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