Tau neutrino as a probe of nonstandard interaction

TL;DR

This paper investigates how nonstandard interactions, such as charged Higgs and W' gauge bosons, affect tau neutrino scattering processes and the extraction of neutrino mixing angles in high-energy experiments.

Contribution

It provides a detailed analysis of how new physics modifies tau neutrino scattering cross sections and impacts the measurement of neutrino mixing angles, including polarization effects.

Findings

New physics can significantly alter cross sections and mixing angle measurements.

Form factor effects are important in quantifying deviations.

Tau lepton polarization is affected by nonstandard interactions.

Abstract

We study the $\Delta$-resonance and deep inelastic scattering contributions in the tau-neutrino nucleon scattering $\nu_{\tau}+ N \to \tau^- + X$ and $\bar{\nu}_{\tau}+ N \to \tau^+ + X$ in the presence of a charged Higgs and a $W'$ gauge boson. The new physics effects to the quasielastic process have been discussed in a previous work. The extractions of the atmospheric mixing angle $\theta_{23}$ rely on the standard model cross sections for $\nu_{\tau}+ N \to \tau^- + X$ in $\nu_{\tau}$ appearance experiments. Corrections to the cross sections from the charged Higgs and $W'$ contributions modify the measured mixing angle. We include form factor effects in the new physics calculations and find the deviations of the mixing angle. If high-energy Long Base Line experiments are designed to measure $\theta_{13}$ through tau neutrino appearance, the new physics effects to $\nu_{\tau}+ N \to \tau^- + X$ and $\bar{\nu}_{\tau}+ N \to \tau^+ + X$ can impact the extraction of this mixing angle. Finally, we investigate the new physics effects on the polarization of the $\tau^\mp$ leptons produced in $\nu_\tau (\bar{\nu}_\tau)$ nucleon scattering.