Improved Measurement of the Electroweak Penguin Process B->Xsll

TL;DR

This paper reports an improved measurement of the branching fraction for the B->Xsll process, using a large data sample from the Belle detector, providing more precise insights into electroweak penguin decays involving s-quarks.

Contribution

The study presents a more accurate measurement of the B->Xsll branching fraction, utilizing an enhanced reconstruction method and a large dataset from the Belle experiment.

Findings

Measured Br(B->Xsll) = (4.11 ± 0.83 (stat) +0.85-0.81 (syst)) x 10^{-6} for M_ll > 0.2 GeV/c^2.

Used 152 million BB events from Belle detector at KEKB.

Improved precision over previous measurements of the electroweak penguin process.

Abstract

We present an improved measurement of the branching fraction for the electroweak penguin process B->Xsll, where l is an electron or a muon and Xs is a hadronic system containing an s-quark. The measurement is based on a sample of 152*10^6 Upsilon(4S) -> BB events collected with the Belle detector at the KEKB energy asymmetric e+e- collider. The Xs hadronic system is reconstructed from one K^{+-} or K^{0}_{S} and up to four pions, where at most one pion can be neutral. Averaging over both lepton flavors, the inclusive branching fraction is measured to be Br(B->Xsll)=(4.11+-0.83(stat)+0.85-0.81(syst))*10^{-6} for M_ll > 0.2GeV/c2.