A Brief Account of $B\to K^{\ast }{\ell }^{+}{\ell }^{-}$ Decay in Soft-Collinear Effective Theory

Abstract

A brief account of the study of rare B decay $B\to K^{\ast }{\ell }^{+}{\ell }^{-}$ using soft-collinear effective theory (SCET) is presented. Theoretical underpinning of this work is a factorization formula, derived to leading power in $1/m_b$ and valid to all orders in ${\alpha }_s$. Partially integrated branching ratio in the dilepton squared mass range $1{GeV}^2\le q^2\le 7{GeV}^2$ and the forward-backward (FB) asymmetry of the leptons are calculated. For the zero-point of the FB asymmetry, we get $q_0^2=(4.07_{-0.13}^{+0.16}){GeV}^2$. The scale-related uncertainty of $q_0^2$ is improved compared to the earlier estimate of the same.

Comments: 5 pages, 1 figure, requires style file ws-proc10x7-mod.cls; Presented at the XXXIII International Conference on High Energy Physics, Moscow, Russian Federation, 26th July - 2nd August 2006