Heavy sterile neutrinos in $B$ decays and new QCD corrections to their semi-hadronic decay rates

TL;DR

This paper explores heavy sterile neutrinos in B decays, providing new QCD corrections to their semi-hadronic decay rates, which are crucial for experimental searches and understanding their lifetimes.

Contribution

It introduces analytic QCD-corrected decay rate calculations for heavy neutrinos, enhancing theoretical predictions for their semi-hadronic decays in B meson processes.

Findings

QCD corrections significantly affect decay rate estimates

Lifetime dependence on mixing angles influences detection prospects

Improved theoretical framework for heavy neutrino decay predictions

Abstract

In modern experiments on flavour physics it is possible to search for the decays of $B$ or $D$ mesons or $\tau$ leptons into final states with heavy neutrinos $N$ (a.k.a. heavy neutral leptons). I present a common study of theorists and experimentalists from Belle II on constraints on $B \rightarrow D^{*} \ell N$. Next I discuss the status of the theory predictions of the various $N$ decay rates. In scenarios in which $N$ interacts with SM particles only through sterile-active neutrino mixing, the dependence of the lifetime on the relevant mixing angles is important to determine whether $N$ decays in the detector or outside. To calculate the inclusive decay rate into semi-hadronic final states reliably one needs to include radiative QCD corrections. I present analytic results for the QCD-corrected decay rates and discuss their phenomenological impact.