Neutrino reaction cross sections $({\nu }_{\mu },{\mu }^{-}),$ $\left({\nu }_e{,e}^{-}\right)$ and $\mu$-capture and photoabsorption rates on ${}^{12}\mathrm{C}$ are computed within a large-basis shell-model framework, which included excitations up to $4ħ\omega .$ When ground-state correlations are included with an open p shell the predictions of the calculations are in reasonable agreement with most of the experimental results for these reactions. Woods-Saxon radial wave functions are used, with their asymptotic forms matched to the experimental separation energies for bound states, and matched to a binding energy of 0.01 MeV for unbound states. We obtain, for the neutrino-absorption inclusive cross sections (but excluding the ${}^{12}\mathrm{N}\mathrm{}$ ground-state contribution) $\overline{\sigma }=13.2\mathrm{}\times {10}^{-40}\hspace{0.5em}{\mathrm{cm}}^2$ for the $({\nu }_{\mu },{\mu }^{-})$ decay-in-flight flux in agreement with the LSND datum of $(11.7\mathrm{}\pm 1.8)\times {10}^{-40}\hspace{0.5em}{\mathrm{cm}}^2$ and $\overline{\sigma }=4.1\mathrm{}\times {10}^{-42}\hspace{0.5em}{\mathrm{cm}}^2$ for the $\left({\nu }_e{,e}^{-}\right)$ decay-at-rest flux, less than the experimental result of $(5.4\mathrm{}\pm 0.8)\times {10}^{-42}\hspace{0.5em}{\mathrm{cm}}^2.$

• Received 12 July 1999

DOI:https://doi.org/10.1103/PhysRevC.61.044603