B->tau nu in multi-Higgs models with MFV

TL;DR

This paper investigates how two-Higgs doublet models with minimal flavor violation can significantly enhance the B→τν decay rate beyond the Standard Model prediction, considering various experimental constraints.

Contribution

It demonstrates conditions under which B→τν decay can be substantially increased in multi-Higgs models with MFV, especially at large tanβ and specific symmetry-breaking terms.

Findings

Potential 50% enhancement of BR(B→τν) over SM

Enhancement possible even with heavy Higgs (~1 TeV)

Constraints from other decays are considered

Abstract

We analyse the $B \rightarrow \tau \nu$ decay in a generic two-Higgs doublet model satisfying the MFV hypothesis. In particular, we analyse under which conditions $\BR(B \rightarrow \tau \nu)$ can be substantially enhanced over its SM value, taking into account the constraints of $K \rightarrow \mu\nu$, $B \rightarrow X_s \gamma$, and $B_s \rightarrow \mu^+ \mu^-$. We find that for large $\tan\beta$ values and Peccei-Quinn symmetry breaking terms of $\cO(1/\tan\beta)$ a sizable ($\sim 50%$) enhancement of $\BR(B \rightarrow \tau \nu)$ is possible, even for $m_H \sim 1$ TeV.