Constraints on the charged-current non-standard neutrino interactions induced by the gauge boson $W'$

TL;DR

This paper examines how a hypothetical $W'$ gauge boson could induce charged-current non-standard neutrino interactions and uses various decay processes to set model-independent constraints on these interactions.

Contribution

It provides the first comprehensive, model-independent analysis of constraints on charged-current NSI induced by $W'$ considering multiple decay channels.

Findings

Constraints on leptonic CC NSI are stronger than those involving first-generation quarks.

The most stringent bounds come from the decay $oldsymbol{ ext{mu} ightarrow e ext{gamma}}$.

Pure leptonic CC NSI are more tightly constrained than quark-involving NSI.

Abstract

Many new physics scenarios predict the existence of the extra charged gauge boson $ W'$, which can induce the charged-current (CC) non-standard neutrino interactions (NSI). We investigate the constraints on the CC NSI in model-independent fashion via considering the $ W'$ contributions to the lepton flavor violating (LFV) decays $\ell_{i}\rightarrow \ell_{j}\gamma$, the pure leptonic flavor conservation (FC) decays $\ell_{i}\rightarrow \ell_{j}\nu_{i}\bar{\nu_{j}}$, leptonic decays of charged pion meson, semileptonic $\tau$ decays, and superallowed $\beta$ decays. We find that the constraints on the pure leptonic CC NSI are generally stronger than the ones for the CC NSI with first generation quarks. The most stringent constraints on the CC NSI arise from the LFV decay $\mu \rightarrow e\gamma$.