Study of B → p ¯ p π π

Abstract

Using a data sample of 772 × 10 6

B ¯ B pairs collected on the Υ ( 4 S ) resonance with the Belle detector at the KEKB asymmetric energy e + e − collider, we report the observation of B 0 → p ¯ p π + π − and the first observation of B + → p ¯ p π + π 0 . We measure a decay branching fraction of ( 0.83 ± 0.17 ± 0.17 ) × 10 − 6 in B 0 → p ¯ p π + π − for M π + π − < 1.22

GeV / c 2 with a significance of 5.5 standard deviations. The contribution from B 0 → p ¯ p K 0 is excluded. We measure a decay branching fraction of ( 4.58 ± 1.17 ± 0.67 ) × 10 − 6 for B + → p ¯ p π + π 0 with M π + π 0 < 1.3

GeV / c 2 with a significance of 5.4 standard deviations. We study the difference of the M p ¯ p distributions in B 0 → p ¯ p π + π − and B + → p ¯ p π + π 0 .