Journal article

Status of the muonic hydrogen Lamb-shift experiment

  • Nebel, T. Max-Planck-Institutfur Quantenoptik, Garching, Germany
  • Amaro, F. D. Departamento de Fisica, Universidade de Coimbra, Portugal
  • Antognini, A. Max-Planck-Institutfur Quantenoptik, Garching, Germany
  • Biraben, F. Laboratoire Kastler Brossel, ENS, UPMC, CNRS, Paris, France
  • Cardoso, J. M. R. Departamento de Fisica, Universidade de Coimbra, Portugal
  • Conde, C. A. N. Departamento de Fisica, Universidade de Coimbra, Portugal
  • Dax, A. Physics Department, Yale University,New Haven, USA
  • Dhawan, S. Physics Department, Yale University,New Haven, USA
  • Fernandes, L. M. P. Departamento de Fisica, Universidade de Coimbra, Portugal
  • Giesen, A. Institut fur Strahlwerkzeuge, Stuttgart, Germany
  • Hänsch, T. W. Max-Planck-Institutfur Quantenoptik, Garching, Germany
  • Indelicato, P. Laboratoire Kastler Brossel, ENS, UPMC, CNRS, Paris, France
  • Julien, L. Laboratoire Kastler Brossel, ENS, UPMC, CNRS, Paris, France
  • Knowles, Paul E. Département de Physique, Université de Fribourg, Switzerland
  • Kottmann, F. Institut fur Teilchenphysik, ETH Zurich, Switzerland
  • Le Bigot, E. Laboratoire Kastler Brossel, ENS, UPMC, CNRS, Paris, France
  • Liu, Y.-W. Physics Department, National Tsing Hua University, Hsinchu, Taiwan
  • Lopes, J. A. M. Departamento de Fisica, Universidade de Coimbra, Portugal
  • Ludhova, Livia Département de Physique, Université de Fribourg, Switzerland
  • Monteiro, C. M. B. Departamento de Fisica, Universidade de Coimbra, Portugal
  • Mulhauser, Françoise Département de Physique, Université de Fribourg, Switzerland
  • Nez, F. Laboratoire Kastler Brossel, ENS, UPMC, CNRS, Paris, France
  • Pohl, R. Max-Planck-Institutfur Quantenoptik, Garching, Germany
  • Rabinowitz, P. Department of Chemistry, Princeton University, Princeton, USA
  • Santos, J. M. F. dos Departamento de Fisica, Universidade de Coimbra, Portugal
  • Schaller, Lukas A. Département de Physique, Université de Fribourg, Switzerland
  • Schuhmann, K. Institut fur Strahlwerkzeuge, Stuttgart, Germany
  • Schwob, C. Laboratoire Kastler Brossel, ENS, UPMC, CNRS, Paris, France
  • Taqqu, D. Paul Scherrer Institute, Villigen-PSI, Switzerland
  • Veloso, J. F. C. A. Departamento de Fisica, Universidade de Coimbra, Portugal
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    14.05.2007
Published in:
  • Canadian Journal of Physics. - 2007, vol. 85, no. 5, p. 469-478
English The Lamb-shift experiment in muonic hydrogen (μ⁻ p) aims to measure the energy difference between the 2SF=11/2-2PF=23/2 atomic levels to a precision of 30 ppm. This would allow the r.m.s. proton charge radius rp to be deduced to a precision of 10⁻³ and open a way to check bound-state quantum electrodynamics (QED) to a level of 10⁻⁷. The poor knowledge of the proton charge radius restricts tests of bound-state QED to the precision level of about 6 × 10⁻⁶, although the experimental data themselves (Lamb-shift in hydrogen) have reached a precision of × 10⁻⁶. Values for rp not depending on bound-state QED results from electron scattering experiments have a surprisingly large uncertainty of 2%. In our Lamb-shift experiment, low-energy negative muons are stopped in low-density 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 about 1 μs. A laser pulse at λ ≈ 6 μm is used to drive the 2S → 2P transition. Following the laser excitation, we observe the 1.9 keV X-ray being emitted during the subsequent de-excitation to the 1S state using large-area avalanche photodiodes. The resonance frequency and, hence, the Lamb shift and the proton charge radius are determined by measuring the intensity of the X-ray fluorescence as a function of the laser wavelength. The results of the run in December 2003 were negative but, nevertheless, promising. One by-product of the 2003 run was the first observation of the short-lived 2S component in muonic hydrogen. Currently, improvements in the laser-system, the experimental apparatus, and the data acquisition are being implemented.
Faculty
Faculté des sciences
Department
Physique
Language
  • English
Classification
Physics
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https://folia.unifr.ch/unifr/documents/300658
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