Resolved Power Corrections to the Inclusive Decay $\bar{B}\to X_s{\ell }^{+}{\ell }^{-}$

Abstract

We identify the correct power counting of all the variables in the low-$q^2$ window of the inclusive decay $\bar{B}\to X_s{\ell }^{+}{\ell }^{-}$ within the effective theory SCET if a hadronic mass cut is imposed. Furthermore we analyse the resolved power corrections at the order $1/m_b$ in a systematic way. As a special feature, the resolved contributions stay nonlocal when the hadronic mass cut is released. Therefore they represent an irreducible uncertainty independent of the hadronic mass cut.

Comments: 8 pages, 3 figures, based on talks given by T.H. at the Sixth Workshop on Theory, "Phenomenology and Experiments in Flavour Physics", Capri, 11-13 June 2016, and at the MIAPP Scientific Programme "Flavour Physics with High-Luminosity Experiments", Munich, 24 October -18 November 2016, published in the proceedings