Measurements of charged current reactions of ν e on 12 C

Charged current reactions of ${\ensuremath{\nu}}_{e}$ on ${}^{12}\mathrm{C}$ have been studied using a ${\ensuremath{\mu}}^{+}$ decay-at-rest ${\ensuremath{\nu}}_{e}$ beam at the Los Alamos Neutron Science Center. The cross section for the exclusive reaction ${}^{12}\mathrm{C}({\ensuremath{\nu}}_{e}{,e}^{\ensuremath{-}}{)}^{12}{\mathrm{N}}_{\mathrm{g}.\mathrm{s}.}$ was measured to be $(8.9\ifmmode\pm\else\textpm\fi{}0.3\ifmmode\pm\else\textpm\fi{}0.9)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}42}$ ${\mathrm{cm}}^{2}.$ The observed energy dependence of the cross section and angular distribution of the outgoing electron agree well with theoretical expectations. Measurements are also presented for inclusive transitions to ${}^{12}\mathrm{N}$ excited states, ${}^{12}\mathrm{C}({\ensuremath{\nu}}_{e}{,e}^{\ensuremath{-}}{)}^{12}{\mathrm{N}}^{*}$ and compared with theoretical expectations. The measured cross section, $(4.3\ifmmode\pm\else\textpm\fi{}0.4\ifmmode\pm\else\textpm\fi{}0.6)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}42}$ ${\mathrm{}\mathrm{cm}}^{2},$ is somewhat lower than previous measurements and than a continuum random phase approximation calculation. It is in better agreement with a recent shell model calculation.