Measurement of Angular Asymmetries in the Decays B->K*l+l-

TL;DR

This paper presents a detailed angular analysis of B->K*l+l- decays, measuring asymmetries and polarization observables across multiple dilepton mass bins using a large dataset, including the first angular analysis of B+->K*+l+l- decays.

Contribution

It provides the first angular analysis of B+->K*+l+l- decays and reports measurements of asymmetries and polarization in B->K*l+l- decays across five mass bins.

Findings

Measured angular asymmetries and polarization observables.

First angular analysis of B+->K*+l+l- decays.

Results consistent with Standard Model predictions.

Abstract

We study the lepton forward-backward asymmetry AFB and the longitudinal K* polarization FL, as well as an observable P2 derived from them, in the rare decays B->K*l+l-, where l+l- is either e+e- or mu+mu-, using the full sample of 471 million BBbar events collected at the Upsilon(4S) resonance with the Babar detector at the PEP-II e+e- collider. We separately fit and report results for the B+->K*+l+l- and B0->K*0l+l- final states, as well as their combination B->K*l+l-, in five disjoint dilepton mass-squared bins. An angular analysis of B+->K*+l+l- decays is presented here for the first time.