Global constraints on muon-neutrino non-standard interactions

TL;DR

This paper combines accelerator and atmospheric neutrino data to improve constraints on non-standard interactions of muon neutrinos with quarks, revealing current limits are weaker than previously thought.

Contribution

It provides a comprehensive analysis that refines existing bounds on muon neutrino non-standard interactions by integrating multiple data sources and re-evaluating past experimental uncertainties.

Findings

Constraints are at the few percent level, weaker than previously believed.

Combining data helps lift parameter degeneracies.

Re-evaluation of NuTeV results affects the bounds.

Abstract

The search for new interactions of neutrinos beyond those of the Standard Model may help to elucidate the mechanism responsible for neutrino masses. Here we combine existing accelerator neutrino data with restrictions coming from a recent atmospheric neutrino data analysis in order to lift parameter degeneracies and improve limits on new interactions of muon neutrinos with quarks. In particular we re-consider the results of the NuTeV experiment in view of a new evaluation of its systematic uncertainties. We find that, although constraints for muon neutrinos are better than those applicable to tau or electron neutrinos, they lie at the few $\times 10^{-2}$ level, not as strong as previously believed. We briefly discuss prospects for further improvement.