Two Topics in $b$ Physics

Abstract

(1) A simple transversity analysis permits one to separate the P-even and P-odd partial waves in such decays as $B_s\to J/\psi \varphi$ and $B\to J/\psi K^{\ast }$. This method is relevant to the separation of contributions of CP-even and CP-odd final states in $B_s$ decays, and hence to the measurement of a possible lifetime difference between mass eigenstates. (2) The enhancement $\Delta \Gamma ({\Lambda }_b)$ of the ${\Lambda }_b$ decay rate due to four-fermion processes is calculated in terms of the ${\Sigma }_b^{\ast }-{\Sigma }_b$ hyperfine splitting, the $B^{\ast }-B$ hyperfine splitting, and the $B$ meson decay constant $f_B$. Despite a relatively large hyperfine splitting observed by the DELPHI Collaboration, the mechanism falls far short of being able to explain the observed enhancement.

Comments: 11 pages, latex, no figures. Presented at 10th La Thuile Rencontre. DESY preprint no. corrected in heading