Search for the decay of a B0 or ¯B0 meson to ¯K*0K0 or K*0¯K0

Abstract

We present a search for the decay of a B 0 or ¯¯¯ B 0 meson to a ¯¯¯¯ K * 0 K 0 or K * 0 ¯¯¯¯ K 0 final state, using a sample of approximately 232 × 10 6 B ¯¯¯ B events collected with the BABAR detector at the PEP-II asymmetric energy e + e − collider at SLAC. The measured branching fraction is B ( B 0 → ¯¯¯¯ K * 0 K 0 ) + B ( B 0 → K * 0 ¯¯¯¯ K 0 ) = ( 0.2 + 0.9 + 0.1 − 0.8 − 0.3 ) × 10 − 6 . We obtain the following upper limit for the branching fraction at 90% confidence level: B ( B 0 → ¯¯¯¯ K * 0 K 0 ) + B ( B 0 → K * 0 ¯¯¯¯ K 0 ) < 1.9 × 10 − 6 . We use our result to constrain the standard model prediction for the deviation of the C P asymmetry in B 0 → ϕ K 0 from sin  2 β .