A novel technique for the measurement of the electron neutrino cross section

TL;DR

This paper introduces a new method to measure electron neutrino cross sections by reconstructing large angle positrons from specific kaon decays, aiming for high-precision flux determination.

Contribution

The paper proposes a novel technique using positron reconstruction in decay tunnels to accurately measure electron neutrino fluxes, improving upon current flux uncertainty limitations.

Findings

Potential to achieve ~1% precision in neutrino flux measurement.

Implementation of positron tagging modes for enhanced flux determination.

Discussion of feasibility for event-by-event neutrino tagging.

Abstract

Absolute neutrino cross section measurements are presently limited by uncertainties on $\nu$ fluxes. In this paper, we propose a technique that is based on the reconstruction of large angle positrons in the decay tunnel to identify three-body semileptonic $K^+ \rightarrow e^+ \pi^0 \nu_e$ decays. This tagging facility operated in positron counting mode ("event count mode") can be employed to determine the absolute $\nu_e$ flux at the neutrino detector with ${\cal O}(1\%)$ precision. Facilities operated in "event by event tag mode" i.e. tagged neutrino beams that exploit the time coincidence of the positron at source and the $\nu_e$ interaction at the detector, are also discussed.