Measurements of the reactions12C(νμ,μ−)12Ng.s.and12C(νμ,μ−)X

Abstract

Charged current scattering of ${\ensuremath{\nu}}_{\ensuremath{\mu}}$ on ${}^{12}\mathrm{C}$ has been studied using a ${\ensuremath{\pi}}^{+}$ decay-in-flight ${\ensuremath{\nu}}_{\ensuremath{\mu}}$ beam at the Los Alamos Meson Physics Facility. A sample of 56.8 $\ifmmode\pm\else\textpm\fi{}9.6$ events satisfying criteria for the exclusive reaction ${}^{12}{\mathrm{C}(\mathrm{\ensuremath{\nu}}}_{\mathrm{\ensuremath{\mu}}}{,\mathrm{\ensuremath{\mu}}}^{\mathrm{\ensuremath{-}}}{)}^{12}{\mathrm{N}}_{\mathrm{g}.\mathrm{s}.}$ was obtained using a large liquid scintillator neutrino detector. The observed flux-averaged cross section $(6.6\ifmmode\pm\else\textpm\fi{}1.0\ifmmode\pm\else\textpm\fi{}1.0)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}41}{\mathrm{cm}}^{2}$ agrees well with reliable theoretical expectations. A measurement was also obtained for the inclusive cross section to all accessible ${}^{12}\mathrm{N}$ states ${}^{12}\mathrm{C}({\ensuremath{\nu}}_{\ensuremath{\mu}},{\ensuremath{\mu}}^{\ensuremath{-}})X.$ This flux-averaged cross section is $(11.2\ifmmode\pm\else\textpm\fi{}0.3\ifmmode\pm\else\textpm\fi{}1.8)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}40}{\mathrm{cm}}^{2},$ which is approximately half of that given by a recent continuum random-phase approximation calculation.