Observation of B0 ---> p anti-p K*0 with a large K*0 polarization
Feb, 200810 pages
Published in:
- Phys.Rev.Lett. 100 (2008) 251801
e-Print:
- 0802.0336 [hep-ex]
Report number:
- BELLE-PREPRINT-2008-5,
- KEK-PREPRINT-2007-77
Experiments:
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Abstract: (arXiv)
We observe the decay B0 to p pbar K*0 with a branching fraction of (1.18^{+0.29}_{-0.25} (stat.) \pm 0.11 (syst.)) \times 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 \pm 13 \pm 3)% in the helicity zero state), while the K*+ meson has a (32 \pm 17 \pm 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\pm 0.20\pm 0.02 and -0.01\pm 0.19\pm 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} \pm 0.39) \times 10^{-6} and BF(B0 to p pbar K0) = (2.51^{+0.35}_{-0.29} \pm 0.21) \times 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.Note:
- 11 pages, 4 figures (8 figure files), submitted to Phys.Rev.Lett
- 11.30.Er
- 13.25.Hw
- electron positron: colliding beams
- electron positron: annihilation
- Upsilon(10570): electroproduction
- B: pair production
- B: hadronic decay
- p: pair production
- K*(892): polarization
- B0: branching ratio
References(20)
Figures(8)