# A Precise Determination of (Anti)neutrino Fluxes with (Anti)neutrino-Hydrogen Interactions

## TL;DR

This paper introduces a new method to precisely measure neutrino and antineutrino fluxes using exclusive hydrogen interactions, achieving better than 1% accuracy without relying on simulations, which enhances the precision of neutrino experiments.

## Contribution

The paper presents a novel, data-driven technique to determine neutrino fluxes with sub-percent accuracy using exclusive hydrogen interactions, avoiding reliance on models or simulations.

## Key findings

- Achieved better than 1% relative flux accuracy in the relevant energy range.
- Developed techniques to constrain systematic uncertainties directly from data.
- Applicable to near detectors and beam monitoring in long-baseline neutrino experiments.

## Abstract

We present a novel method to accurately determine the flux of neutrinos and antineutrinos, one of the dominant systematic uncertainty affecting current and future long-baseline neutrino experiments, as well as precision neutrino scattering experiment. Using exclusive topologies in $\nu(\bar \nu)$-hydrogen interactions, $\nu_\mu p \to \mu^- p \pi^+$, $\bar \nu_\mu p \to \mu^+ p \pi^-$, and $\bar \nu_\mu p \to \mu^+ n$ with small hadronic energy, we achieve an overall accuracy on the relative fluxes better than 1\% in the energy range covering most of the available flux. Since we cannot rely on simulations nor model corrections at this level of precision, we present techniques to constrain all relevant systematic uncertainties using data themselves. The method can be implemented using the approach we recently proposed to collect high statistics samples of $\nu(\bar \nu)$-hydrogen interactions in a low-density and high-resolution detector, which could serve as part of the near detector complex in a long-baseline neutrino experiment, as well as a dedicated beam monitoring detector.