Paolo Franchini

Abstract:

We report a measurement of the time-dependent CP-asymmetry parameters S and C in color-suppressed B0→D(*)0h0 decays, where h0 is a π0, η, or ω meson, and the decays to one of the CP eigenstates K+K-, KS0π0, or KS0ω. The data sample consists of 383×106Υ(4S)→BB̄ decays collected with the BABAR detector at the PEP-II asymmetric-energy B factory at SLAC. The results are S=-0.56±0.23±0.05 and C=-0.23±0.16±0.04, where the first error is statistical and the second is systematic. © 2007 The American Physical Society.

Abstract:

We present updated measurements of CP-violating asymmetries in the decays B0→D*±D and B0→D+D- using (383±4) ×106BB̄ pairs collected by the BABAR detector at the SLAC PEP-II B factory. We determine the time-integrated CP asymmetry AD*±D=0. 12±0.06±0.02, and the time-dependent asymmetry parameters to be CD*+D-=0.18±0.15±0.04, SD*+D-=-0.79±0. 21±0.06, CD*-D+=0.23±0.15±0.04, SD*-D+=-0. 44±0.22±0.06, CD+D-=0.11±0.22±0.07, and SD+D-=-0.54±0.34±0.06, where the first uncertainty is statistical and the second is systematic. © 2007 The American Physical Society.

Abstract:

We present an analysis of inclusive Ωc0 baryon production and decays in 230.5fb-1 of data recorded with the BABAR detector. Ωc0 baryons are reconstructed in four final states (Ω-π+, Ω-π+π0, Ω-π+π+π-, Ξ-K-π+π+) and the corresponding ratios of branching fractions are measured. We also measure the momentum spectrum in the e+e- center-of-mass frame. From the spectrum, we observe Ωc0 production from B decays and in cc̄ events, and extract the two rates of production. © 2007 The American Physical Society.

Abstract:

We have performed a search for the flavor-changing neutral-current decays B→π + -, where + - is either e+e- or μ+μ-, using a sample of 230×106 Υ(4S)→BB̄ decays collected with the BABAR detector. We observe no evidence of a signal and measure the upper limit on the isospin-averaged branching fraction to be B(B→π + -)<9.1×10-8 at 90 confidence level. We also search for the lepton-flavor-violating decays B→πe±μ and measure an upper limit on the isospin-averaged branching fraction of B(B→πe±μ )<9.2×10-8 at 90 confidence level. © 2007 The American Physical Society.

Abstract:

We report observations of CP violation in the decays B0→K+π- and B0→π+π- in a sample of 383×106 Υ(4S)→BB̄ events. We find 4372±82 B0→K+π- decays and measure the direct CP-violating charge asymmetry AKπ=-0.107±0.018(stat)-0.004+0.007(syst) , which excludes the CP-conserving hypothesis with a significance of 5.5 standard deviations. In the same sample, we find 1139±49 B0→π+π- decays and measure the CP-violating asymmetries Sππ=-0.60±0.11(stat)±0.03(syst) and Cππ=-0. 21±0.09(stat)±0.02(syst). CP conservation in B0→π+π- (Sππ=Cππ=0) is excluded at a confidence level 1-C.L.=8×10-8, corresponding to 5.4 standard deviations. © 2007 The American Physical Society.