Probing lepton non-universality in tau neutrino Scattering

TL;DR

This paper investigates potential lepton flavor non-universality in tau neutrino scattering using an effective Lagrangian and leptoquark models, proposing experimental tests at CERN's SHiP to detect new physics effects.

Contribution

It introduces a novel approach to test lepton universality in tau neutrino scattering by using cross section ratios and considers new physics effects within an effective Lagrangian and leptoquark framework.

Findings

Potential observable effects of new physics at SHiP experiment

Use of cross section ratios to cancel PDF uncertainties

Identification of lepton non-universality signatures in tau neutrino interactions

Abstract

Recently hints of lepton flavor non-universality emerged in the BaBar and LHCb experiments. In this paper we propose tests of lepton universality in $\nu_{\tau}$ scattering. To parametrize the new physics we adopt an effective Lagrangian approach and consider the neutrino deep inelastic scattering processes $\nu_{\tau}+ N \to \tau + X$ and $\nu_{\mu}+ N \to \mu + X$ where we assume the largest new physics effects are in the $\tau$ sector. We also consider an explicit leptoquark model in our calculations. In order to make comparison with the standard model and also in order to cancel out the uncertainties of the parton distribution functions, we consider the ratio of total and differential cross sections of tau-neutrino to muon-neutrino scattering. We find new physics effects that can possibly be observed at the proposed Search for Hidden Particles (SHiP) experiment at CERN.