Eur. Phys. J. C (2022) 82: 371
https://doi.org/10.1140/epjc/s10052-022-10342-9

Regular Article - Experimental Physics

Isospin extrapolation as a method to study inclusive $\overline{B}\to X_s{\ell }^{+}{\ell }^{-}$ decays

¹ Université Paris-Saclay, CNRS/IN2P3, IJCLab, 91405, Orsay, France
² University of Zürich, Zürich, Switzerland

^b powen@physik.uzh.ch

Received: 23 June 2021
Accepted: 15 April 2022
Published online: 27 April 2022

Abstract

A novel approach to reconstruct inclusive $\overline{B}\to X_s{\ell }^{+}{\ell }^{-}$ decays is presented. The method relies on isopsin symmetry to extrapolate the semi-inclusive signature $X_b\to K^{+}{\ell }^{+}{\ell }^{-}X$ to the fully inclusive rate in $B^{+}$ and $B^0$ decays. We investigate the possibility to measure branching fractions and other observables such as lepton universality ratios and $CP$ asymmetries. As a proof of concept, fast simulation is used to compare the $X_b\to K^{+}{\ell }^{+}{\ell }^{-}X$ signature with a fully inclusive approach. Several experimental advantages are seen which have the potential to make measurements of inclusive $\overline{B}\to X_s{\ell }^{+}{\ell }^{-}$ decays tractable at a hadron collider.