Study of the decay mechanism for B+ to p pbar K+ and B+ to p pbar pi+

TL;DR

This study investigates the decay mechanisms of B+ mesons into p pbar K+ and p pbar pi+ by analyzing angular distributions, asymmetries, and intermediate states using a large data sample from the Belle detector.

Contribution

It provides new measurements of angular asymmetries and sets upper limits on specific intermediate decay modes in B+ decays, enhancing understanding of decay dynamics.

Findings

Opposite proton polar angle distributions in the two decay modes.

Measured forward-backward asymmetries as a function of ppbar mass.

Set upper limits on B+ to pbar Delta++ and B+ to p Delta0bar branching fractions.

Abstract

We study the characteristics of the low mass ppbar enhancements near threshold in the three-body decays B+ to p pbar K+ and B+ to p pbar pi+. We observe that the proton polar angle distributions in the ppbar helicity frame in the two decays have the opposite polarity, and measure the forward-backward asymmetries as a function of the ppbar mass for the p pbar K+ mode. We also search for the intermediate two-body decays, B+ to pbar Delta++ and B+ to p Delta0bar, and set upper limits on their branching fractions. These results are obtained from a 414 fb^{-1} data sample that contains 449 times 10^6 BBbar events collected near the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+ e- collider.