Muon capture by 3He nuclei followed by proton and deuteron production

Abstract

The paper describes an experiment aimed at studying muon capture by ${}^3\mathrm{He}$ nuclei in pure ${}^3\mathrm{He}$ and ${\mathrm{D}}_2+{}^3\mathrm{He}$ mixtures at various densities. Energy distributions of protons and deuterons produced via ${\mu }^{-}+{}^3\mathrm{He}\to p+n+n+{\nu }_{\mu }$ and ${\mu }^{-}+{}^3\mathrm{He}\to d+n+{\nu }_{\mu }$ are measured for the energy intervals $10-49$ MeV and $13-31$ MeV, respectively. Muon capture rates, ${\lambda }_{\mathrm{cap}}^p(\Delta E_p)$ and ${\lambda }_{\mathrm{cap}}^d(\Delta E_d)$ are obtained using two different analysis methods. The least--squares methods gives ${\lambda }_{\mathrm{cap}}^p=(36.7\pm 1.2)s^{-1}$, ${\lambda }_{\mathrm{cap}}^d=(21.3\pm 1.6)s^{-1}$. The Bayes theorem gives ${\lambda }_{\mathrm{cap}}^p=(36.8\pm 0.8)s^{-1}$, ${\lambda }_{\mathrm{cap}}^d=(21.9\pm 0.6)s^{-1}$. The experimental differential capture rates, $d{\lambda }_{\mathrm{cap}}^p(E_p)/d{E}_p$ and $d{\lambda }_{\mathrm{cap}}^d(E_d)/d{E}_d$, are compared with theoretical calculations performed using the plane--wave impulse approximation (PWIA) with the realistic NN interaction Bonn B potential. Extrapolation to the full energy range yields total proton and deuteron capture rates in good agreement with former results.

17 pages, 13 figures, accepted for publication in PRA