Observation of B0 -> K*0 K*0bar and search for B0 -> K*0 K*0
arXiv:0708.2248 · doi:10.1103/PhysRevLett.100.081801
Abstract
We report the observation of the b -> d penguin-dominated decay B0 -> K*0 K*0bar with a sample of 383.2 +/- 4.2 million BBbar pairs collected with the BaBar detector at the PEP-II asymmetric-energy e^+e^- collider at the Stanford Linear Accelerator Center. The measured branching fraction is Br(B0 -> K*0 K*0bar) = [1.28^{+0.35}_{-0.30} +/- 0.11] x 10^{-6} and the fraction of longitudinal polarization f_L (B0 -> K*0 K*0bar) = 0.80^{+0.10}_{-0.12} +/- 0.06. The first error quoted is statistical and the second systematic. We also obtain an upper limit at the 90% confidence level on the branching fraction for Br(B0 ->K*0 K*0) < 0.41 x 10^{-6}.
7 pages, 5 postscript figures, submitted to Phys. Rev. Lett. The branching fraction now explicitly includes the K*0->K+pi- subdecay fraction