Two-photon laser spectroscopy of antiprotonic helium atoms, and the antiproton-to-electron mass ratio

21st International Conference on Laser Spectroscopy

Hori, Masaki^1

Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Strasse 1, 85748 Garching, Germany^1

关键词: Antiprotonic helium;    Antiprotonic helium atoms;    Counterpropagating laser beams;    Electron mass;    Narrow spectral lines;    QED calculation;    Transition frequencies;    Two-photon transitions;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/467/1/012006/pdf
DOI  :  10.1088/1742-6596/467/1/012006

来源: IOP

【 摘 要 】

Some two-photon transitions in antiprotonic helium atoms at the deep UV wavelengths λ 139.8-197.0 nm were recently studied by laser spectroscopy. The thermal Doppler broadening of the observed antiprotonic resonances were reduced by exciting the atoms with two counterpropagating laser beams of wavelengths λ 265-417 nm. The resulting narrow spectral lines allowed the measurement of three transition frequencies in antiprotonic helium-3 and helium-4 isotopes with fractional precisions of 2.3-5 parts in 109. By comparing the results with three-body QED calculations, the antiproton-to-electron mass ratio was derived as 1836.1526736(23). We briefly review these experimental results that were presented in Ref. [1].