Muon Capture in Helium-3

Abstract

The partial capture rate ${\ensuremath{\mu}}^{\ensuremath{-}}+{\mathrm{He}}^{3}\ensuremath{\rightarrow}{\mathrm{H}}^{3}+\ensuremath{\nu}$ is calculated, including terms through $O(\frac{1}{{M}^{2}})$ and a phenomenological treatment of the exchange effects. The wave function of the three-nucleon system is largely determined by recent analyses of the electromagnetic form factors. The exchange effects are found to be very important: If they are neglected, two sets of values of ${F}_{P}$ consistent with experiment are 0\ifmmode\pm\else\textpm\fi{}3 and 35\ifmmode\pm\else\textpm\fi{}3. Including the exchange effects, $6\ensuremath{\le}\frac{{F}_{P}}{{F}_{A}}\ensuremath{\le}33$.