Neutrinos from Pion Decay at Rest to Probe the Proton Strangeness in an Underground Lab

TL;DR

This paper proposes using neutrinos from pion decay at rest in underground labs to precisely measure the proton's strangeness content via neutral current elastic scattering, achieving significantly improved accuracy.

Contribution

It introduces a novel experimental approach utilizing low-energy neutrinos from pion decay at rest with a scintillating detector to better determine proton strangeness.

Findings

Optimal energy windows identified for analysis.

Expected event counts allow for 10-fold reduction in error.

Feasible with existing detector technology.

Abstract

The study of the neutral current elastic scattering of neutrinos on protons at lower energies can be used as a compelling probe to improve our knowledge of the strangeness of the proton. We consider a neutrino beam generated from pion decay at rest, as provided by a cyclotron or a spallation neutron source and a 1 kton scintillating detector with a potential similar to the Borexino detector. Despite several backgrounds from solar and radioactive sources it is possible to estimate two optimal energy windows for the analysis, one between 0.65-1.1 MeV and another between 1.73-2.2 MeV. The expected number of neutral current events in these two regions, for an exposure of 1 year, is enough to obtain an error on the strange axial-charge 10 times smaller than available at present.