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) / dE_p $ and $ d\lambda_\mathrm{ cap}^d (E_d) / dE_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.
Categories: nucl-ex