ISSN - 15507998, Physical Review D - Particles, Fields, Gravitation and Cosmology, 2009, vol. 80, p. -
Observation of B+→pΛ̄π+π- at Belle
We study charmless B+ meson decays to the pΛ̄π+π- final state using a 605fb-1 data sample collected at the Υ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. There are significant signals found with the pΛ̄ mass peaking near threshold. The observed branching fraction for nonresonant B+→pΛ̄π+π - is (5.92-0.84+0.88(stat)±0.69(syst))×10-6 with a significance of 9.1 standard deviations. We also observe the intermediate three-body decay B+→pΛ̄ρ0 with a branching fraction of (4.78-0.64+0.67(stat) ±0.60(syst))×10-6 and a significance of 9.5 standard deviations, and find a hint of a B+→pΛ̄f2(1270) signal. No other intermediate three-body decay is found in this study. © 2009 The American Physical Society.