Observation and study of baryonic B decays: B -> D(*) p pbar, D(*) p pbar pi, and D(*) p pbar pi pi

TL;DR

This study analyzes ten B-meson decay modes involving D(*) mesons, protons, antiprotons, and pions, revealing new decay observations, suppressed branching fractions in certain modes, and detailed kinematic distributions using BaBar data.

Contribution

First observations of six B-meson decay modes involving D(*) p pbar pi pi, with improved measurements of four previously studied modes, and detailed kinematic analysis of decay distributions.

Findings

Six new decay modes observed for the first time.

Branching fractions for 3- and 5-body decays are suppressed compared to 4-body decays.

Narrow peak observed in m(p pi-) mass distribution at 1497 MeV/c2.

Abstract

We present a study of ten B-meson decays to a D(*), a proton-antiproton pair, and a system of up to two pions using BaBar's data set of 455x10^6 BBbar pairs. Four of the modes (B0bar -> D0 p anti-p, B0bar -> D*0 p anti-p, B0bar -> D+ p anti-p pi-, B0bar -> D*+ p anti-p pi-) are studied with improved statistics compared to previous measurements; six of the modes (B- -> D0 p anti-p pi-, B- -> D*0 p anti-p pi-, B0bar -> D0 p anti-p pi- pi+, B0bar -> D*0 p anti-p pi- pi+, B- -> D+ p anti-p pi- pi-, B- -> D*+ p anti-p pi- pi-) are first observations. The branching fractions for 3- and 5-body decays are suppressed compared to 4-body decays. Kinematic distributions for 3-body decays show non-overlapping threshold enhancements in m(p anti-p) and m(D(*)0 p) in the Dalitz plots. For 4-body decays, m(p pi-) mass projections show a narrow peak with mass and full width of (1497.4 +- 3.0 +- 0.9) MeV/c2, and (47 +- 12 +- 4) MeV/c2, respectively, where the first (second) errors are statistical (systematic). For 5-body decays, mass projections are similar to phase space expectations. All results are preliminary.