Investigating $R_D$ and $R_{D^{\ast }}$ anomalies in a Left-Right model with an Inverse Seesaw

Abstract

We investigate $R_D$ and $R_{D^{\ast }}$ anomalies in a low scale left-right symmetric model based on $SU(3{)}_C\times SU(2{)}_L\times SU(2{)}_R\times U(1{)}_{B-L}$ with a simplified Higgs sector consisting of only one bidoublet and one $SU(2{)}_R$ doublet. The Wilson coefficients relevant to the transition $b\to c\tau \nu$ are derived by integrating out the charged Higgs $H^{\pm }$ boson, which gives the dominant contributions. We emphasize that the charged Higgs effects, with the complex right-handed quark mixing matrix, can account for both $R_D$ and $R_{D^{\ast }}$ anomalies simultaneously, while adhering to a set of significant constraints including, for instance, $\mathrm{BR}(B_c^{-}\to {\tau }^{-}{\bar{\nu }}_{\tau })$ and $B_{s(d)}-{\bar{B}}_{s(d)}$ mixing. In relation to this, we show that the predicted values of the $D^{\ast }$, $\tau$ longitudinal polarizations and $P_{\tau }(D)$ can be affected for the set of the parameters of the model resolving the $R_{D,D^{\ast }}$ anomalies.

Comments: 29 pages, 6 figures