Observation and study of bottom-meson decays to a charm meson, a proton-antiproton pair, and pions

Bottom-meson decays with baryons show two unusual features---the branching fractions are enhanced for multibody decays and the baryon-antibaryon subsystem recoils against the other decay products---and their reasons are not yet well understood. Moreover, measurements using explicit reconstruction techniques constitute only about 1% out of about 8% of such decays.;This Dissertation reports the study of ten bottom-meson decays (labeled 0-9) to a proton-antiproton pair, a charm meson, and a system of up to two pions, viz., (0)B¯0→D 0pp¯, (1)B¯0→ D*0pp¯, (2)B¯ 0→D+pp¯pi -, (3)B¯0→D* +pp¯pi-, (4)B¯ 0→D0 pp¯pi-pi+, (5)B¯ 0→D*0 pp¯pi-pi+, (6)B -→D0pp¯pi -, (7)B-→D* 0pp¯pi-, (8)B -→D+pp¯pi -pi-, and (9)B-→ D*+pp¯pi-pi -, using the BABAR Experiment's 455x106 BB¯ pairs produced with the PEP-II asymmetric-energy e+e- collider at the Stanford Linear Accelerator Center. Four of the modes (0--3) are studied with improved statistics compared to previous studies; six of the modes (4--9) are observed for the first time. For (9), the charged track multiplicity is among the highest for a fully-reconstructed heavy-flavor meson.;The B branching fractions, in units of 10-4 are (using the above labels) (0) 1.02+/-0.04+/-0.05, (1) 0.97+/-0.07+/-0.09, (2) 3.32+/-0.10+/-0.27, (3) 4.55+/-0.16+/-0.37, (4) 2.99+/-0.21+/-0.44, (5) 1.91+/-0.36+/-0.29, (6) 3.72+/-0.11+/-0.23, (7) 3.73+/-0.17+/-0.39, (8) 1.66+/-0.13+/-0.27, and (9) 1.86+/-0.16+/-0.18, where the errors are statistical and systematic, respectively. The 3-body values are suppressed compared to the 4-body, while the 5-body are between the two.;The kinematic distributions shows several features. The proton-antiproton system in the decay is seen recoiling for 3- and 4-body, but not 5-body distributions. Moreover, the 3-body dalitz plots show non-overlapping threshold enhancements in M(pp¯) and M( D(*)0p). The 4-body decays show a narrow peak in M(ppi-) with mass (1497.4+/-3.0+/-0.9)MeV/c2 and full width (47+/-12+/-4)MeV, where the errors are statistical and systematic, respectively. The 5-body decays show distributions similar to expectations from phase-space decay models.