Transverse $\tau$ polarization in $B_c\to \tau {\bar{\nu }}_{\tau }\gamma$ decay

Abstract

The possible transverse polarization of the $\tau$-lepton, which is $T$-odd and can be used to measure CP-violation, is estimated precisely in the radiative decay mode $B_c\to \tau {\bar{\nu }}_{\tau }\gamma$ with possible parameters for the multi Higgs doublet model and the R-parity violating supersymmetric model. We find that the up-bound of the transverse polarization with possible parameters in the models is at very different levels i.e. it can be $\le 15\sim 23$ for the former but $\le 0.1$ for the latter, and it is accessible experimentally soon.

Comments: 14 pages, latex, 3 figures, appear in J. Phys. G