First evidence of coherent $K^{+}$ meson production in neutrino-nucleus scattering

TL;DR

This paper reports the first experimental evidence of neutrino-induced coherent $K^{+}$ meson production in neutrino-nucleus scattering, a rare process suppressed by Cabibbo angle and kinematic factors, observed using MINERvA detector data.

Contribution

It provides the first experimental evidence of coherent $K^{+}$ production in neutrino interactions, expanding understanding of neutrino-nucleus scattering processes.

Findings

First evidence at 3σ significance of coherent $K^{+}$ production

Observation of the process in scintillator tracker data

Use of kinematic reconstruction to identify coherent scattering

Abstract

Neutrino-induced charged-current coherent kaon production, $\nu_{\mu}A\rightarrow\mu^{-}K^{+}A$, is a rare, inelastic electroweak process that brings a $K^+$ on shell and leaves the target nucleus intact in its ground state. This process is significantly lower in rate than neutrino-induced charged-current coherent pion production, because of Cabibbo suppression and a kinematic suppression due to the larger kaon mass. We search for such events in the scintillator tracker of MINERvA by observing the final state $K^+$, $\mu^-$ and no other detector activity, and by using the kinematics of the final state particles to reconstruct the small momentum transfer to the nucleus, which is a model-independent characteristic of coherent scattering. We find the first experimental evidence for the process at $3\sigma$ significance.