COHERENT at the Spallation Neutron Source

Abstract

The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory provides an intense, high-quality source of neutrinos from pion decay at rest. This source was recently used for the first measurements of coherent elastic neutrino-nucleus scattering (CEvNS) by the COHERENT collaboration, resulting in new constraints of beyond-thestandard-model physics. The SNS neutrino source will enable further CEvNS measurements, exploration of inelastic neutrino-nucleus interactions of particular relevance for understanding of supernova neutrinos, and searches for accelerator-produced sub-GeV dark matter. Taking advantage of this unique facility, COHERENT's suite of detectors in "Neutrino Alley" at the SNS is accumulating more data to address a broad physics program at the intersection of particle physics, nuclear physics, and astrophysics. This review describes COHERENT's first two CEvNS measurements, their interpretation, and the potential of a future physics program at the SNS.

The COHERENT Experimental Program

“…Flux-averaged CEvNS cross sections as a function of neutron number, from Ref. [9]. The black line assumes unity form factor.…”

Constraining Light Mediators via Detection of Coherent Elastic Solar Neutrino Nucleus Scattering

“…Note that the contribution for Ar is vanishing because of the zero total spin. Vector 36 Ar 38 Ar 40 Ar 70 Ge 72 Ge 74 Ge SM Vector…”

“…On the other hand, the observation of the CEνNS process have important implications on the neutrino floor [26][27][28][29][30][31] in the Dark Matter (DM) direct detection and the observation of astrophysical neutrino fluxes from the supernovae [32][33][34][35][36][37], the collapsing supermassive stars [38] and the primordial black holes [39]. In addition to the observation at spallation neutron sources [40,41], there are also intensive interests in the CEνNS detection from man-made reactor neutrinos [42][43][44][45]. Although no evidence of the reactor neutrino CEνNS process has been observed, there are already interesting limits on a variety of new physics scenarios.…”

Probing neutrino magnetic moments and the XENON1T excess with coherent elastic solar neutrino scattering

“…CEνNS experiments based on the neutrino fluxes from man-made sources including the spallation neutron source [28,29] and nuclear reactors [30][31][32][33][34][35] are promising on providing competitive constraints on a series of the new physics theory. On the other hand, there have already been intensive interests in the observation of astrophysical neutrino fluxes through the CEνNS process, which could be a new probe to supernovae [36][37][38][39][40][41], the collapsing supermassive stars [42] and the primordial black holes [43].…”