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.

arXiv comment11 pages, latex, no figures. Presented at 10th La Thuile Rencontre. DESY preprint no. corrected in heading