---
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 $2.3\sigma$ and $3.4\sigma$, respectively. Very recently LHCb has measured the ratio of branching ratio $R_{J/\Psi} = 
    \mathcal B(B_c \to J/\Psi\tau\nu)/\mathcal B(B_c \to J/\Psi\,l\,\nu)$, where $l \in (e,\,\mu)$, to be $0.71\pm0.17\pm 0.18$ which is at more than $2\sigma$ away from the standard model prediction. We investigate the anomalies in $R_D$, $R_{D^{\ast}}$, and $R_{J/\Psi}$ using a model independent framework with minimal number of new physics couplings. We find various new physics models that can explain these anomalies within $1\sigma$.
author:
- 'Rupak Dutta${}$'
title: 'Exploring $R_D$, $R_{D^{\ast}}$ and $R_{J/\Psi}$ anomalies'
---

Introduction {#int}
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Lepton flavor universality violation has been the center of attention due to the long standing anomalies that persisted in the ratio of branching ratios $R_D$ and $R_{D^{\ast}}$, where $$\begin{aligned}
&&R_{D^{(\ast)}}=\frac{\mathcal B(B \to D^{(\ast)}\tau\nu)}{\mathcal B(B \to D^{(\ast)}l\nu)}\,, \qquad
l \in (e,\,\mu)\,.\end{aligned}$$ Unlike the individual branching ratio of these decay modes, $R_D$ and $R_{D^{\ast}}$ do not suffer from the uncertainties coming from the Cabbibo-Kobayashi-Mashakawa (CKM) matrix elements and the 