One-pion exchange currents effect on partial muon capture rates for1pshell nuclei

Allowed partial transition rates are calculated for muon capture by nuclei with $A=6-14\mathrm{}$. The nuclear 1p shell model is used and the corrections to the impulse approximation due to exchange currents are estimated with the one-pion exchange model. Whereas the capture rates themselves are strongly dependent on the wave functions, similar amount of exchange current corrections are obtained with all nuclear shell model variants. These percentages vary in a smooth way with the mass number from ≈ -2% for $A=6\mathrm{} \mathrm{to} \approx -20\%$ for $A=14\mathrm{}$. It is found that the scalar and tensor parts of the current are responsible for the main contributions to the corrections.