Opportunities With Decay-At-Rest Neutrinos From Decay-In-Flight Neutrino Beams

TL;DR

This paper explores the potential of using decay-in-flight neutrino beams at Fermilab's NuMI facility for decay-at-rest neutrino studies, highlighting comparable fluxes to spallation sources and discussing experimental prospects.

Contribution

It demonstrates that decay-at-rest neutrino production at NuMI is feasible and comparable to spallation sources, proposing new experimental opportunities at Fermilab.

Findings

Decay-at-rest neutrino fluxes at NuMI are similar to spallation facilities.

Interaction rates in detectors are comparable to existing datasets.

Potential for new measurements at Fermilab long-baseline beam.

Abstract

Neutrino beam facilities, like spallation neutron facilities, produce copious quantities of neutrinos from the decay at rest of mesons and muons. The viability of decay-in-flight neutrino beams as sites for decay-at-rest neutrino studies has been investigated by calculating expected low-energy neutrino fluxes from the existing Fermilab NuMI beam facility. Decay-at-rest neutrino production in NuMI is found to be roughly equivalent per megawatt to that of spallation facilities, and is concentrated in the facility's target hall and beam stop regions. Interaction rates in 5 and 60 ton liquid argon detectors at a variety of existing and hypothetical locations along the beamline are found to be comparable to the largest existing decay-at-rest datasets for some channels. The physics implications and experimental challenges of such a measurement are discussed, along with prospects for measurements at targeted facilities along a future Fermilab long-baseline neutrino beam.