Speaker
Description
Recent measurements of $R_D$-$R_{D^*}$ by Belle collaboration are in agreement with the Standard Model predictions. After inclusion of these measurements, the tension between global average and the SM prediction has reduced to $3.1\sigma$. Assuming the new physics Wilson coefficients to be complex, we do a global fit to present $b\rightarrow c\,\tau\,\bar{\nu}$ data. We find that there are only two (three) allowed solutions respecting the upper limit of $\mathcal{B}(B_c\rightarrow \tau\,\bar{\nu})$ to be $30\%$ ($60\%$). We calculate the predictions of $\tau$ polarization fraction and forward-backward asymmetry in $B\rightarrow D\,\tau\,\bar{\nu}$ and forward-backward asymmetry in $B\rightarrow D^*\,\tau\,\bar{\nu}$ for each new physics solution. Further we determine the predictions for CP violating triple product asymmetries in $B\rightarrow D^*\,\tau\,\bar{\nu}$ decay for the allowed solutions. We find that one of the three asymmetries can be enhanced only up to $2-3\%$ due to presence of two of the three new physics solutions.
