Conceptual Design Report of DaRveX: Decay at Rest $ν_e$ + Lead Cross Section Measurement at J-PARC MLF

F. Suekane, Y. Hino, W. Noguchi, T. Tokuraku, N. Kadota, T. Konno, T. Kawasaki, Y. Hoshino, M. Watanabe, Y. Sugaya, M. K. Cheoun

Published 2022-05-24Version 1

DaRveX stands for "Decay at Rest $\nu_e$-Pb cross (X) section measurement". So far, there has not been good target to detect low energy $\nu_e$. Lead is expected to be an excellent $\nu_e$ target because the cross section is expected to be very large and the delayed coincidence technique can be used using final state neutron(s). However, the cross section have not been measured yet. If it is measured, it opens a new window to the future neutrino research field, such as low energy $\nu_e$ oscillation measurements, flavor specific detection of the supernova explosion $\nu_e$ and understanding of $\nu_e$-nucleus interactions. This report explains a conceptual design of DaRveX experiment, which measures cross section of $\nu_e$+Pb charged current interaction, $\nu_e$(E~30MeV)+Pb $\to$ $e^-$+$xn$+Bi; ($x$=1 or 2), using $\nu_e$ from $\mu^+$ decay at rest at J-PARC MLF. The energy and direction of the final state $e^-$ will be measured by using 1-ton scale lead-scintillator sandwich detector. With two years of data taking, the cross section is expected to be measured with 20% of precision.