Evidence for Neutral B Meson Decays to wK*0

TL;DR

This paper reports the first evidence for the decay of neutral B mesons to wK*0, measuring its branching fraction, polarization, and a significant non-resonant decay mode using data from the Belle detector.

Contribution

It provides the first measurement of B0->wK*0 decay properties, including branching fraction and polarization, and observes a large non-resonant decay component.

Findings

Branching fraction B(B0->wK*0) = (1.8 ± 0.7 ± 0.3) x 10^-6 with 3.0σ significance

Longitudinal polarization fraction fL = 0.56 ± 0.29 ± 0.18

Large non-resonant branching fraction B[B->wK+pi-] = (5.1 ± 0.7 ± 0.7) x 10^-6 with 9.5σ significance

Abstract

We present the results of a study of the charmless vector-vector decay B0->wK*0 with 657x10^6 BB(bar) pairs collected with the Belle detector at the KEKB e+e- collider. We measure the branching fraction to be B(B0->wK*0)=[1.8+/-0.7(stat)+/-0.3(syst)]x10^-6 with 3.0sigma significance. We also perform a helicity analysis of the w and K*0 vector mesons, and obtain the longitudinal polarization fraction fL(B0->wK*0)=0.56+/-0.29(stat)+0.18-0.08(syst). Finally, we measure a large non-resonant branching fraction B[B->wK+pi-; M(Kpi)\in(0.755,1.250) GeV/c^2]=[5.1+/-0.7(stat)+/-0.7(syst)]x10^-6 with a significance of 9.5sigma.