Detection of supernova neutrinos by neutrino-proton elastic scattering

We propose that neutrino-proton elastic scattering, ν+→pν+p, can be used for the detection of supernova neutrinos in scintillator detectors. Though the proton recoil kinetic energy spectrum is soft, with Tₚ2E_ν²/Mₚ, 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 νₑ+→pe⁺+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, ν_μ, and ν_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.