ISSN - 00319007, EISSN - 10797114, Physical Review Letters, 2007, vol. 98, p. -
Observation of the decay B0→J/ψη
We report the first observation of B0→J/ψη decay. These results are obtained from a data sample that contains 449×106 BB̄ pairs accumulated at the Υ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. We observe a signal with a significance of 8.1σ and obtain a branching fraction of (9.5±1.7(stat)±0. 8(syst))×10-6. © 2007 The American Physical Society.