New global bounds on heavy neutrino mixing

TL;DR

This paper provides updated bounds on heavy neutrino mixing by analyzing precision and flavor observables, improving constraints on deviations from unitarity in the leptonic mixing matrix.

Contribution

It offers a comprehensive global fit analysis incorporating new experimental results to constrain heavy neutrino mixing with active flavors.

Findings

Stronger bounds on heavy neutrino mixing parameters.

Updated constraints from key observables like $M_W$, $|V_{ud}|$, and $ ext{Gamma}_{ ext{inv}}$.

Enhanced understanding of deviations from unitarity in the leptonic mixing matrix.

Abstract

We present an updated and improved global fit analysis of precision and flavor observables so as to derive constraints on deviations from unitarity in the leptonic mixing matrix. We focus on the case in which these deviations are sourced by heavy neutrinos, such that our results can also be interpreted as bounds on their mixing with the active flavors. Our analysis is motivated by new results on key observables, such as $M_W$, $|V_{ud}|$ and $\Gamma_{\text{inv}}$.