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

TL;DR

This paper uses chiral effective field theory to predict muon capture rates on deuteron and helium-3, constraining low-energy constants with nuclear data, and confirms theoretical form factors with experimental measurements.

Contribution

It provides new predictions for muon capture rates using chiral EFT and constrains low-energy constants with experimental data, improving understanding of weak interactions in light nuclei.

Findings

Predicted muon capture rate on deuteron: 399(3) sec^{-1}

Predicted muon capture rate on 3He: 1494(21) sec^{-1}

Induced pseudoscalar form factor agrees with chiral perturbation theory

Abstract

The muon-capture reactions 2H(\mu^-,\nu_\mu)nn and 3He(\mu^-,\nu_\mu)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) 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 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.