Chiral Effective Field Theory Predictions for Muon Capture on Deuteron and 3He

The muon-capture reactions H-2(mu(-), nu(mu))nn and He-3(mu(-), nu(mu))H-3 are studied with nuclear potentials and charge-changing weak currents, derived in chiral effective field theory. The low-energy constants (LECs) c(D) and c(E), present in the three-nucleon potential and (c(D)) axial-vector current, are constrained to reproduce the A = 3 binding energies and the triton Gamow-Teller matrix element. The muon-capture rates on deuteron and He-3 are predicted to be 399 +/- 3 sec(-1) and 1494 +/- 21 sec(-1), respectively. The spread accounts for the cutoff sensitivity, as well as uncertainties in the LECs and electroweak radiative corrections. By comparing the calculated and precisely measured rates on He-3, a value for the induced pseudoscalar form factor is obtained in good agreement with the chiral perturbation theory prediction.