Chiral effective field theory predictions for muon capture on deuteron and 3He

الأصل · EN

The muon-capture reactions 2H(μ-,νμ)nn and 3He(μ-,νμ)3H are studied with nuclear strong-interaction potentials and charge-changing weak currents, derived in chiral effective field theory. The low-energy constants (LEC's) cD and cₑ, present in the three-nucleon potential and (cD) axial-vector current, are constrained to reproduce the A=3 binding energies and the triton Gamow-Teller matrix element. The vector weak current is related to the isovector component of the electromagnetic current via the conserved-vector-current constraint, and the two LEC's entering the contact terms in the latter are constrained to reproduce the A=3 magnetic moments. The muon capture rates on deuteron and 3He are predicted to be 399(3) sec⁻¹ and 1494 (21) sec⁻¹, respectively, where the spread accounts for the cutoff sensitivity as well as uncertainties in the LEC's and electroweak radiative corrections. By comparing the calculated and precisely measured rates on 3He, a value for the induced pseudoscalar form factor is obtained in good agreement with the chiral perturbation theory prediction.