Neutrino Induced Charged Current Coherent Pion Production for Constraining the Muon Neutrino Flux at DUNE

TL;DR

This paper proposes using neutrino-induced coherent pion production at DUNE to accurately constrain the muon neutrino flux, leveraging the process's reconstructible kinematics and developing a method to fit flux while accounting for cross section effects.

Contribution

It introduces a novel flux constraint method using $ u_rac{ ext{CC-Coh}}rac{ ext{pi}}$ events, combining cross section measurements and flux fitting in the DUNE experiment.

Findings

Potential to constrain flux normalization to a few percent.

Method leverages simultaneous flux and cross section measurement.

Highlights need for further validation of the Adler relation.

Abstract

We study neutrino induced charge current coherent pion production ($\nu_\mu\text{CC-Coh}\pi$) as a tool for constraining the neutrino flux at the Deep Underground Neutrino Experiment (DUNE). The neutrino energy and flavor in the process can be directly reconstructed from the outgoing particles, making it especially useful to specifically constrain the muon neutrino component of the total flux. The cross section of this process can be obtained using the Adler relation with the $\pi$-Ar elastic scattering cross section, taken either from external data or, as we explore, from a simultaneous measurement in the DUNE near detector. We develop a procedure that leverages $\nu_\mu\text{CC-Coh}\pi$ events to fit for the neutrino flux while simultaneously accounting for relevant effects in the cross section. We project that this method has the statistical power to constrain the uncertainty on the normalization of the flux at its peak to a few percent. This study demonstrates the potential utility of a $\nu_\mu\text{CC-Coh}\pi$ flux constraint, though further work will be needed to determine the range of validity and precision of the Adler relation upon which it relies, as well as to measure the $\pi$-Ar elastic scattering cross section to the requisite precision. We discuss the experimental and phenomenological developments necessary to unlock the $\nu_\mu\text{CC-Coh}\pi$ process as a "standard candle'' for neutrino experiments.