The $μ^-d$ capture rate in effective field theory

S. Ando, T. -S. Park, K. Kubodera, F. Myhrer

Published 2001-09-18Version 1

Muon capture on the deuteron is studied in heavy baryon chiral perturbation theory (HBChPT). It is found that by far the dominant contribution to $\mu d$ capture comes from a region of the final three-body phase-space in which the energy of the two neutrons is sufficiently small for HBChPT to be applicable. The single unknown low-energy constant having been fixed from the tritium beta decay rate, our calculation contains no free parameter. Our estimate of the $\mu d$ capture rate is consistent with the existing data. The relation between $\mu d$ capture and the $\nu d$ reactions, which are important for the SNO experiments, is briefly discussed.