  One of the exciting results in flavor physics in recent times is the
$R_D$/$R_{D^*}$ puzzle. The measurements of these flavor ratios performed by
the B-factory experiments, BaBar and Belle, and the LHCb experiment are about
$4\sigma$ away from the Standard Model expectation. These measurements indicate
that the mechanism of $b\rightarrow c\tau\bar{\nu}$ decay is not identical to
that of $b\rightarrow c(\mu/e)\bar{\nu}$. This charge lepton universality
violation is particularly intriguing because these decays occur at tree level
in the Standard Model. In particular, we expect a moderately large new physics
contribution to $b\rightarrow c\tau\bar{\nu}$. The different types of new
physics amplitudes, which can explain the $R_D$/$R_{D^*}$ puzzle, have been
identified previously. In this letter, we show that the polarization fractions
of $\tau$ and $D^*$ and the angular asymmetries $A_{FB}$ and $A_{LT}$ in
$B\rightarrow D^*\tau\bar{\nu}$ decay have the capability to uniquely identify
the Lorentz structure of the new physics. A measurement of these four
observables will lead to such an identification.
