2008/02/29 by The Belle Collaboration, J. H. Chen, M. -Z. Wang · 1 citation
Physics and Astronomy · #hep-ex
paper · pdf · doi:10.1103/physrevlett.100.251801
published as Phys.Rev.Lett.100:251801,2008 · 11 pages, 4 figures (8 figure files), submitted to Phys.Rev.Lett
arxiv created 2008/05/30 · arxiv updated 2009/12/01
We observe the decay B0 to p pbar K*0 with a branching fraction of (1.18+0.29-0.25 (stat.) ± 0.11 (syst.)) × 10-6. The statistical significance is 7.2 sigma for the signal in the low ppbar mass region. We study the decay dynamics of B0 to p pbar K*0 and compare it with B+ to p pbar K*+. The K*0 meson is found to be almost 100% polarized (with a fraction of (101 ± 13 ± 3)% in the helicity zero state), while the K*+ meson has a (32 ± 17 ± 9)% fraction in the helicity zero state. The direct CP asymmetries for B0 to p pbar K*0 and B+ to p pbar K*+ are measured to be -0.08± 0.20± 0.02 and -0.01± 0.19± 0.02, respectively. We also study the characteristics of the low mass ppbar enhancements near threshold and the associated angular distributions. In addition, we report improved measurements of the branching fractions BF(B+ to p pbar K*+) = (3.38+0.73-0.60 ± 0.39) × 10-6 and BF(B0 to p pbar K0) = (2.51+0.35-0.29 ± 0.21) × 10-6, which supersede our previous measurements. These results are obtained from a 492 fb-1 data sample collected near the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+ e- collider.