Explaining the observed deviation in R($D^{(*)}$) in an anomalous 2HDM

TL;DR

This paper investigates how a specific two-Higgs-doublet model can explain the observed deviations in R(D*) and related B decay measurements from standard model predictions, aligning theory with experimental data.

Contribution

It demonstrates that a Flipped/Lepton-Specific 2HDM with enhanced charged Higgs couplings can account for the experimental anomalies in B decay ratios.

Findings

The model aligns with experimental R(D*) and Br(B→τν) within 1σ.

Enhanced charged Higgs couplings explain the deviations.

The extension remains consistent with collider constraints.

Abstract

The reported combined excess of about 4$\sigma$, by BABAR, Belle and LHCb, in the measurements of R($D^{(*)}$) and Br(B $\rightarrow \tau \nu_{\tau}$) from that of the standard model expectation constitute the most significant discrepancy from the standard model in collider experiments thus far(apart from the non zero neutrino masses). Here we analyze the phenomenological implications for these decay modes in a Flipped/Lepton-Specific two-Higg-doublet model with anomalously enhanced charged Higgs coupling to $\tau$/b. We conclude that this extension of the standard model can give results in agreement within 1$\sigma$ of the experimental values for the combination of R($D^{(*)}$) and Br(B $\rightarrow \tau \nu_{\tau}$) data.