Collision-induced radiative quenching and other disintegration modes of the $2S$ state of muonic hydrogen and deuterium atoms

Abstract

The formation and various disintegration modes of (µ − p)2s and (µ − d)2s at kinetic energies both above and below the 2s − 2p threshold are studied. Fully quantum-mechanical calculations of the differential and integrated cross sections of the radiative collisional quenching, elastic scattering and Coulomb deexcitation of (µ − p)2s and (µ − d)2s atoms in collisions with ordinary hydrogen and deuterium atoms have been calculated at collision energies below the 2s−2p inelastic excitation. All scattering processes are treated in a unified manner in a framework of the close-coupling approach. The basis set includes all open and closed channels corresponding to exotic-atom states with principal quantum numbers from n = 1 up to nmax = 30. The kinetics of atomic cascade for µ − p and µ − d atoms was studied in the wide range of the relative target densities, φ = 10 −8 − 1 applying the improved version of the extended cascade model. Results of the numerical quantum-mechanical calculations of cross sections for principal quantum numbers n and kinetic energies of muonic atoms that are of interest for detailed cascade calculations were used as input data. The initial population, absolute yields and decay probabilities of the different disintegration modes as well as lifetime of the 2s state for both muonic hydrogen and deuterium atoms are calculated at kinetic energies above and below the 2s − 2p threshold. The theoretical results are compared with the known experimental data.