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Metastable antiprotonic helium is a neutral three-body atom [1-6] that contains a helium nucleus, an electron occupying the 1s state, and an antiproton in a Rydberg state of large principal (n≈38) and orbital angular momentum (l=n-1) quantum numbers. Whereas spectroscopy of antihydrogen atoms probes the interaction between an antihadron and antilepton, the antiprotonic helium atom is a hadron-antihadron quantum bound system having the longest known lifetime that can be readily produced. The ASACUSA collaboration at CERN will utilize the unprecedented high-quality beam of the ELENA facility and the latest laser metrology techniques to carry out sub-Doppler two-photon laser spectroscopy of narrow resonances of antiprotonic helium atoms. By comparing the results with three-body QED calculations the antiproton-to-electron mass ratio and upper limits on exotic forces that can arise between the constituent particles will be precisely determined.
[1]: V.I. Korobov, L. Hilico, J.-P. Karr, Phys. Rev. A, 032511 (2014).
[2]: A. Sótér, H. Aghai-Khozani, D. Barna, A. Dax, L. Venturelli, M. Hori, Nature 603, 411 (2022).
[3]: V.I. Korobov, L. Hilico, J.-P. Karr, Phys. Rev. A, 032511 (2014).
[4]: M. Hori et al., Science 354, 610 (2016).
[5]: M. Hori et al., Nature 475, 484 (2011).
[6]: M. Hori, H. Aghai-Khozani, A. Sótér, A. Dax, D. Barna, Nature 581, 37 (2020).
