Study of the decay mechanism for B+→pp¯K+ and B+→pp¯π+

Abstract We study the characteristics of the low mass p p¯ enhancements near threshold in the three-body decays B + → p p¯ K + and B + → p p¯ π + . We observe that the proton polar angle distributions in the p p¯ helicity frame in the two decays have the opposite polarity, and measure the forward-backward asymmetries as a function of the p p¯ mass for the p p¯ K + mode. We also search for the intermediate two-body decays, B + → p¯ Δ + + and B + → pΔ ¯ 0 , and set upper limits on their branching fractions. These results are obtained from a 414 fb −1 data sample that contains 449 × 10 6 B B ¯ events collected near the ϒ ( 4 S ) resonance with the Belle detector at the KEKBasymmetric-energy e + e − collider.