The first observation of the decay Bs0→K*0K̄*0 is reported using 35 pb-1 of data collected by LHCb in proton-proton collisions at a centre-of-mass energy of 7 TeV. A total of 49.8±7.5 Bs0→(K+π-)(K-π+) events are observed within ±50 MeV/c2 of the Bs0 mass and 746 MeV/c2<mKπ<1046 MeV/c2, mostly coming from a resonant Bs0→K*0K̄*0 signal. The branching fraction and the CP-averaged K*0 longitudinal polarization fraction are measured to be B(Bs0→K*0K̄*0)=(2.81±0.46(stat.)±0.45(syst.)±0.34(fs/fd))×10-5 and fL=0.31±0.12(stat.)±0.04(syst.). © 2012 CERN.
- Nuclear and High Energy Physics