Transverse Spin Polarization of ${\tau }^{-}$ in ${\bar{B}}^0\to D^{+}{\tau }^{-}\bar{\nu }$ and Charged Higgs Boson

Abstract

The spin of the $\tau$ lepton in the semiletonic process ${\bar{B}}^0\to D^{+}{\tau }^{-}\bar{\nu }$ can be polarized in the direction which is normal to the reaction plane, if the charged Higgs boson exists and its coupling to quarks has a complex phase. We calculate this transverse polarization of the $\tau$ lepton by using the experimentally measured $B$ to $D$ transition form factors.

Comments: 10 pages, 7 figures, 4 references are added