Constraining the GENIE model of neutrino-induced single pion production using reanalyzed bubble chamber data

TL;DR

This paper reanalyzes bubble chamber data to refine the GENIE neutrino interaction model, reducing uncertainties and improving agreement with experimental measurements for single pion production channels.

Contribution

It extends previous reanalysis to additional channels and provides updated, more accurate GENIE parameters for neutrino interaction modeling.

Findings

Better fit to bubble chamber data with new parameters

Significantly reduced non-resonant background in GENIE

Potential explanation for recent experimental discrepancies

Abstract

The longstanding discrepancy between bubble chamber measurements of $\nu_\mu$-induced single pion production channels has led to large uncertainties in pion production cross section parameters for many years. We extend the reanalysis of pion production data in deuterium bubble chambers where this discrepancy is solved (Wilkinson et al., PRD 90 (2014) 112017) to include the $\nu_{\mu}n\rightarrow \mu^{-}p\pi^{0}$ and $\nu_{\mu}n\rightarrow \mu^{-}n\pi^{+}$ channels, and use the resulting data to fit the parameters of the GENIE (Rein-Sehgal) pion production model. We find a set of parameters that can describe the bubble chamber data better than the GENIE default parameters, and provide updated central values and reduced uncertainties for use in neutrino oscillation and cross section analyses which use the GENIE model. We find that GENIE's non-resonant background prediction has to be significantly reduced to fit the data, which may help to explain the recent discrepancies between simulation and data observed by the MINERvA coherent pion and NOvA oscillation analyses.