The impact of neutrino-nucleus interaction modeling on new physics searches

TL;DR

This paper investigates how modeling inaccuracies and tuning procedures of neutrino-nucleus interactions influence the sensitivity of new physics searches in neutrino experiments, emphasizing the need for improved theoretical understanding and transparent tuning practices.

Contribution

It provides a realistic simulation study of the effects of cross section mis-modeling and tuning on new physics searches, specifically analyzing sterile neutrinos and light scalars.

Findings

Tuning does not eliminate sterile neutrino oscillation signatures.

Cross section mis-modeling can bias sensitivity to new physics.

Variations in cross section models dominate sensitivity for light scalars.

Abstract

Accurate neutrino-nucleus interaction modeling is an essential requirement for the success of the accelerator-based neutrino program. As no satisfactory description of cross sections exists, experiments tune neutrino-nucleus interactions to data to mitigate mis-modeling. In this work, we study how the interplay between near detector tuning and cross section mis-modeling affects new physics searches. We perform a realistic simulation of neutrino events and closely follow NOvA's tuning, the first published of such procedures in a neutrino experiment. We analyze two illustrative new physics scenarios, sterile neutrinos and light neutrinophilic scalars, presenting the relevant experimental signatures and the sensitivity regions with and without tuning. While the tuning does not wash out sterile neutrino oscillation patterns, cross section mis-modeling can bias the experimental sensitivity. In the case of light neutrinophilic scalars, variations in cross section models completely dominate the sensitivity regardless of any tuning. Our findings reveal the critical need to improve our theoretical understanding of neutrino-nucleus interactions, and to estimate the impact of tuning on new physics searches. We urge neutrino experiments to follow NOvA's example and publish the details of their tuning procedure, and to develop strategies to more robustly account for cross section uncertainties, which will expand the scope of their physics program.