Speaker
Dr
Henry Lamm
(University of Maryland)
Description
LHCb has recently presented a measurement of $R(J/\psi)=\mathcal{BR}(B_c^+\rightarrow J/\Psi \tau^+\bar\nu_\tau)/\mathcal{BR}(B_c^+\rightarrow J/\Psi \mu^+\bar\nu_\mu)$. The value, $R(J/\psi)=0.71\pm 0.17\pm 0.18$ is in mild tension with the range of model predictions 0.25-0.28. The model transition form factors dominate the systematic uncertainty of the measurement and limit the predictions to a range of values. To improve this situation, we have undertaken to compute model-independent constraints on the transitions form factors via dispersive methods. This allow for rigorous error estimates to be assigned and $R(J/\psi)$ to be computed.
| hlamm@umd.edu | |
| Funding source | DE-FG02-93ER-40762 |
Primary author
Dr
Henry Lamm
(University of Maryland)
