Towards Probing the Diffuse Supernova Neutrino Background in All Flavors

Abstract

Fully understanding the average core-collapse supernova requires detecting the diffuse supernova neutrino background (DSNB) in all flavors. While the DSNB $\bar{\nu}_e$ flux is near detection, and the DSNB $\nu_e$ flux has a good upper limit and prospects for improvement, the DSNB $\nu_x$ (each of $\nu_\mu, \nu_\tau, \bar{\nu}_\mu, \bar{\nu}_\tau$) flux has a poor limit and heretofore had no clear path for improved sensitivity. We show that a succession of xenon-based dark matter detectors -- XENON1T (completed), XENONnT/LUX-ZEPLIN (running), and DARWIN (proposed) -- can dramatically improve sensitivity to DSNB $\nu_x$ the neutrino-nucleus coherent scattering channel. XENON1T could match the present sensitivity of $\sim 10^3 \; \mathrm{cm}^{-2}~\mathrm{s}^{-1}$ per $\nu_x$ flavor, XENONnT/LUX-ZEPLIN would have linear improvement of sensitivity with exposure, and a long run of DARWIN could reach a flux sensitivity of $\sim 10 \; \mathrm{cm}^{-2}~\mathrm{s}^{-1}$. Together, these would also contribute to greatly improve bounds on non-standard scenarios. Ultimately, to reach the standard flux range of $\sim 1 \; \mathrm{cm}^{-2}~\mathrm{s}^{-1}$, even larger exposures will be needed, which we show may be possible with the series of proposed lead-based RES-NOVA detectors.