Nature(London) 589, 527 (2021)

J.J.Krauth, K.Schuhmann, M.A.Ahmed, F.D.Amaro, P.Amaro, F.Biraben, T.-L.Chen, D.S.Covita, A.J.Dax, M.Diepold, L.M.P.Fernandes, B.Franke, S.Galtier, A.L.Gouvea, J.Gotzfried, T.Graf, T.W.Hansch, J.Hartmann, M.Hildebrandt, P.Indelicato, L.Julien, K.Kirch, A.Knecht, Y.-W.Liu, J.Machado, C.M.B.Monteiro, F.Mulhauser, B.Naar, T.Nebel, F.Nez, J.M.F.dos Santos, J.P.Santos, C.I.Szabo, D.Taqqu, J.F.C.A.Veloso, J.Vogelsang, A.Voss, B.Weichelt, R.Pohl, A.Antognini, F.Kottmann

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

ATOMIC PHYSICS ⁴He; measured frequencies; deduced resonances, isotope shifts, 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. Comparison with available data.

doi: 10.1038/s41586-021-03183-1