ISSN - 00319007, EISSN - 10797114, Physical Review Letters, 2010, vol. 105, p. -
First measurement of inclusive B→Xsη decays
We report a first measurement of inclusive B→Xsη decays, where Xs is a charmless state with unit strangeness. The measurement is based on a pseudoinclusive reconstruction technique and uses a sample of 657×106BB̄ pairs accumulated with the Belle detector at the KEKB e⊃+e⊃- collider. For MXs<2.6GeV/c2, we measure a branching fraction of [26.1±3.0(stat)-2.1+1.9(syst)-7.1+4. 0(model)]×10-5 and a direct CP asymmetry of AC P=-0.13±0.04-0.03+0.02. Over half of the signal occurs in the range MXs>1.8GeV/c2. © 2010 The American Physical Society.