Nuclear structure corrections to the Lamb shift in μHe+3 and μH3
N. Nevo Dinur (Racah Institute of Physics, The Hebrew University, Jerusalem, 9190401, Israel)
; C. Ji (TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T 2A3, Canada, ECT*, Villa Tambosi, Villazzano (Trento), 38123, Italy, INFN-TIFPA, Trento Institute for Fundamental Physics and Applications, Trento, Italy); S. Bacca (TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T 2A3, Canada, Department of Physics and Astronomy, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada); N. Barnea (Racah Institute of Physics, The Hebrew University, Jerusalem, 9190401, Israel)
Measuring the 2S–2P Lamb shift in a hydrogen-like muonic atom allows one to extract its nuclear charge radius with a high precision that is limited by the uncertainty in the nuclear structure corrections. The charge radius of the proton thus extracted was found to be 7 σ away from the CODATA value, in what has become the yet unsolved “proton radius puzzle”. Further experiments currently aim at the isotopes of hydrogen and helium: the precise extraction of their radii may provide a hint at the solution of the puzzle. We present the first ab initio calculation of nuclear structure corrections, including the nuclear polarization correction, to the 2S–2P transition in μHe+3 and μH3 , and assess solid theoretical error bars. Our predictions reduce the uncertainty in the nuclear structure corrections to the level of a few percent and will be instrumental to the on-going μHe+3 experiment. We also support the mirror μH3 system as a candidate for further probing of the nucleon polarizabilities and shedding more light on the puzzle.
