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

TL;DR

This paper presents a conceptual design for DaRveX, an experiment to measure low-energy electron neutrino cross sections on lead at J-PARC MLF, aiming to enable new neutrino research avenues.

Contribution

It introduces a novel experimental setup using lead as a target for low-energy $ u_e$ detection, which has not been measured before, and proposes a method to measure the cross section with 20% precision.

Findings

Design of a lead-scintillator detector for $ u_e$-Pb interactions

Projected 20% measurement precision of the cross section

Potential applications in neutrino oscillation and supernova neutrino detection

Abstract

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.