Exploring $R_D$, $R_{D^{\ast}}$ and $R_{J/Ψ}$ anomalies

Abstract

Deviations from the standard model predictions have been reported in various observables concerned with the lepton flavor universality. At present, the deviation of the measured values of $R_D$ and $R_{D^{\ast}}$ from the standard model expectation is exceeded by $2.3σ$ and $3.4σ$, respectively. Very recently LHCb has measured the ratio of branching ratio $R_{J/Ψ} = \mathcal B(B_c \to J/Ψτν)/\mathcal B(B_c \to J/Ψ\,l\,ν)$, where $l \in (e,\,μ)$, to be $0.71\pm0.17\pm 0.18$ which is at more than $2σ$ away from the standard model prediction. We investigate the anomalies in $R_D$, $R_{D^{\ast}}$, and $R_{J/Ψ}$ using a model independent framework with minimal number of new physics couplings. We find various new physics models that can explain these anomalies within $1σ$.