Detection of Supernova Neutrinos by Neutrino-Proton Elastic Scattering

Abstract

We propose that neutrino-proton elastic scattering, $ν+ p \to ν+ p$, can be used for the detection of supernova neutrinos in scintillator detectors. Though the proton recoil kinetic energy spectrum is soft, with $T_p \simeq 2 E_ν^2/M_p$, and the scintillation light output from slow, heavily ionizing protons is quenched, the yield above a realistic threshold is nearly as large as that from $\barν_e + p \to e^+ + n$. In addition, the measured proton spectrum is related to the incident neutrino spectrum, which solves a long-standing problem of how to separately measure the total energy and temperature of $ν_μ$, $ν_τ$, $\barν_μ$, and $\barν_τ$. The ability to detect this signal would give detectors like KamLAND and Borexino a crucial and unique role in the quest to detect supernova neutrinos.