Reaction processes of muon-catalyzed fusion in the muonic molecule studied with the tractable -matrix model
Phys. Rev. C 113, 034603 – Published 5 March, 2026
DOI: https://doi.org/10.1103/3ddg-3p73
Abstract
Muon-catalyzed fusion has recently regained significant attention due to experimental and theoretical developments. The present authors proposed Q. Wu and M. Kamimura, [Phys. Rev. C 109, 054625 (2024)] the tractable -matrix model based on the Lippmann-Schwinger equation to approximate the elaborate two- and three-body coupled-channel (CC) calculations M. Kamimura, Y. Kino, and T. Yamashita, [Phys. Rev. C 107, 034607 (2023)] for the nuclear reaction processes in the muonic molecule . The -matrix model well reproduced almost all of the results generated by the CC work. In the present paper, we apply this model to the nuclear reaction processes in the molecule, MeV or MeV, in which the fusion takes place via the -wave relative motion. Recently, significantly different -wave astrophysical factors of the reaction or at keV to 1 MeV have been reported experimentally and theoretically by five groups. Employing many sets of nuclear interactions that can reproduce those five cases of -wave factors, we calculate the fusion rate of the molecule using three kinds of methods where results are consistent with each other. We also derive the sticking probability and the absolute values of the energy and momentum spectra of the emitted muon. The violation of charge symmetry in the -wave reaction and the fusion reaction is discussed. Information on the emitted 2.45 MeV neutrons and 1 keV dominant muons should be useful for the application of fusion.