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35 results on '"Aldo Antognini"'

1. Measuring the α-particle charge radius with muonic helium-4 ions

Author

Sandrine Galtier, Julian J. Krauth, Andreas Knecht, Andreas Dax, D. Taqqu, Thomas Graf, Paul Indelicato, Yi-Wei Liu, Karsten Schuhmann, Andreas Voss, F. Mulhauser, Pedro Amaro, Malte Hildebrandt, D. S. Covita, L.M.P. Fernandes, Boris Naar, F. D. Amaro, Theodor W. Hänsch, Marwan Abdou Ahmed, José Paulo Santos, Andrea L. Gouvea, Lucile Julien, Randolf Pohl, Johannes Götzfried, F. Nez, Beatrice Franke, Jorge Machado, Tobias Nebel, C.M.B. Monteiro, J.F.C.A. Veloso, Joaquim M. F. dos Santos, François Biraben, Franz Kottmann, Marc Diepold, Csilla I. Szabo, Jens Hartmann, Jan Vogelsang, Klaus Kirch, Aldo Antognini, Tzu-Ling Chen, Birgit Weichelt, LaserLaB Vrije Universiteit Amsterdam (LaserLaB), Vrije Universiteit Amsterdam [Amsterdam] (VU), Max-Planck-Institute for Quantum Optics, Institut für Physik [Mainz], Johannes Gutenberg - Universität Mainz (JGU), Institute for Particle Physics and Astrophysics [ETH Zürich] (IPA), Department of Physics [ETH Zürich] (D-PHYS), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich)- Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Paul Scherrer Institute (PSI), Institut für Strahlwerkzeuge, Universität of Stuttgart, Department of Physics [Coimbra], University of Coimbra [Portugal] (UC), Universidade Nova de Lisboa = NOVA University Lisbon (NOVA), Laboratoire Kastler Brossel (LKB [Collège de France]), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Collège de France (CdF (institution)), National Tsing Hua University [Hsinchu] (NTHU), Universidade de Aveiro, TRIUMF [Vancouver], Atmosphère, Optique et Spectroscopie (ATMOS), Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Ludwig-Maximilians-Universität München (LMU), Theiss Research, Lund University [Lund], Atoms, Molecules, Lasers, LaserLaB - Physics of Light, DF – Departamento de Física, and LIBPhys-UNL

Subjects
Physics, [PHYS]Physics [physics], Multidisciplinary, Muon, Proton, 010308 nuclear & particles physics, Nuclear structure, Atomic spectroscopy, Electron, 01 natural sciences, 7. Clean energy, Article, Ion, [SPI]Engineering Sciences [physics], Charge radius, 0103 physical sciences, [CHIM]Chemical Sciences, Physics::Atomic Physics, Exotic atoms and molecules, Atomic physics, Experimental nuclear physics, 010306 general physics, Spectroscopy, General
Abstract

The energy levels of hydrogen-like atomic systems can be calculated with great precision. Starting from their quantum mechanical solution, they have been refined over the years to include the electron spin, the relativistic and quantum field effects, and tiny energy shifts related to the complex structure of the nucleus. These energy shifts caused by the nuclear structure are vastly magnified in hydrogen-like systems formed by a negative muon and a nucleus, so spectroscopy of these muonic ions can be used to investigate the nuclear structure with high precision. Here we present the measurement of two 2S–2P transitions in the muonic helium-4 ion that yields a precise determination of the root-mean-square charge radius of the α particle of 1.67824(83) femtometres. This determination from atomic spectroscopy is in excellent agreement with the value from electron scattering1, but a factor of 4.8 more precise, providing a benchmark for few-nucleon theories, lattice quantum chromodynamics and electron scattering. This agreement also constrains several beyond-standard-model theories proposed to explain the proton-radius puzzle2,3,4,5, in line with recent determinations of the proton charge radius6,7,8,9, and establishes spectroscopy of light muonic atoms and ions as a precise tool for studies of nuclear properties., Nature, 589 (7843), ISSN:0028-0836, ISSN:1476-4687

Published
2021

2. Measurement of the quadrupole moment of Re185 and Re187 from the hyperfine structure of muonic X rays

Author

S. Roccia, Thomas Elias Cocolios, Natalia S. Oreshkina, Klaus Kirch, Angela Papa, Frederik Wauters, Andreas Knecht, Paul Indelicato, Rugard Dressler, Aldo Antognini, Randolf Pohl, Klaus-Peter Jungmann, Christoph H. Keitel, Nathal Severijns, Andreas Eggenberger, J. Nuber, E. Rapisarda, A. Ouf, Narongrit Ritjoho, S. M. Vogiatzi, Maxim Pospelov, Lorenz Willmann, Robert Eichler, Nathalie Michel, Niklaus Berger, and A. Skawran

Subjects
Physics, 010308 nuclear & particles physics, chemistry.chemical_element, High resolution, Germanium, Rhenium, 01 natural sciences, 7. Clean energy, chemistry, 0103 physical sciences, Quadrupole, Physics::Atomic Physics, Vacuum polarization, Atomic physics, 010306 general physics, Hyperfine structure
Abstract

The hyperfine splitting of the 5g→4f transitions in muonic Re185,187 has been measured using high resolution high purity germanium detectors and compared to state-of-the-art atomic theoretical predictions. The spectroscopic quadrupole moment has been extracted using modern fitting procedures and compared to the values available in literature obtained from muonic x rays of natural rhenium. The extracted values of the nuclear spectroscopic quadrupole moment are 2.07(5) b and 1.94(5) b, respectively for Re185 and Re187.

Published
2020

3. Demonstration of Muon-Beam Transverse Phase-Space Compression

Author

Andreas Eggenberger, K. S. Khaw, Florian M. Piegsa, Gunther Wichmann, Andreas Knecht, Ryoto Iwai, Narongrit Ritjoho, C. Petitjean, Angela Papa, Thomas J. Phillips, N. J. Ayres, V. Bondar, Klaus Kirch, Aldo Antognini, D. Taqqu, Daniel M. Kaplan, Ivana Belosevic, Alexey Stoykov, and Malte Hildebrandt

Subjects
Physics, Accelerator Physics (physics.acc-ph), Muon, Density gradient, 010308 nuclear & particles physics, Muonium, General Physics and Astronomy, FOS: Physical sciences, 01 natural sciences, Magnetic field, Transverse plane, Compression (functional analysis), Phase space, 0103 physical sciences, Physics::Accelerator Physics, Physics - Accelerator Physics, Atomic physics, 010306 general physics, Beam (structure)
Abstract

We demonstrate efficient transverse compression of a 12.5 MeV/c muon beam stopped in a helium gas target featuring a vertical density gradient and crossed electric and magnetic fields. The muon stop distribution extending vertically over 14 mm was reduced to a 0.25 mm size (rms) within 3.5 μs. The simulation including cross sections for low-energy μ+-He elastic and charge exchange (μ+↔ muonium) collisions describes the measurements well. By combining the transverse compression stage with a previously demonstrated longitudinal compression stage, we can improve the phase space density of a μ+ beam by a factor of 1010 with 10−3 efficiency., Physical Review Letters, 125 (16), ISSN:0031-9007, ISSN:1079-7114

Published
2020

4. Theory of the n=2 levels in muonic deuterium

Author

Franz Kottmann, Julian J. Krauth, Aldo Antognini, Marc Diepold, Randolf Pohl, and Beatrice Franke

Subjects
Physics, Nuclear Theory, QED, Atomic Physics (physics.atom-ph), 010308 nuclear & particles physics, FOS: Physical sciences, General Physics and Astronomy, Muonic deuterium, 01 natural sciences, Lamb shift, Physics - Atomic Physics, Nuclear Theory (nucl-th), Deuterium, Charge radius, 0103 physical sciences, Fine structure, Hyperfine structure, Physics::Atomic Physics, Atomic physics, 010306 general physics, Proton radius puzzle
Abstract

The present knowledge of Lamb shift, fine- and hyperfine structure of the $\mathrm{2S}$ and $\mathrm{2P}$ states in muonic deuterium is reviewed in anticipation of the results of a first measurement of several $\mathrm{2S-2P}$ transition frequencies in muonic deuterium ($\mu\mathrm{d}$). A term-by-term comparison of all available sources reveals reliable values and uncertainties of the QED and nuclear structure-dependent contributions to the Lamb shift, which are essential for a determination of the deuteron rms charge radius from $\mu\mathrm{d}$. Apparent discrepancies between different sources are resolved, in particular for the difficult two-photon exchange contributions. Problematic single-sourced terms are identified which require independent recalculation., Comment: 26 pages, add missing feynman diagrams (Fig. 3), renumber items (Tab. IV), correct a sum (column 5, Tab. IV)

Published
2016

5. Theory of the Lamb Shift and fine structure in muonic 4He ions and the muonic 3He– 4He Isotope Shift

Author

Franz Kottmann, Aldo Antognini, Marc Diepold, Beatrice Franke, Randolf Pohl, and Julian J. Krauth

Subjects
Muonic atoms/ions, Helium, Isotope shift, Nuclear structures, Fine structure, Lamb shift, Muonic atoms, Muonic ions, General Physics and Astronomy, 7. Clean energy, 01 natural sciences, Ion, Charge radius, 0103 physical sciences, Physics::Atomic and Molecular Clusters, Physics::Atomic Physics, Nuclear structure, SDG 7 - Affordable and Clean Energy, 010306 general physics, Exotic atom, Physics, 010308 nuclear & particles physics, Electric form factor, Charge density, Alpha particle, Deuterium, Atomic physics
Abstract

We provide an up to date summary of the theory contributions to the 2S → 2P Lamb shift and the fine structure of the 2P state in the muonic helium ion ( μ 4 He ) + . This summary serves as the basis for the extraction of the alpha particle charge radius from the muonic helium Lamb shift measurements at the Paul Scherrer Institute, Switzerland. Individual theory contributions needed for a charge radius extraction are compared and compiled into a consistent summary. The influence of the alpha particle charge distribution on the elastic two-photon exchange is studied to take into account possible model-dependencies of the energy levels on the electric form factor of the nucleus. We also discuss the theory uncertainty which enters the extraction of the 3He–4He isotope shift from the muonic measurements. The theory uncertainty of the extraction is much smaller than a present discrepancy between previous isotope shift measurements. This work completes our series of n = 2 theory compilations in light muonic atoms which we have performed already for muonic hydrogen, deuterium, and helium-3 ions.

Published
2018

6. The next generation of laser spectroscopy experiments using light muonic atoms

Author

M. Abdou Ahmed, J.F.C.A. Veloso, M. Willig, D. N. Patel, Laura Sinkunaite, Malte Hildebrandt, R. Horn, Jonas Nuber, José Paulo Santos, Li-Bang Wang, Andrzej Adamczak, Klaus Kirch, Stefan E. Schmidt, Miroslaw Marszalek, Jorge Machado, J. Haack, L.M.P. Fernandes, Karsten Schuhmann, Aldo Antognini, Jow-Tsong Shy, François Biraben, P. A. O. C. Silva, Pedro Amaro, Manuel Zeyen, Andreas Knecht, Patrícia Miguel da Silva Carvalho, Yi-Wei Liu, Tzu-Ling Chen, Paul Indelicato, C.M.B. Monteiro, Franz Kottmann, J.M.F. dos Santos, David Taqqu, Thomas Graf, Julian J. Krauth, F. D. Amaro, E. Rapisarda, François Nez, Yi-Jan Huang, Mauro Guerra, Randolf Pohl, Ivo Schulthess, Theodor W. Hänsch, Lucile Julien, Laboratoire Kastler Brossel (LKB [Collège de France]), Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris)-Collège de France (CdF)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Atoms, Molecules, Lasers, LaserLaB - Physics of Light, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Collège de France (CdF (institution))

Subjects
History, Atomic Physics (physics.atom-ph), measurement methods, chemistry.chemical_element, FOS: Physical sciences, 01 natural sciences, Effective nuclear charge, Education, Lamb shift, Physics - Atomic Physics, hydrogen: muonic atom, 0103 physical sciences, Physics::Atomic and Molecular Clusters, Physics::Atomic Physics, 010306 general physics, Spectroscopy, Helium, Exotic atom, Physics, [PHYS]Physics [physics], 010308 nuclear & particles physics, Precision spectroscopy, helium: muonic atom, nucleus, Nuclear structure, Fundamental interaction, [PHYS.PHYS.PHYS-GEN-PH]Physics [physics]/Physics [physics]/General Physics [physics.gen-ph], Computer Science Applications, laser, chemistry, charge radius, quantum electrodynamics: bound state, spectrometer, Atomic physics, experimental results
Abstract

Precision spectroscopy of light muonic atoms provides unique information about the atomic and nuclear structure of these systems and thus represents a way to access fundamental interactions, properties and constants. One application comprises the determination of absolute nuclear charge radii with unprecedented accuracy from measurements of the 2S - 2P Lamb shift. Here, we review recent results of nuclear charge radii extracted from muonic hydrogen and helium spectroscopy and present experiment proposals to access light muonic atoms with Z ≥ 3. In addition, our approaches towards a precise measurement of the Zemach radii in muonic hydrogen (μp) and helium (μ 3He+) are discussed. These results will provide new tests of bound-state quantum-electrodynamics in hydrogen-like systems and can be used as benchmarks for nuclear structure theories., Journal of Physics: Conference Series, 1138 (1), ISSN:1742-6588, ISSN:1742-6596

Published
2018

7. Theory of the n = 2 levels in muonic helium-3 ions

Author

Randolf Pohl, Julian J. Krauth, Marc Diepold, Franz Kottmann, Aldo Antognini, and Beatrice Franke

Subjects
Physics, Muon, Nuclear Theory, Atomic Physics (physics.atom-ph), 010308 nuclear & particles physics, Nuclear structure, FOS: Physical sciences, 01 natural sciences, Atomic and Molecular Physics, and Optics, Physics - Atomic Physics, Lamb shift, Nuclear Theory (nucl-th), Nuclear physics, Charge radius, Helium-3, 0103 physical sciences, Atomic Physics, Helion, Physics::Atomic Physics, 010306 general physics, Hyperfine structure, Exotic atom
Abstract

The present knowledge of Lamb shift, fine-, and hyperfine structure of the 2S and 2P states in muonic helium-3 ions is reviewed in anticipation of the results of a first measurement of several 2S → 2P transition frequencies in the muonic helium-3 ion, μ3He+. This ion is the bound state of a single negative muon μ- and a bare helium-3 nucleus (helion), 3He++. A term-by-term comparison of all available sources, including new, updated, and so far unpublished calculations, reveals reliable values and uncertainties of the QED and nuclear structure-dependent contributions to the Lamb shift and the hyperfine splitting. These values are essential for the determination of the helion rms charge radius and the nuclear structure effects to the hyperfine splitting in μ3He+. With this review we continue our series of theory summaries in light muonic atoms [see A. Antognini et al., Ann. Phys. 331, 127 (2013); J.J. Krauth et al., Ann. Phys. 366, 168 (2016); and M. Diepold et al. arXiv:1606.05231 (2016)]., The European Physical Journal D, 71 (12), ISSN:1434-6060, ISSN:1434-6079

Published
2017

8. Deuteron charge radius and Rydberg constant from spectroscopy data in atomic deuterium

Author

Randolf Pohl, Thomas Udem, François Nez, Axel Beyer, Julian J. Krauth, François Biraben, Lothar Maisenbacher, Arthur Matveev, Alexey Grinin, Lucile Julien, Theodor W. Hänsch, Aldo Antognini, Franz Kottmann, Hélène Fleurbaey, Atoms, Molecules, Lasers, LaserLaB - Physics of Light, Laboratoire Kastler Brossel (LKB [Collège de France]), Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris)-Collège de France (CdF)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Collège de France (CdF (institution)), Laboratoire Kastler Brossel ( LKB (Lhomond) ), Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris ( FRDPENS ), and Centre National de la Recherche Scientifique ( CNRS ) -École normale supérieure - Paris ( ENS Paris ) -Centre National de la Recherche Scientifique ( CNRS ) -École normale supérieure - Paris ( ENS Paris ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Centre National de la Recherche Scientifique ( CNRS )

Subjects
Hydrogen, Proton, Atomic Physics (physics.atom-ph), Physical constant, FOS: Physical sciences, chemistry.chemical_element, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, 7. Clean energy, Physics - Atomic Physics, Rydberg constant, Charge radius, 0103 physical sciences, [ PHYS.PHYS.PHYS-GEN-PH ] Physics [physics]/Physics [physics]/General Physics [physics.gen-ph], Physics::Atomic Physics, [ PHYS.NEXP ] Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Experiment (nucl-ex), 010306 general physics, Spectroscopy, Nuclear Experiment, Physics, proton radius, 010308 nuclear & particles physics, deuteron radius, General Engineering, Charge (physics), [PHYS.PHYS.PHYS-GEN-PH]Physics [physics]/Physics [physics]/General Physics [physics.gen-ph], 3. Good health, chemistry, Deuterium, Atomic physics
Abstract

We give a pedagogical description of the method to extract the charge radii and Rydberg constant from laser spectroscopy in regular hydrogen (H) and deuterium (D) atoms, that is part of the CODATA least-squares adjustment (LSA) of the fundamental physical constants. We give a deuteron charge radius Rd from D spectroscopy alone of 2.1415(45) fm. This value is independent of the measurements that lead to the proton charge radius, and five times more accurate than the value found in the CODATA Adjustment 10. The improvement is due to the use of a value for the 1S->2S transition in atomic deuterium which can be inferred from published data or found in a PhD thesis., 9 pages, 7 Tables and 3 Figures. Values of the Rydberg constant and discussion of the deuteron structure radius added

Published
2017

9. Laser spectroscopy of muonic hydrogen

Author

F. Mulhauser, F. D. Amaro, David Taqqu, Lucile Julien, Theodor W. Hänsch, Thomas Graf, Lukas A. Schaller, Randolf Pohl, Karsten Schuhmann, Joaquim M. F. dos Santos, Yi-Wei Liu, Andrea L. Gouvea, Aldo Antognini, Catherine Schwob, F. Biraben, Franz Kottmann, Cheng-Yang Kao, J. A. M. Lopes, D. S. Covita, Eric-Olivier Le Bigot, Tobias Nebel, Paul Indelicato, Livia Ludhova, J.F.C.A. Veloso, Satish Dhawan, João Cardoso, Marc Diepold, Jan Vogelsang, François Nez, Paul Rabinowitz, Adolf Giesen, Paul E. Knowles, C.M.B. Monteiro, Andreas Dax, and L.M.P. Fernandes

Subjects
Physics, General Physics and Astronomy, Laser, 01 natural sciences, 3. Good health, 010305 fluids & plasmas, law.invention, Lamb shift, Rydberg constant, Charge radius, law, 0103 physical sciences, Atomic physics, 010306 general physics, Spectroscopy, Hyperfine structure, Exotic atom
Abstract

We present here a discussion about the physics motivations and the experimental feasibility of our recent experimental proposal “Spectroscopy of Muonic Hydrogen” presented to the Dec. 1991 meeting of the PSI Benutzervesammlung (proposal R-9206–1).

Published
2013

10. Theory of the 2S–2P Lamb shift and 2S hyperfine splitting in muonic hydrogen

Author

Randolf Pohl, Aldo Antognini, François Nez, François Biraben, Franz Kottmann, and Paul Indelicato

Subjects
Physics, Proton, Hydrogen, Atomic Physics (physics.atom-ph), 010308 nuclear & particles physics, FOS: Physical sciences, General Physics and Astronomy, chemistry.chemical_element, Charge (physics), 01 natural sciences, Physics - Atomic Physics, Lamb shift, chemistry, Charge radius, 0103 physical sciences, Physics::Atomic Physics, Atomic physics, 010306 general physics, Spectroscopy, Hyperfine structure, Exotic atom
Abstract

The 7 standard deviations between the proton rms charge radius from muonic hydrogen and the CODATA-10 value from hydrogen spectroscopy and electron-scattering has caused considerable discussions. Here, we review the theory of the 2S-2P Lamb shift and 2S hyperfine splitting in muonic hydrogen combining the published contributions and theoretical approaches. The prediction of these quantities is necessary for the determination of both proton charge and Zemach radii from the two 2S-2P transition frequencies measured in muonic hydrogen., Comment: 20 pages with 3 Tables summarising the contributions to the muonic hydrogen Lamb shift and hyperfine splitting

Published
2013

11. Spatial confinement of muonium atoms

Author

Zaher Salman, Laszlo Liszkay, K. S. Khaw, Paolo Crivelli, Thomas Prokscha, Klaus Kirch, Aldo Antognini, 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 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
Atomic Physics (physics.atom-ph), measurement methods, Muonium, FOS: Physical sciences, Electron, 01 natural sciences, 7. Clean energy, 010305 fluids & plasmas, Physics - Atomic Physics, High Energy Physics - Experiment, High Energy Physics - Experiment (hep-ex), [ PHYS.HEXP ] Physics [physics]/High Energy Physics - Experiment [hep-ex], 0103 physical sciences, Bound state, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], [ PHYS.PHYS.PHYS-GEN-PH ] Physics [physics]/Physics [physics]/General Physics [physics.gen-ph], [PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], Physics::Atomic Physics, 010306 general physics, Spectroscopy, [ PHYS.PHYS.PHYS-INS-DET ] Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], Physics, muonium, Muon, Mesoporous silica, [PHYS.PHYS.PHYS-GEN-PH]Physics [physics]/Physics [physics]/General Physics [physics.gen-ph], laser, Reflection (mathematics), confinement, spectrometer, silicon: oxygen, atom: excited state, Atomic physics, Law of cosines
Abstract

We report the achievement of spatial confinement of muonium atoms (the bound state of a positive muon and an electron). Muonium emitted into vacuum from mesoporous silica reflects between two SiO$_2$ confining surfaces separated by 1 mm. From the data, one can extract that the reflection probability on the confining surfaces kept at 100 K is about 90% and the reflection process is well described by a cosine law. This technique enables new experiments with this exotic atomic system and is a very important step towards a measurement of the 1S-2S transition frequency using continuous wave laser spectroscopy., 5 pages, 6 figures

Published
2016

12. Experiments towards resolving the proton charge radius puzzle

Author

A. Knecht, José Paulo Santos, David Taqqu, Andreas Dax, Theodor W. Hänsch, Thomas Graf, Jorge Machado, Randolf Pohl, L.M.P. Fernandes, Marc Diepold, Françoise Mulhauser, F. D. Amaro, B. Franke, Malte Hildebrandt, Karsten Schuhmann, A. L. Gouvea, Pedro Amaro, Paul Indelicato, Yi-Wei Liu, Julian J. Krauth, C.M.B. Monteiro, S. Galtier, M. Abdou-Ahmed, L. Julien, D. S. Covita, Klaus Kirch, Aldo Antognini, J.F.C.A. Veloso, Csilla I. Szabo, Birgit Weichelt, J.M.F. dos Santos, Andreas Voss, Tzu-Ling Chen, François Nez, Franz Kottmann, François Biraben, Johannes Götzfried, Atoms, Molecules, Lasers, LaserLaB - Physics of Light, Elster, Charlotte, Phillips, Daniel R., Roberts, Craig, LIBPhys-UNL, and DF – Departamento de Física

Subjects
Hydrogen, Proton, POLARIZABILITY CONTRIBUTION, Atomic Physics (physics.atom-ph), QC1-999, chemistry.chemical_element, FOS: Physical sciences, MUONIC-HYDROGEN, Physics and Astronomy(all), FREQUENCY, 01 natural sciences, CHIRAL PERTURBATION-THEORY, HYDROGEN LAMB SHIFT, Physics - Atomic Physics, ATOMS, Charge radius, 0103 physical sciences, Physics::Atomic Physics, SDG 7 - Affordable and Clean Energy, 010306 general physics, Spectroscopy, Exotic atom, Physics, 010308 nuclear & particles physics, Scattering, METROLOGY, chemistry, ELASTIC-SCATTERING, Atomic physics, TRANSITION
Abstract

We review the status of the proton charge radius puzzle. Emphasis is given to the various experiments initiated to resolve the conflict between the muonic hydrogen results and the results from scattering and regular hydrogen spectroscopy., EPJ Web of Conferences, 113, ISSN:2100-014X, ISSN:2101-6275

Published
2016

13. Laser Spectroscopy of Muonic Atoms and Ions

Author

C.M.B. Monteiro, Andreas Dax, F. D. Amaro, Julian J. Krauth, Catherine Schwob, Andrea L. Gouvea, Jose A. Matias Lopes, Malte Hildebrandt, Marwan Abdou Ahmed, François Nez, Yi-Wei Liu, Jorge Machado, Eric-Olivier Le Bigot, José Paulo Santos, Lucile Julien, Paul Indelicato, David Taqqu, Beatrice Franke, L.M.P. Fernandes, João Cardoso, Pedro Amaro, Andreas Knecht, Lukas A. Schaller, Joaquim M. F. dos Santos, Paul E. Knowles, Sandrine Galtier, Johannes Götzfried, Csilla I. Szabo, Thomas Graf, Karsten Schuhmann, Franz Kottmann, D. S. Covita, Adolf Giesen, Theodor W. Hänsch, Birgit Weichelt, Paul Rabinowitz, Livia Ludhova, Tobias Nebel, Marc Diepold, Françoise Mulhauser, Randolf Pohl, François Biraben, Klaus Kirch, Aldo Antognini, J.F.C.A. Veloso, Satish Dhawan, Andreas Voss, Laboratoire Kastler Brossel (LKB [Collège de France]), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Collège de France (CdF (institution)), Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris)-Collège de France (CdF)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Kastler Brossel ( LKB (Lhomond) ), Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris ( FRDPENS ), and Centre National de la Recherche Scientifique ( CNRS ) -École normale supérieure - Paris ( ENS Paris ) -Centre National de la Recherche Scientifique ( CNRS ) -École normale supérieure - Paris ( ENS Paris ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Centre National de la Recherche Scientifique ( CNRS )

Subjects
deuteron, Proton, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], Atomic Physics (physics.atom-ph), muonic atoms, hyperfine structure, Nuclear Theory, FOS: Physical sciences, Molecular physics, 01 natural sciences, 7. Clean energy, 010305 fluids & plasmas, Ion, Physics - Atomic Physics, Lamb shift, Charge radius, Atom, 0103 physical sciences, Physics::Atomic and Molecular Clusters, [ PHYS.PHYS.PHYS-GEN-PH ] Physics [physics]/Physics [physics]/General Physics [physics.gen-ph], Physics::Atomic Physics, 010306 general physics, Spectroscopy, Nuclear Experiment, Hyperfine structure, [ PHYS.NUCL ] Physics [physics]/Nuclear Theory [nucl-th], Exotic atom, Physics, [PHYS]Physics [physics], Muon, [ PHYS ] Physics [physics], 010308 nuclear & particles physics, muonic atom, [PHYS.PHYS.PHYS-GEN-PH]Physics [physics]/Physics [physics]/General Physics [physics.gen-ph], laser, Deuterium, charge radius, laser spectroscopy, spectrometer, Atomic physics, proton
Abstract

Laser spectroscopy of the Lamb shift (2S-2P energy difference) in light muonic atoms or ions, in which one negative muon $\mu^-$ is bound to a nucleus, has been performed. The measurements yield significantly improved values of the root-mean-square charge radii of the nuclei, owing to the large muon mass, which results in a vastly increased muon wave function overlap with the nucleus. The values of the proton and deuteron radii are 10 and 3 times more accurate than the respective CODATA values, but 7 standard deviations smaller. Data on muonic helium-3 and -4 ions is being analyzed and will give new insights. In future, the (magnetic) Zemach radii of the proton and the helium-3 nuclei will be determined from laser spectroscopy of the 1S hyperfine splittings, and the Lamb shifts of muonic Li, Be and B can be used to improve the respective charge radii., Comment: Contribution to LEAP 2016 in Kanazawa, Japan

Published
2016

14. Laser spectroscopy of muonic deuterium

Author

Thomas Graf, L.M.P. Fernandes, Catherine Schwob, Lukas A. Schaller, Lucile Julien, David Taqqu, Paul Indelicato, F. D. Amaro, Franz Kottmann, Yi-Wei Liu, Joaquim M. F. dos Santos, François Nez, João Cardoso, F. Biraben, J.F.C.A. Veloso, Satish Dhawan, J. A. M. Lopes, Paul E. Knowles, Randolf Pohl, Tobias Nebel, D. S. Covita, Andrea L. Gouvea, F. Mulhauser, Karsten Schuhmann, Aldo Antognini, C.M.B. Monteiro, Andreas Dax, Paul Rabinowitz, Adolf Giesen, Eric-Olivier Le Bigot, Theodor W. Hänsch, Marc Diepold, Livia Ludhova, Laboratoire Kastler Brossel (LKB [Collège de France]), Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris)-Collège de France (CdF)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), CREMA, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Collège de France (CdF (institution))

Subjects
deuteron, atom: exotic, Proton, Nuclear Theory, 01 natural sciences, benchmark, hydrogen: muonic atom, Charge radius, muon, 0103 physical sciences, Neutron, Physics::Atomic Physics, 010306 general physics, Nuclear Experiment, deuterium, Exotic atom, Multidisciplinary, Muon, 010308 nuclear & particles physics, Chemistry, nuclear force, nucleus, transition, Radius, polarizability, [PHYS.PHYS.PHYS-GEN-PH]Physics [physics]/Physics [physics]/General Physics [physics.gen-ph], laser, Atomic radius, Deuterium, charge radius, Atomic physics
Abstract

The deuteron is too small, too The radius of the proton has remained a point of debate ever since the spectroscopy of muonic hydrogen indicated a large discrepancy from the previously accepted value. Pohl et al. add an important clue for solving this so-called proton radius puzzle. They determined the charge radius of the deuteron, a nucleus consisting of a proton and a neutron, from the transition frequencies in muonic deuterium. Mirroring the proton radius puzzle, the radius of the deuteron was several standard deviations smaller than the value inferred from previous spectroscopic measurements of electronic deuterium. This independent discrepancy points to experimental or theoretical error or even to physics beyond the standard model. Science , this issue p. 669

Published
2016

15. Laser spectroscopy of muonic deuterium: New contribution to the proton puzzle

Author

Theodor W. Hänsch, E.-O. Le Bigot, J. A. M. Lopes, Marc Diepold, Françoise Mulhauser, D. S. Covita, L.M.P. Fernandes, Th. Graf, João Cardoso, Franz Kottmann, Y. Wei Liu, Tobias Nebel, Lukas A. Schaller, Adolf Giesen, F. D. Amaro, Catherine Schwob, J.F.C.A. Veloso, F. Nez, Satish Dhawan, Livia Ludhova, David Taqqu, François Biraben, Karsten Schuhmann, Aldo Antognini, Paul Rabinowitz, Andrea L. Gouvea, J.M.F. dos Santos, Randolf Pohl, Lucile Julien, Paul E. Knowles, Paul Indelicato, C.M.B. Monteiro, and Andreas Dax

Subjects
Physics, Proton, Nuclear structure, 02 engineering and technology, 01 natural sciences, Lamb shift, Nuclear physics, 020210 optoelectronics & photonics, Rydberg constant, Deuterium, Charge radius, 0103 physical sciences, 0202 electrical engineering, electronic engineering, information engineering, Atomic physics, 010306 general physics, Spectroscopy, Exotic atom
Abstract

We report the first laser spectroscopy of muonic deuterium. At the Paul Scherrer Institute, we have measured the frequency of the 2S-2P Lamb shift in muonic deuterium. As in the case of the muonic hydrogen, the observed lines are shifted from the theoretical predictions. Thanks to improved new QED and nuclear structure calculations, an accurate determination of the deuteron radius can be extracted from our study. This determination will give a new and important input to the proton size puzzle.

Published
2016
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16. Muonic atoms and the nuclear structure

Author

Aldo Antognini

Subjects
Physics, Muon, Proton, Atomic Physics (physics.atom-ph), Nuclear Theory, Nuclear structure, FOS: Physical sciences, 020206 networking & telecommunications, 02 engineering and technology, Effective nuclear charge, Physics - Atomic Physics, Charge radius, 0202 electrical engineering, electronic engineering, information engineering, Physics::Atomic and Molecular Clusters, 020201 artificial intelligence & image processing, Physics::Atomic Physics, Atomic physics, Spectroscopy, Nuclear Experiment, Order of magnitude, Exotic atom
Abstract

High-precision laser spectroscopy of atomic energy levels enables the measurement of nuclear properties. Sensitivity to these properties is particularly enhanced in muonic atoms which are bound systems of a muon and a nucleus. Exemplary is the measurement of the proton charge radius from muonic hydrogen performed by the CREMA collaboration which resulted in an order of magnitude more precise charge radius as extracted from other methods but at a variance of 7 standard deviations. Here, we summarize the role of muonic atoms for the extraction of nuclear charge radii, we present the status of the so called "proton charge radius puzzle", and we sketch how muonic atoms can be used to infer also the magnetic nuclear radii, demonstrating again an interesting interplay between atomic and particle/nuclear physics., ICOLS 2015, Singapore. arXiv admin note: text overlap with arXiv:1509.03235

Published
2015

17. The Lamb shift in muonic hydrogenThis paper was presented at the International Conference on Precision Physics of Simple Atomic Systems, held at École de Physique, les Houches, France, 30 May – 4 June, 2010

Author

Randolf Pohl, Aldo Antognini, François Nez, Fernando D. Amaro, François Biraben, João M.R. Cardoso, Daniel S. Covita, Andreas Dax, Satish Dhawan, Luis M.P. Fernandes, Adolf Giesen, Thomas Graf, Theodor W. Hänsch, Paul Indelicato, Lucile Julien, Cheng-Yang Kao, Paul Knowles, Eric-Olivier Le Bigot, Yi-Wei Liu, José A.M. Lopes, Livia Ludhova, Cristina M.B. Monteiro, Françoise Mulhauser, Tobias Nebel, Paul Rabinowitz, Joaquim M.F. dos Santos, Lukas A. Schaller, Karsten Schuhmann, Catherine Schwob, David Taqqu, João F.C.A. Veloso, and Franz Kottmann

Subjects
Physics, Hydrogen, 010308 nuclear & particles physics, General Physics and Astronomy, chemistry.chemical_element, Spectral shift, 01 natural sciences, Lamb shift, chemistry, 0103 physical sciences, Atomic physics, 010306 general physics, Spectroscopy, Exotic atom
Abstract

The long quest for a measurement of the Lamb shift in muonic hydrogen is over. Last year we measured the 2S 1/2F=1 –2P 3/2F=2 energy splitting (Pohl et al., Nature, 466, 213 (2010)) in μp with an experimental accuracy of 15 ppm, twice better than our proposed goal. Using current QED calculations of the fine, hyperfine, QED, and finite size contributions, we obtain a root-mean-square proton charge radius of rp = 0.841 84 (67) fm. This value is 10 times more precise, but 5 standard deviations smaller, than the 2006 CODATA value of rp. The origin of this discrepancy is not known. Our measurement, together with precise measurements of the 1S–2S transition in regular hydrogen and deuterium, gives improved values of the Rydberg constant, R∞ = 10 973 731.568 160 (16) m–1 and the rms charge radius of the deuteron rd = 2.128 09 (31) fm.

Published
2011

18. Illuminating the proton radius conundrum: the μHe+ Lamb shiftThis paper was presented at the International Conference on Precision Physics of Simple Atomic Systems, held at École de Physique, les Houches, France, 30 May – 4 June, 2010

Author

J.M.F. dos Santos, L. Julien, A. Voss, F. Nez, Andreas Dax, Theodor W. Hänsch, Paul Indelicato, João Cardoso, François Biraben, L.M.P. Fernandes, F. Mulhauser, Andrea L. Gouvea, J.F.C.A. Veloso, Randolf Pohl, K. Schuhmann, Yi-Wei Liu, Klaus Kirch, Tobias Nebel, Aldo Antognini, Malte Hildebrandt, D. S. Covita, Th. Graf, D. Taqqu, F. Kottmann, and C.M.B. Monteiro

Subjects
Physics, 010308 nuclear & particles physics, Ab initio, General Physics and Astronomy, Radius, Polarization (waves), 7. Clean energy, 01 natural sciences, Charged particle, Lamb shift, Nuclear physics, Charge radius, 0103 physical sciences, Atomic physics, 010306 general physics, Spectroscopy, Hyperfine structure
Abstract

We plan to measure several 2S–2P transition frequencies in μ4He+ and μ3He+ by means of laser spectroscopy with an accuracy of 50 ppm. This will lead to a determination of the corresponding nuclear rms charge radii with a relative accuracy of 3 × 10−4, limited by the uncertainty of the nuclear polarization contribution. First, these measurements will help to solve the proton radius puzzle. Second, these very precise nuclear radii are benchmarks for ab initio few-nucleon theories and potentials. Finally when combined with an ongoing measurement of the 1S–2S transition in He+, these measurements will lead to an enhanced bound-state QED test of the 1S Lamb shift in He+.

Published
2011

19. Quantum interference shifts in laser spectroscopy with elliptical polarization

Author

Aldo Antognini, L. Safari, José Paulo Santos, Pedro Amaro, Paul Indelicato, F. Fratini, and Randolf Pohl

Subjects
Physics, Proton, Atomic Physics (physics.atom-ph), FOS: Physical sciences, Elliptical polarization, Laser, Atomic and Molecular Physics, and Optics, Physics - Atomic Physics, 3. Good health, law.invention, Deuterium, law, Quantum interference, Physics::Atomic Physics, Atomic physics, Spectroscopy, Circular polarization, Exotic atom
Abstract

We investigate the quantum interference shifts between energetically close states, where the state structure is observed by laser spectroscopy. We report a compact and analytical expression that models the quantum interference induced shift for any admixture of circular polarization of the incident laser and angle of observation. An experimental scenario free of quantum interference can thus be predicted with this formula. Although, this study is exemplified here for muonic deuterium, it can be applied to any other laser spectroscopy measurement of $ns-n'p$ frequencies of a nonrelativistic atomic system, via a $ns\rightarrow n'p \rightarrow n"s $ scheme., Comment: 5 pages 2 figs

Published
2015

20. Quantum interference effects in laser spectroscopy of muonic hydrogen, deuterium, and helium-3

Author

Pedro Amaro, Paul Indelicato, Franz Kottmann, Randolf Pohl, F. Fratini, Marc Diepold, L. Safari, Aldo Antognini, Jorge Machado, José Paulo Santos, Beatrice Franke, Julian J. Krauth, LIBPhys-UNL, DF – Departamento de Física, Atoms, Molecules, Lasers, and LaserLaB - Physics of Light

Subjects
IONS, Photon, Atomic Physics (physics.atom-ph), FOS: Physical sciences, LINE, FREQUENCY, PROTON, 7. Clean energy, 01 natural sciences, 010305 fluids & plasmas, Physics - Atomic Physics, Laser linewidth, LAMB-SHIFT, Helium-3, 0103 physical sciences, Physics::Atomic Physics, 010306 general physics, Spectroscopy, Hyperfine structure, NONRESONANT CORRECTIONS, Exotic atom, Physics, Atomic and Molecular Physics, and Optics, 3. Good health, Lamb shift, Deuterium, Atomic physics, 1S-2S TRANSITION
Abstract

Quantum interference between energetically close states is theoretically investigated, with the state structure being observed via laser spectroscopy. In this work, we focus on hyperfine states of selected hydrogenic muonic isotopes, and on how quantum interference affects the measured Lamb shift. The process of photon excitation and subsequent photon decay is implemented within the framework of nonrelativistic second-order perturbation theory. Due to its experimental interest, calculations are performed for muonic hydrogen, deuterium, and helium-3. We restrict our analysis to the case of photon scattering by incident linear polarized photons and the polarization of the scattered photons not being observed. We conclude that while quantum interference effects can be safely neglected in muonic hydrogen and helium-3, in the case of muonic deuterium there are resonances with close proximity, where quantum interference effects can induce shifts up to a few percent of the linewidth, assuming a pointlike detector. However, by taking into account the geometry of the setup used by the CREMA collaboration, this effect is reduced to less than 0.2% of the linewidth in all possible cases, which makes it irrelevant at the present level of accuracy., 8 pages, 4 Figs. Shorter version as recommended by the referee. More details can be found in v1

Published
2015

21. Observation of positronium annihilation in the 2S state: towards a new measurement of the 1S-2S transition frequency

Author

André Rubbia, Paolo Crivelli, V. Vrankovic, B. Brown, T. W. Haensch, S. Friedreich, D. A. Cooke, A. Gabard, Klaus Kirch, Aldo Antognini, and Janis Alnis

Subjects
Nuclear and High Energy Physics, Photon, Atomic Physics (physics.atom-ph), FOS: Physical sciences, Electron, Positronium, Bound state QED, 01 natural sciences, Physics - Atomic Physics, High Energy Physics - Experiment, High Energy Physics - Experiment (hep-ex), Positron, 0103 physical sciences, Physical and Theoretical Chemistry, 010306 general physics, Wave function, Spectroscopy, Physics, Annihilation, 010308 nuclear & particles physics, Condensed Matter Physics, Atomic and Molecular Physics, and Optics, Excited state, Atomic physics, Ground state
Abstract

We report the first observation of the annihilation of positronium from the 2S state. Positronium (Ps) is excited with a two-photon transition from the 1S to the 2S state where its lifetime is increased by a factor of eight compared to the ground state due to the decrease in the overlap of the positron electron wave-function. The yield of delayed annihilation photons detected as a function of laser frequency is used as a new method of detecting laser-excited Ps in the 2S state. This can be considered the first step towards a new high precision measurement of the 1S–2S Ps line., Hyperfine Interactions, 233 (1), ISSN:0304-3843, ISSN:0304-3834, ISSN:1572-9540, Proceedings of the International Conference on Exotic Atoms and Related Topics (EXA 2014)

Published
2015
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22. The muonic hydrogen Lamb-shift experiment

Author

Livia Ludhova, V. W. Hughes, Randolf Pohl, C.M.B. Monteiro, Françoise Mulhauser, J.F.C.A. Veloso, Satish Dhawan, Yi-Wei Liu, F. J. Hartmann, L.M.P. Fernandes, Lucile Julien, J.M.F. dos Santos, João Cardoso, Franz Kottmann, Theodor W. Hänsch, Aldo Antognini, Paul E. Knowles, David Taqqu, L. A. Schaller, Catherine Schwob, François Nez, F. D. Amaro, François Biraben, Paul Indelicato, O. Huot, A. Dax, C.A.N. Conde, and Paul Rabinowitz

Subjects
Physics, Nuclear physics, Muon, Proton, Charge radius, Excited state, General Physics and Astronomy, Radius, Atomic physics, Spectroscopy, Lamb shift, Exotic atom
Abstract

The charge radius of the proton, the simplest nucleus, is known from electron-scattering experiments only with a surprisingly low precision of about 2%. The poor knowledge of the proton charge radius restricts tests of bound-state quantum electrodynamics (QED) to the precision level of about 6 × 10–6, although the experimental data themselves (1S Lamb shift in hydrogen) have reached a precision of 2 × 10–6. The determination of the proton charge radius with an accuracy of 10–3 is the main goal of our experiment, opening a way to check bound-state QED predictions to a level of 10–7. The principle is to measure the 2S–2P energy difference in muonic hydrogen (µ–p) by infrared laser spectroscopy. The first data were taken in the second half of 2003. Muons from our unique very-low-energy muon beam are stopped at a rate of ~100 s–1 in 0.6 mbar H2 gas where the lifetime of the formed µp(2S) atoms is about 1.3 µs. An incoming muon triggers a pulsed multistage laser system that delivers ~0.2 mJ at λ ≈ 6 µm. Following the laser excitation µp(2S) → µp(2P) we observe the 1.9 keV X-rays from 2P–1S transitions using large area avalanche photodiodes. The resonance frequency, and, hence, the Lamb shift and the proton radius, is determined by measuring the intensity of these X-rays as a function of the laser wavelength. A broad range of laser frequencies was scanned in 2003 and the analysis is currently under way. PACS Nos.: 36.10.Dr, 14.20.Dh, 42.62.Fi

Published
2005

23. Lifetime and population of the 2S state in muonic hydrogen and deuterium

Author

Marc Diepold, Jan Vogelsang, Paul E. Knowles, François Nez, Catherine Schwob, C.M.B. Monteiro, Andreas Dax, K. Schuhmann, David Taqqu, João Cardoso, Livia Ludhova, Eric-Olivier Le Bigot, Lucile Julien, Franz Kottmann, Paul Rabinowitz, Theodor W. Hänsch, Randolf Pohl, François Biraben, Joaquim M. F. dos Santos, L.M.P. Fernandes, Yi-Wei Liu, J. A. M. Lopes, Thomas Graf, D. S. Covita, Paul Indelicato, J.F.C.A. Veloso, Adolf Giesen, Satish Dhawan, Tobias Nebel, F. D. Amaro, Lukas A. Schaller, Cheng-Yang Kao, F. Mulhauser, Aldo Antognini, and Andrea L. Gouvea

Subjects
Physics, education.field_of_study, Muon, 010308 nuclear & particles physics, Population, State (functional analysis), 01 natural sciences, Atomic and Molecular Physics, and Optics, Deuterium, Excited state, Metastability, 0103 physical sciences, Molecule, Atomic physics, 010306 general physics, education, muonic hydrogen, deuterium, Exotic atom
Abstract

Radiative deexcitation (RD) of the metastable 2S state of muonic protium and deuterium atoms has been observed. In muonic protium, we improve the precision on lifetime and population (formation probability) values for the short-lived {\mu}p(2S) component, and give an upper limit for RD of long-lived {\mu}p(2S) atoms. In muonic deuterium at 1 hPa, 3.1 +-0.3 % of all stopped muons form {\mu}d(2S) atoms. The short-lived 2S component has a population of 1.35 +0.57 -0.33 % and a lifetime of {\tau}_short({\mu}d) = 138 +32 -34 ns. We see evidence for RD of long-lived {\mu}d(2S) with a lifetime of {\tau}_long({\mu}d) = 1.15 +0.75 -0.53 {\mu}s. This is interpreted as formation and decay of excited muonic molecules.

Published
2013

24. Proton Structure from the Measurement of 2S-2P Transition Frequencies of Muonic Hydrogen

Author

Marc Diepold, J.F.C.A. Veloso, Jan Vogelsang, Françoise Mulhauser, Franz Kottmann, D. S. Covita, Satish Dhawan, C.M.B. Monteiro, Andreas Dax, Theodor W. Hänsch, Livia Ludhova, J. A. M. Lopes, Lukas A. Schaller, Yi-Wei Liu, David Taqqu, François Nez, Paul Rabinowitz, Eric-Olivier Le Bigot, Andrea L. Gouvea, João Cardoso, Tobias Nebel, Cheng-Yang Kao, F. D. Amaro, Karsten Schuhmann, Lucile Julien, Paul E. Knowles, Adolf Giesen, Catherine Schwob, Joaquim M. F. dos Santos, Paul Indelicato, Thomas Graf, L.M.P. Fernandes, Randolf Pohl, Aldo Antognini, and François Biraben

Subjects
Femtometer, Multidisciplinary, Muon, Proton, 010308 nuclear & particles physics, Chemistry, Radius, 01 natural sciences, Muonic Hydrogen, Nuclear physics, Proton Structure, Charge radius, 0103 physical sciences, Atomic physics, 010306 general physics, Spectroscopy, GeneralLiterature_REFERENCE(e.g.,dictionaries,encyclopedias,glossaries), Order of magnitude, Exotic atom
Abstract

Proton Still Too Small Despite a proton's tiny size, it is possible to measure its radius based on its charge or magnetization distributions. Traditional measurements of proton radius were based on the scattering between protons and electrons. Recently, a precision measurement of a line in the spectrum of muonium—an atom consisting of a proton and a muon, instead of an electron—revealed a radius inconsistent with that deduced from scattering studies. Antognini et al. (p. 417 ; see the Perspective by Margolis ) examined a different spectral line of muonium, with results less dependent on theoretical analyses, yet still inconsistent with the scattering result; in fact, the discrepancy increased.

Published
2013

25. Muonium Emission into Vacuum from Mesoporous Thin Films at Cryogenic Temperatures

Author

K. S. Khaw, Bernardo Barbiellini, K. Kwuida, Laszlo Liszkay, Paolo Crivelli, Thomas Prokscha, Zaher Salman, Klaus Kirch, Aldo Antognini, Elvezio Morenzoni, Florian M. Piegsa, and Andreas Suter

Subjects
Physics, Atomic Physics (physics.atom-ph), 010308 nuclear & particles physics, Muonium, FOS: Physical sciences, General Physics and Astronomy, 01 natural sciences, Physics - Atomic Physics, High Energy Physics - Experiment, 3. Good health, High Energy Physics - Experiment (hep-ex), 0103 physical sciences, Thin film, Atomic physics, 010306 general physics, Energy (signal processing)
Abstract

We report on Muonium (Mu) emission into vacuum following {\mu}+ implantation in mesoporous thin SiO2 films. We obtain a yield of Mu into vacuum of (38\pm4)% at 250 K temperature and (20\pm4)% at 100 K for 5 keV {\mu}+ implantation energy. From the implantation energy dependence of the Mu vacuum yield we determine the Mu diffusion constants in these films: D250KMu = (1.6 \pm 0.1) \times 10-4 cm2/s and D100KMu = (4.2\pm0.5)\times10-5 cm2/s. Describing the diffusion process as quantum mechanical tunneling from pore-to-pore, we reproduce the measured temperature dependence T^3/2 of the diffusion constant. We extract a potential barrier of (-0.3 \pm 0.1) eV which is consistent with our computed Mu work-function in SiO2 of [-0.3,-0.9] eV. The high Mu vacuum yield even at low temperatures represents an important step towards next generation Mu spectroscopy experiments., Comment: 5 pages, 5 Figures

Published
2012

26. The proton radius puzzle

Author

Paul Indelicato, J.F.C.A. Veloso, T. Graf, Satish Dhawan, Randolf Pohl, Aldo Antognini, L.M.P. Fernandes, João Cardoso, F. D. Amaro, C.M.B. Monteiro, Tobias Nebel, K. Schuhmann, Françoise Mulhauser, Lukas A. Schaller, Livia Ludhova, François Nez, Adolf Giesen, Yi-Wei Liu, E.-O. Le Bigot, Cheng-Yang Kao, Andreas Dax, Theodor W. Hänsch, Paul E. Knowles, L. Julien, F. Biraben, J. A. M. Lopes, Paul Rabinowitz, D. S. Covita, Franz Kottmann, J.M.F. dos Santos, Catherine Schwob, David Taqqu, Max-Planck-Institut für Quantenoptik (MPQ), Max-Planck-Gesellschaft, Institut f¨ur Particle Physics, Departamento de Física [Coimbra] (DFC), Universidade de Coimbra [Coimbra], Laboratoire Kastler Brossel (LKB (Jussieu)), Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Departamento de Fisica [Aveiro], Universidade de Aveiro, Physics Department, Yale University [New Haven], Dausinger & Giesen Gmbh, Dausinger & Giesen GmbH, Institut für Strahwerkzeuge (IFSW), Universität Stuttgart [Stuttgart], National Tsing Hua University [Hsinchu] (NTHU), departement de physique, Albert-Ludwigs-Universität Freiburg, Department of Chemistry, Princeton University, Paul Scherrer Institute (PSI), Université Pierre et Marie Curie - Paris 6 (UPMC)-Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), and Stuttgart University

Subjects
Physics, History, Muon, Proton, [PHYS.PHYS.PHYS-ATOM-PH]Physics [physics]/Physics [physics]/Atomic Physics [physics.atom-ph], 010308 nuclear & particles physics, Scattering, Hadron, Elementary particle, Radius, 01 natural sciences, Computer Science Applications, Education, 0103 physical sciences, Atomic physics, 010306 general physics, Nucleon, Lepton
Abstract

International audience; By means of pulsed laser spectroscopy applied to muonic hydrogen (mu(-)p) we have measured the 2S(1/2)(F=1) - 2P(3/2)(F=2) transition frequency to be 49881.88(76) GHz [1]. By comparing this measurement with its theoretical prediction [2, 3, 4, 5, 6, 7] based on bound-state QED we have determined a proton radius value of r(p) = 0.84184(67) fm. This new value differs by 5.0 standard deviations from the CODATA value of 0.8768(69) fm [8], and 3 standard deviation from the e-p scattering results of 0.897(18) fm [9]. The observed discrepancy may arise from a computational mistake of the energy levels in mu p or H, or a fundamental problem in bound-state QED, an unknown effect related to the proton or the muon, or an experimental error.

Published
2012

27. The size of the proton From the Lamb-shift in muonic hydrogen

Author

L.M.P. Fernandes, Lucile Julien, Paul Indelicato, François Nez, Randolf Pohl, Karsten Schuhmann, F. Biraben, J. A. M. Lopes, C.M.B. Monteiro, Andreas Dax, D. S. Covita, Catherine Schwob, Yi-Wei Liu, Lukas A. Schaller, Franz Kottmann, Paul E. Knowles, João Cardoso, Cheng-Yang Kao, F. D. Amaro, Thomas Graf, Livia Ludhova, E.-O. Le Bigot, J.F.C.A. Veloso, Satish Dhawan, Aldo Antognini, Tobias Nebel, J.M.F. dos Santos, David Taqqu, Paul Rabinowitz, Adolf Giesen, Françoise Mulhauser, and Theodor W. Hänsch

Subjects
0301 basic medicine, Nuclear and High Energy Physics, Muon, Proton, Chemistry, Muonic hydrogen, Hydrogen atom, Condensed Matter Physics, 01 natural sciences, Atomic and Molecular Physics, and Optics, Lamb shift, 03 medical and health sciences, Rydberg constant, 030104 developmental biology, Deuterium, Charge radius, 0103 physical sciences, Physics::Atomic Physics, Physical and Theoretical Chemistry, Atomic physics, Laser spectroscopy, 010303 astronomy & astrophysics, Proton charge radius, Bohr radius
Abstract

The root-mean-square (rms) charge radius r p of the proton has so far been known only with a surprisingly low precision of about 1% from both electron scattering and precision spectroscopy of hydrogen. We have recently determined r p by means of laser spectroscopy of the Lamb shift in the exotic “muonic hydrogen” atom. Here, the muon, which is the 200 times heavier cousin of the electron, orbits the proton with a 200 times smaller Bohr radius. This enhances the sensitivity to the proton’s finite size tremendously. Our new value r p = 0.84184 (67) fm is ten times more precise than the generally accepted CODATA-value, but it differs by 5 standard deviations from it. A lively discussion about possible solutions to the “proton size puzzle” has started. Our measurement, together with precise measurements of the 1S–2S transition in regular hydrogen and deuterium, also yields improved values of the Rydberg constant, R ∞ = 10,973,731.568160 (16) m − 1.

Published
2011

28. The size of the proton and the deuteron

Author

J.F.C.A. Veloso, Satish Dhawan, Livia Ludhova, François Nez, Lucile Julien, Catherine Schwob, Yi-Wei Liu, Randolf Pohl, Paul Indelicato, Joaquim M. F. dos Santos, João Cardoso, Franz Kottmann, D. S. Covita, L.M.P. Fernandes, David Taqqu, C.M.B. Monteiro, Andreas Dax, J. A. M. Lopes, Paul E. Knowles, F. D. Amaro, Aldo Antognini, Thomas Graf, Karsten Schuhmann, Lukas A. Schaller, Eric-Olivier Le Bigot, Tobias Nebel, Françoise Mulhauser, Cheng-Yang Kao, Paul Rabinowitz, Adolf Giesen, Theodor W. Hänsch, François Biraben, Technische Universität Dresden = Dresden University of Technology (TU Dresden), Universidade do Estado do Rio de Janeiro [Rio de Janeiro] (UERJ), Max-Planck-Institut für Quantenoptik (MPQ), Max-Planck-Gesellschaft, Université Paris 06, Faculdade de Engenharia da Universidade do Porto (FEUP), Universidade do Porto, Departamento de Fisica [Aveiro], Universidade de Aveiro, Ecole Polytechnique Fédérale de Lausanne (EPFL), Physics Department, Yale University [New Haven], Departamento de Física, University of Coimbra [Portugal] (UC), Institut für Strahwerkzeuge (IFSW), Stuttgart University, Laboratoire d'Economie et de Gestion (LEG), Université de Bourgogne (UB)-Centre National de la Recherche Scientifique (CNRS), National Tsing Hua University [Hsinchu] (NTHU), Laboratoire Kastler Brossel (LKB (Jussieu)), Université Pierre et Marie Curie - Paris 6 (UPMC)-Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Institut d'Électronique et des Technologies du numéRique (IETR), Nantes Université (NU)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Centro de Quimica Estrutural (CQE), Instituto Superior Técnico, Universidade Técnica de Lisboa (IST), Département de Physique (dpuf), Albert-Ludwigs-Universität Freiburg, Department of Chemistry, Princeton University, Institut des Nanosciences de Paris (INSP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Paul Scherrer Institute (PSI), Institut fur Teilchenphysik [Zürich], Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Technische Universität Dresden ( TUD ), Universidade do Estado do Rio de Janeiro, UERJ, Max-Planck-Institut für Quantenoptik ( MPQ ), Max-Planck-Institut, Faculdade de Engenharia [Porto] ( FEUP ), Universidade do Porto [Porto], Ecole Polytechnique Fédérale de Lausanne ( EPFL ), Université Yale - New Haven, University of Coimbra [Portugal] ( UC ), Institut für Strahwerkzeuge ( IFSW ), Laboratoire d'Economie et de Gestion ( LEG ), Université de Bourgogne ( UB ) -Centre National de la Recherche Scientifique ( CNRS ), CEMAGREF Antony, CEMAGREF, Laboratoire Kastler Brossel ( LKB (Jussieu) ), Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris ( FRDPENS ), École normale supérieure - Paris ( ENS Paris ) -Centre National de la Recherche Scientifique ( CNRS ) -École normale supérieure - Paris ( ENS Paris ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Centre National de la Recherche Scientifique ( CNRS ), Institut d'Electronique et de Télécommunications de Rennes ( IETR ), Université de Nantes ( UN ) -Université de Rennes 1 ( UR1 ), Université de Rennes ( UNIV-RENNES ) -Université de Rennes ( UNIV-RENNES ) -Institut National des Sciences Appliquées - Rennes ( INSA Rennes ) -CentraleSupélec-Centre National de la Recherche Scientifique ( CNRS ), Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Département de Physique ( dpuf ), Institut des Nanosciences de Paris ( INSP ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Centre National de la Recherche Scientifique ( CNRS ), Paul Scherrer Institute ( PSI ), Institut fur Teilchenphysik, Swiss Federal Institute of Technology in Zürich ( ETH Zürich ), Universidade do Porto = University of Porto, Universität Stuttgart [Stuttgart], Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Université de Nantes (UN)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), and Université de Nantes (UN)-Université de Rennes 1 (UR1)

Subjects
Physics, History, Proton, [PHYS.PHYS.PHYS-ATOM-PH]Physics [physics]/Physics [physics]/Atomic Physics [physics.atom-ph], [ PHYS.PHYS.PHYS-ATOM-PH ] Physics [physics]/Physics [physics]/Atomic Physics [physics.atom-ph], Hydrogen atom, 01 natural sciences, 010305 fluids & plasmas, Computer Science Applications, Education, Nuclear physics, Rydberg constant, Deuterium, Charge radius, 0103 physical sciences, Atom, Physics::Atomic Physics, Atomic physics, 010306 general physics, Hyperfine structure, Exotic atom
Abstract

We have recently measured the 2S1/2⁼¹ − 2P3/2 ⁼ ² energy splitting in the muonic hydrogen atom μp to be 49881.88 (76) GHz. Using recent QED calculations of the fine-, hyperfine, QED and finite size contributions we obtain a root-mean-square proton charge radius of rp = 0.84184 (67) fm. This value is ten times more precise, but 5 standard deviations smaller, than the 2006 CODATA value of rp = 0.8768 (69) fm. The source of this discrepancy is unknown. Using the precise measurements of the 1S-2S transition in regular hydrogen and deuterium and our value of rp we obtain improved values of the Rydberg constant, R∞ = 10973731.568160 (16) m⁻¹and the rms charge radius of the deuteron rd = 2.12809 (31) fm.

Published
2011

29. Muonic hydrogen spectroscopy: the proton radius puzzle

Author

Randolf Pohl, Adolf Giesen, Lukas A. Schaller, Lucile Julien, João Cardoso, Tobias Nebel, Cheng-Yang Kao, Joaquim M. F. dos Santos, Paul E. Knowles, Françoise Mulhauser, Paul Indelicato, L.M.P. Fernandes, Paul Rabinowitz, Livia Ludhova, J. A. M. Lopes, F. D. Amaro, C.M.B. Monteiro, Andreas Dax, D. S. Covita, David Taqqu, François Nez, Theodor W. Hänsch, François Biraben, Yi-Wei Liu, Eric-Olivier Le Bigot, Aldo Antognini, Franz Kottmann, Thomas Graf, Karsten Schuhmann, Catherine Schwob, J.F.C.A. Veloso, Satish Dhawan, Max-Planck-Institut für Quantenoptik (MPQ), Max-Planck-Gesellschaft, Laboratoire Kastler Brossel (LKB (Jussieu)), Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Departamento de Física [Coimbra] (DFC), Universidade de Coimbra [Coimbra], Departamento de Fisica [Aveiro], Universidade de Aveiro, Physics Department, Yale University [New Haven], Technol Gesell Strahlwerkzeuge, Universität Stuttgart [Stuttgart], Institut für Strahwerkzeuge (IFSW), National Tsing Hua University [Hsinchu] (NTHU), departement de physique, Albert-Ludwigs-Universität Freiburg, Institut f¨ur Particle Physics, Department of Chemistry, Princeton University, Paul Scherrer Institute (PSI), Université Pierre et Marie Curie - Paris 6 (UPMC)-Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), and Stuttgart University

Subjects
Physics, Muon, Proton, Hydrogen, chemistry, [PHYS.PHYS.PHYS-ATOM-PH]Physics [physics]/Physics [physics]/Atomic Physics [physics.atom-ph], Scattering, chemistry.chemical_element, Radius, Atomic physics, Spectroscopy, Standard deviation, Exotic atom
Abstract

International audience; By means of pulsed laser spectroscopy applied to muonic hydrogen (mu(-)p) we have measured the 2S(1/2)(F=1) - 2P(3/2)(F=2) transition frequency to be 49881.88(76) GHz.(1) By comparing this measurement with its theoretical prediction (2-7) based on bound-state QED we have determined a proton radius value of r(p) = 0.84184(67) fm. This new value differs by 5.0 standard deviations from the CODATA value of 0.8768(69) fm,(8) and 3 standard deviation from the e-p scattering results of 0.897(18) fm.(9) The observed discrepancy may arise from a computational mistake of the energy levels in mu p or H, or a fundamental problem in bound-state QED, an unknown effect related to the proton or the muon, or an experimental error.

Published
2010

30. The size of the proton

Author

Eric-Olivier Le Bigot, J.F.C.A. Veloso, Satish Dhawan, Livia Ludhova, F. D. Amaro, C.M.B. Monteiro, Andreas Dax, Randolf Pohl, Tobias Nebel, Yi-Wei Liu, François Nez, Theodor W. Hänsch, Aldo Antognini, Lukas A. Schaller, Lucile Julien, L.M.P. Fernandes, João Cardoso, Paul E. Knowles, Franz Kottmann, Joaquim M. F. dos Santos, D. S. Covita, F. Biraben, Karsten Schuhmann, J. A. M. Lopes, Paul Rabinowitz, Catherine Schwob, Cheng-Yang Kao, Adolf Giesen, Françoise Mulhauser, Paul Indelicato, David Taqqu, Thomas Graf, Max-Planck-Institut für Quantenoptik (MPQ), Max-Planck-Gesellschaft, Laboratoire Kastler Brossel (LKB (Jussieu)), Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Departamento de Física, University of Coimbra [Portugal] (UC), Physics Department, Yale University [New Haven], Technol Gesell Strahlwerkzeuge, Universität Stuttgart [Stuttgart], Institut für Strahwerkzeuge (IFSW), Sektion Physik, Ludwig-Maximilians-Universität München (LMU), National Tsing Hua University [Hsinchu] (NTHU), Département de Physique (dpuf), Albert-Ludwigs-Universität Freiburg, Departamento de Física [Coimbra] (DFC), Universidade de Coimbra [Coimbra], departement de physique, Department of Chemistry, Princeton University, Paul Scherrer Institute (PSI), Université Pierre et Marie Curie - Paris 6 (UPMC)-Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), and Stuttgart University

Subjects
Physics, Multidisciplinary, Muon, proton radius, Proton, Anomalous magnetic dipole moment, [PHYS.PHYS.PHYS-ATOM-PH]Physics [physics]/Physics [physics]/Atomic Physics [physics.atom-ph], 010308 nuclear & particles physics, Electron, 01 natural sciences, 7. Clean energy, Lamb shift, Rydberg constant, Charge radius, 0103 physical sciences, Physics::Atomic Physics, Atomic physics, 010306 general physics, proton size, muonic hydrogen, Bohr radius, ComputingMilieux_MISCELLANEOUS
Abstract

Considering that the proton is a basic subatomic component of all ordinary matter — as well as being ubiquitous in its solo role as the hydrogen ion H+ — there are some surprising gaps in our knowledge of its structure and behaviour. A collaborative project to determine the root-mean-square charge radius of the proton to better than the 1% accuracy of the current 'best' value suggests that those knowledge gaps may be greater than was thought. The new determination comes from a technically challenging spectroscopic experiment — the measurement of the Lamb shift (the energy difference between a specific pair of energy states) in 'muonic hydrogen', an exotic atom in which the electron is replaced by its heavier twin, the muon. The result is unexpected: a charge radius about 4% smaller than the previous value. The discrepancy remains unexplained. Possible implications are that the value of the most accurately determined fundamental constant, the Rydberg constant, will need to be revised — or that the validity of quantum electrodynamics theory is called into question. Here, a technically challenging spectroscopic experiment is described: the measurement of the muonic Lamb shift. The results lead to a new determination of the charge radius of the proton. The new value is 5.0 standard deviations smaller than the previous world average, a large discrepancy that remains unexplained. Possible implications of the new finding are that the value of the Rydberg constant will need to be revised, or that the validity of quantum electrodynamics theory is called into question. The proton is the primary building block of the visible Universe, but many of its properties—such as its charge radius and its anomalous magnetic moment—are not well understood. The root-mean-square charge radius, rp, has been determined with an accuracy of 2 per cent (at best) by electron–proton scattering experiments1,2. The present most accurate value of rp (with an uncertainty of 1 per cent) is given by the CODATA compilation of physical constants3. This value is based mainly on precision spectroscopy of atomic hydrogen4,5,6,7 and calculations of bound-state quantum electrodynamics (QED; refs 8, 9). The accuracy of rp as deduced from electron–proton scattering limits the testing of bound-state QED in atomic hydrogen as well as the determination of the Rydberg constant (currently the most accurately measured fundamental physical constant3). An attractive means to improve the accuracy in the measurement of rp is provided by muonic hydrogen (a proton orbited by a negative muon); its much smaller Bohr radius compared to ordinary atomic hydrogen causes enhancement of effects related to the finite size of the proton. In particular, the Lamb shift10 (the energy difference between the 2S1/2 and 2P1/2 states) is affected by as much as 2 per cent. Here we use pulsed laser spectroscopy to measure a muonic Lamb shift of 49,881.88(76) GHz. On the basis of present calculations11,12,13,14,15 of fine and hyperfine splittings and QED terms, we find rp = 0.84184(67) fm, which differs by 5.0 standard deviations from the CODATA value3 of 0.8768(69) fm. Our result implies that either the Rydberg constant has to be shifted by −110 kHz/c (4.9 standard deviations), or the calculations of the QED effects in atomic hydrogen or muonic hydrogen atoms are insufficient.

Published
2010

31. Muonic hydrogen cascade time and lifetime of the short-lived $2S$ state

Author

C.M.B. Monteiro, Aldo Antognini, David Taqqu, Lukas A. Schaller, J. A. M. Lopes, Yi-Wei Liu, J.F.C.A. Veloso, L.M.P. Fernandes, Satish Dhawan, Françoise Mulhauser, João Cardoso, Lucile Julien, V. W. Hughes, Andreas Dax, Paul E. Knowles, Paul Rabinowitz, Livia Ludhova, Theodor W. Hänsch, F. D. Amaro, François Biraben, Randolf Pohl, J.M.F. dos Santos, Paul Indelicato, François Nez, Catherine Schwob, Franz Kottmann, C.A.N. Conde, Paul Scherrer Institute (PSI), Département de Physique (dpuf), Albert-Ludwigs-Universität Freiburg, Departamento de Física, University of Coimbra [Portugal] (UC), Max-Planck-Institut für Quantenoptik (MPQ), Max-Planck-Gesellschaft, Laboratoire Kastler Brossel (LKB (Jussieu)), Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Physics Department, Yale University [New Haven], Institut für Teilchenphysik, Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), National Tsing Hua University [Hsinchu] (NTHU), Department of Chemistry, Princeton University, Université Pierre et Marie Curie - Paris 6 (UPMC)-Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, education.field_of_study, [PHYS.PHYS.PHYS-ATOM-PH]Physics [physics]/Physics [physics]/Atomic Physics [physics.atom-ph], Atomic Physics (physics.atom-ph), 010308 nuclear & particles physics, muonic atoms, Population, FOS: Physical sciences, State (functional analysis), Kinetic energy, 01 natural sciences, 7. Clean energy, Atomic and Molecular Physics, and Optics, Physics - Atomic Physics, Gas pressure, 0103 physical sciences, Atom, metastable states, Physics::Atomic Physics, Atomic physics, 36.10.Dr, 34.50.Fa, 010306 general physics, education, Energy (signal processing), Exotic atom
Abstract

Metastable ${2S}$ muonic-hydrogen atoms undergo collisional ${2S}$-quenching, with rates which depend strongly on whether the $\mu p$ kinetic energy is above or below the ${2S}\to {2P}$ energy threshold. Above threshold, collisional ${2S} \to {2P}$ excitation followed by fast radiative ${2P} \to {1S}$ deexcitation is allowed. The corresponding short-lived $\mu p ({2S})$ component was measured at 0.6 hPa $\mathrm{H}_2$ room temperature gas pressure, with lifetime $\tau_{2S}^\mathrm{short} = 165 ^{+38}_{-29}$ ns (i.e., $\lambda_{2S}^\mathrm{quench} = 7.9 ^{+1.8}_{-1.6} \times 10^{12} \mathrm{s}^{-1}$ at liquid-hydrogen density) and population $\epsilon_{2S}^\mathrm{short} = 1.70^{+0.80}_{-0.56}$ % (per $\mu p$ atom). In addition, a value of the $\mu p$ cascade time, $T_\mathrm{cas}^{\mu p} = (37\pm5)$ ns, was found., Comment: 4 pages, 3 figures

Published
2006

32. The 2S Lamb shift in muonic hydrogen and the proton rms charge radius

Author

F. Mulhauser, Paul Rabinowitz, J.A.M. Lopes, C.M.B. Monteiro, Randolf Pohl, João Cardoso, F. Kottmann, Catherine Schwob, Andreas Dax, Adolf Giesen, F. D. Amaro, Theodor W. Hänsch, L.M.P. Fernandes, François Biraben, D. Taqqu, U. Brauch, F. Nez, Yi-Wei Liu, Paul Indelicato, Aldo Antognini, Paul E. Knowles, C.A.N. Conde, Lukas A. Schaller, L. Julien, J.F.C.A. Veloso, Satish Dhawan, J.M.F. dos Santos, Livia Ludhova, and C. Stolzenburg

Subjects
Physics, Muon, Proton, Hydrogen, Far-infrared laser, chemistry.chemical_element, Laser, law.invention, Lamb shift, chemistry, Charge radius, law, Physics::Atomic Physics, Atomic physics, Spectroscopy
Abstract

The determination of the proton rms charge radius with an accuracy of 10−3 is the main goal of our experiment, opening the way to check bound‐state QED predictions in hydrogen to a level of 10−7. The principle is to measure the 2S1/2(F = 1) − 2P3/2(F = 2) energy difference in muonic hydrogen (μ−p) by infrared laser spectroscopy to a precision of 30 ppm. Very low‐energy negative muons are stopped in 0.6 mbar of hydrogen gas, where, following the μ− atomic capture and cascade, 1% of the muonic hydrogen atoms form the metastable 2S state with a lifetime of 1.3 μs. A 6 μm laser pulse is used to drive the 2S → 2P transition. When on resonance, the laser induces the transition, and the subsequent muonic deexcitation to the 1S state emits a 1.9 keV x ray which is detected by avalanche photodiodes. The resonance frequency, and hence the Lamb shift and the proton charge radius, is determined by measuring the rate of laser‐induced x rays as a function of the laser wavelength. Some details of the experiment, recent measurements and improvements will be presented.

Published
2005

33. Large area APDs for low energy X-ray detection in intense magnetic fields

Author

Livia Ludhova, M. Boucher, David Taqqu, C.A.N. Conde, L.M.P. Fernandes, Franz Kottmann, Françoise Mulhauser, Paul E. Knowles, O. Huot, Randolf Pohl, Lukas A. Schaller, J.F.C.A. Veloso, Aldo Antognini, and J.M.F. dos Santos

Subjects
Physics, Nuclear and High Energy Physics, X-ray detection, Muon, Photon, Hydrogen, business.industry, Avalanche photodiodes, chemistry.chemical_element, Photon detectors, Laser, Avalanche photodiode, Lamb shift, Magnetic field, law.invention, Optics, chemistry, law, Physics::Atomic Physics, Atomic physics, business, Instrumentation, Tunable laser
Abstract

An experiment to measure the energy difference between the 2S-2P atomic levels (Lamb shift) in muonic hydrogen is being prepared at PSI. Since the energy levels of muonic hydrogen are a factor of 186 more energetic than those of hydrogen, according to the ratio of reduced masses, the transitions lie in the soft X-ray region. The experiment needs long-lived muonic hydrogen in the 2S state. This is achieved by stopping a low energy muon beam in a small volume of low pressure hydrogen in a 5 T magnetic field. A pulsed beam from a tunable laser induces the 2S-2P transition and the 1.9 keV X-ray photons resulting from the 2P-1S deexcitation will be detected. Measuring the coincidences between the laser pulse and the X-ray as a function of the laser wavelength allows us to determine the Lamb shift. In this presentation we will discuss the perspectives of using large area avalanche photodiodes for the direct detection of the X-rays. Compared to gaseous detectors, they are more compact and simpler in operation. They are also insensitive to magnetic fields. http://www.sciencedirect.com/science/article/B6TJM-4871204-X/1/e33bbbdca623e18bf326aab66966ba9f

Published
2003

34. Application of large-area avalanche photodiodes to X-ray spectrometry of muonic atoms

Author

Randolf Pohl, Franz Kottmann, C.A.N. Conde, F. Mulhauser, Lukas A. Schaller, Livia Ludhova, J.F.C.A. Veloso, M. Boucher, L.M.P. Fernandes, O. Huot, J.M.F. dos Santos, David Taqqu, Paul E. Knowles, and Aldo Antognini

Subjects
Physics, Muon, Physics::Instrumentation and Detectors, Avalanche photodiodes, Astrophysics::High Energy Astrophysical Phenomena, Electron, Radiation, Avalanche photodiode, Signal, Atomic and Molecular Physics, and Optics, Spectral line, Analytical Chemistry, Lamb shift, Nuclear physics, Muonic atoms X-ray spectrometry, Physics::Atomic Physics, Atomic physics, Instrumentation, Spectroscopy, Exotic atom
Abstract

Large-area avalanche photodiodes have been investigated as 1.9-keV X-ray detectors for the muonic hydrogen Lamb-shift experiment. We report experimental tests carried out for evaluation of the avalanche photodiode capabilities for X-ray detection in the intense radiation and low counting rate environment of experiments with muonic atoms. Several muonic atoms were used and it was shown that the electronic background of muonic atom X-ray spectra can be reduced simply by timing the X-ray signal against the gate signal produced by the muon entrance. Furthermore, the background can be eliminated using coincidences between the X-ray signal and the signal resulting from the electron due to the muon decay. This coincidence discrimination results, however, in a reduction of the X-ray detection efficiency. http://www.sciencedirect.com/science/article/B6THN-4B6608X-11/1/4bb8c2b08d267e2eba00e1ae64b143a9

Published
2003

35. The Lamb shift in muonic hydrogen and the proton radius

Author

Catherine Schwob, David Taqqu, Paul Indelicato, A. Voss, J.F.C.A. Veloso, Klaus Kirch, Satish Dhawan, Livia Ludhova, J.M.F. dos Santos, Tobias Nebel, Franz Kottmann, Paul E. Knowles, F. D. Amaro, Aldo Antognini, J. A. M. Lopes, Yi-Wei Liu, C.M.B. Monteiro, Andreas Dax, D. S. Covita, François Nez, Th. Graf, L.M.P. Fernandes, K. Schuhmann, Lukas A. Schaller, L. Julien, François Biraben, Françoise Mulhauser, T.W. Ḧansch, João Cardoso, Cheng-Yang Kao, Randolf Pohl, Malte Hildebrandt, E.-O. Le Bigot, Andrea L. Gouvea, Adolf Giesen, Paul Rabinowitz, Max-Planck-Institut für Quantenoptik (MPQ), Max-Planck-Gesellschaft, Institut fur Teilchenphysik [Zürich], Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Departamento de Física [Coimbra] (DFC), Universidade de Coimbra [Coimbra], Laboratoire Kastler Brossel (LKB (Jussieu)), Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Physics Department, Yale University [New Haven], Technol Gesell Strahlwerkzeuge, Universität Stuttgart [Stuttgart], Institut für Strahwerkzeuge (IFSW), Paul Scherrer Institute (PSI), National Tsing Hua University [Hsinchu] (NTHU), departement de physique, Albert-Ludwigs-Universität Freiburg, Department of Chemistry, Princeton University, Dausinger & Giesen GmbH, Université Pierre et Marie Curie - Paris 6 (UPMC)-Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), and Stuttgart University

Subjects
Physics, Muon, proton radius, Proton, [PHYS.PHYS.PHYS-ATOM-PH]Physics [physics]/Physics [physics]/Atomic Physics [physics.atom-ph], 010308 nuclear & particles physics, Radius, Physics and Astronomy(all), bound-state QED, 01 natural sciences, hydrogen-like, Lamb shift, Nuclear physics, Deuterium, Charge radius, muon, 0103 physical sciences, Atomic physics, few-nucleon, 010306 general physics, Spectroscopy, Exotic atom
Abstract

International audience; By means of pulsed laser spectroscopy applied to muonic hydrogen (mu(-) p) we have measured the 2S(1/2)(F=1) - 2P(3/2)(F=2) transition frequency to be 49881.88(76) GHz. By comparing this measurement with its theoretical prediction based on bound-state QED we have determined a proton radius value of r(p) = 0.84184 (67) fm. This new value is an order of magnitude preciser than previous results but disagrees by 5 standard deviations from the CODATA and the electron-proton scattering values. An overview of the present effort attempting to solve the observed discrepancy is given. Using the measured isotope shift of the 1S-2S transition in regular hydrogen and deuterium also the rms charge radius of the deuteron r(d) = 2.12809 (31) fm has been determined. Moreover we present here the motivations for the measurements of the mu(4)He(+) and mu(3)He(+) 2S-2P splittings. The alpha and triton charge radii are extracted from these measurements with relative accuracies of few 10(-4). Measurements could help to solve the observed discrepancy, lead to the best test of hydrogen-like energy levels and provide crucial tests for few-nucleon ab-initio theories and potentials.

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