Quasi-molecular resonances in muonic charge-exchange reactions

Abstract:

We present the first thorough theoretical discussion of non-monotonic structure in the temporal behavior of X-ray fluorescence intensity spectra of muon charge-exchange reactions of the type pμ + Z→p + μZ. Our discussion is based on semiclassical methods; our results are almost entirely analytical. We find that the reported experimental maxima of muon charge-exchange rates are very close to the theoretical limits. We identify a new quantum mechanism, quantum impedance matching, which explains observed inelastic transitions close to the Unitarity Limit. We investigate the specific example of the reaction pμO ^{8 +} in detail using two-center Coulomb adiabatic potential terms. We find that quantum impedance matched higher-order partial-wave resonances yielding muon-transfer rates close to the Unitarity Limit are responsible for the remarkable non-monotonic structure in the X-ray fluorescence spectra.