Abstract
The ASACUSA collaboration of CERN has carried out two-photon laser spectroscopy of antiprotonic helium atoms using counter-propagating ultraviolet laser beams. This excited some non-linear transitions of the antiproton at the wavelengths λ = 139.8–197.0 nm, in a way that reduced the thermal Doppler broadening of the observed resonances. The resulting narrow spectral lines allowed the measurement of three transition frequencies with fractional precisions of 2.3–5 parts in 109. By comparing these values with three-body QED calculations, the antiproton-to-electron mass ratio was derived as 1836.1526736(23). We briefly review these results.
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Proceedings of the 9th International Workshop on Application of Lasers and Storage Devices in Atomic Nuclei Research “Recent Achievements and Future Prospects” (LASER 2013) held in Poznan, Poland, 13-16 May, 2013
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Hori, M. Two photon laser spectroscopy of antiprotonic helium atoms at CERN’s AD. Hyperfine Interact 227, 17–22 (2014). https://doi.org/10.1007/s10751-014-1022-y
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DOI: https://doi.org/10.1007/s10751-014-1022-y