy term can be expressed directly in terms of Euclidean electric-field correlators along a Polyakov line. This quantity can be directly studied on the lattice without the need for analytical continuation. We show that existing Minkowski-space calculations of this correlator correspond with the known NLO Euclidean value of the relevant electric-field two-point function. Brambilla, Escobedo, Soto, and Vairo have derived an effective description of quarkonium with two parameters; a momentum diffusion term and a real self-energy term. We point out that there is a similar real self-energy term for a single open heavy flavor and that it can be expressed directly in terms of Euclidean electric field correlators along a Polyakov line. This quantity can be directly studied on the lattice without the need for analytical continuation. We show that Minkowski-space calculations of this correlator correspond with the known NLO Euclidean value of the relevant electric field two-point function and that it differs from the real self-energy term for quarkonium.

Within the DWBA framework, we develop a theoretical description of single and double heavy ion charge exchange (CE) reactions. We show that absorption effects are particularly important for heavy ion reactions, leading to a noticeable reduction of the CE cross sections. At low momentum transfer, the single CE cross section can be factorised, thus allowing to evaluate corresponding distortion factors and access beta decay strengths. Applications are shown for a system of experimental interest. Preliminary results are discussed also for double CE reactions, modeled as a two-step mechanisms, i.e. a sequence of two charge-changing processes., Proceedings of the 15th International Conference on Nuclear Reaction Mechanisms, Varenna (Italy), June 11-15, 2018 http://dx.doi.org/10.23727/CERN-Proceedings-2019-001

We consider an initially at rest colored particle which is struck by an ultra-relativistic nucleus. The particle is treated classically both with respect to its motion and its color charge. The nucleus is treated as a sheet of colored glass within the context of the Color Glass Condensate framework. We compute both the momentum and coordinates of the struck classical particle and the emitted radiation. Our computations generalize the classic electrodynamics computation of the radiation of an accelerated charged particle to include the radiation induced by the charged gluon field. This latter contribution adds to the classic electrodynamics result and produces a gluon rapidity distribution that is roughly constant as a function of rapidity at rapidities far from the fragmentation region of the struck particles. These computations may form the basis of a first principles treatment for the initial conditions for the evolution of matter produced in the fragmentation region of asymptotically high energy collisions., 26 pages, 3 figures

We discuss the prospects of performing high-order perturbative calculations in systems characterized by a vanishing temperature but finite density. In particular, we show that the determination of generic Feynman integrals containing fermionic chemical potentials can be reduced to the evaluation of three-dimensional phase space integrals over vacuum on-shell amplitudes - a result reminiscent of a previously proposed "naive real-time formalism" for vacuum diagrams. Applications of these rules are discussed in the context of the thermodynamics of cold and dense QCD, where it is argued that they facilitate an extension of the Equation of State of cold quark matter to higher perturbative orders., Comment: 22 pages, 3 figures; v2: discussion extended and references added

A new decay-spectroscopy station (DSS2.0) has been designed by the CRIS collaboration for use at the radioactive ion beam facility, ISOLDE. With the design optimised for both charged-particle and γ-ray detection, the DDS2.0 allows high-efficiency decay spectroscopy to be performed. The DSS2.0 complements the existing decay-spectroscopy system at the CRIS experiment, and together provide the ability to perform laser-assisted nuclear decay spectroscopy on both ground state and long-lived isomeric species. This paper describes the new decay-spectroscopy station and presents the characterisation studies that have recently been performed. publisher: Elsevier articletitle: A simple decay-spectroscopy station at CRIS-ISOLDE journaltitle: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment articlelink: http://dx.doi.org/10.1016/j.nima.2016.11.024 content_type: article copyright: © 2016 The Authors. Published by Elsevier B.V. ispartof: Nuclear Instruments & Methods in Physics Research A vol:844 pages:14-18 status: published

The Future Circular Collider is a new proposed collider at CERN with centre-of-mass energies around 100 TeV in the pp mode. Ongoing studies aim at assessing its physics potential and technical feasibility. Here we focus on updates in physics opportunities accessible in pA and AA collisions not covered in previous Quark Matter contributions, including Quark-Gluon Plasma and gluon saturation studies, novel hard probes of QCD matter, and photon-induced collisions., 4 pages, 5 figures, proceedings of Quark Matter 2015

Measurements of proton and nuclear collisions at the Large Hadron Collider at nucleon-nucleon c.m. energies up to $\sqrt{s_{NN}}=$ 13 TeV, have improved our understanding of hadronic interactions at the highest energies reached in collisions of cosmic rays with nuclei in the earth atmosphere, up to $\sqrt{s_{NN}}\approx 450$ TeV. The Monte Carlo event generators (EPOS, QGSJET, and SIBYLL) commonly used to describe the air showers generated by ultrahigh-energy cosmic rays (UHECR, with $E_{CR}\approx 10^{17}$--$10^{20}$ eV) feature now, after parameter retuning based on LHC Run-I data, more consistent predictions on the nature of the cosmic rays at the tail of the measured spectrum. However, anomalies persist in the data that cannot be accommodated by the models. Among others, the total number of muons (as well as their maximum production depth) remains significantly underestimated (overestimated) by all models. Comparisons of EPOS, QGSJET, and SIBYLL predictions to the latest LHC data, and to collider MC generators such as PYTHIA, indicate that improved description of hard multiple minijet production and nuclear effects may help reduce part of the data--model discrepancies, shed light on the UHECR composition approaching the observed $E_{CR}\approx 10^{20}$ eV cutoff, and uncover any potential new physics responsible of the observed anomalies., Minor text corrections. 6 pages, 10 figures. Proceedings of UHECR2018 (Paris). EDP WebOfConf to appear