356 research outputs found
Observation and study of baryonic B decays: B -> D(*) p pbar, D(*) p pbar pi, and D(*) p pbar pi pi
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.Comment: 28 pages, 90 postscript figures, submitted to LP0
Search for rare quark-annihilation decays, B --> Ds(*) Phi
We report on searches for B- --> Ds- Phi and B- --> Ds*- Phi. In the context
of the Standard Model, these decays are expected to be highly suppressed since
they proceed through annihilation of the b and u-bar quarks in the B- meson.
Our results are based on 234 million Upsilon(4S) --> B Bbar decays collected
with the BABAR detector at SLAC. We find no evidence for these decays, and we
set Bayesian 90% confidence level upper limits on the branching fractions BF(B-
--> Ds- Phi) Ds*- Phi)<1.2x10^(-5). These results
are consistent with Standard Model expectations.Comment: 8 pages, 3 postscript figues, submitted to Phys. Rev. D (Rapid
Communications
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Measurement of the branching fraction ratios and CP asymmetries in B-→ D0 CP K-decays
We present a preliminary study of and decays, with the reconstructed in the CP-odd
eigenstates , , in the CP-even eigenstates ,
, and in the (non-CP) flavor eigenstate . Using a
sample of about 382 million Y(4S) decays into BBbar pairs, collected with the
BABAR detector operating at the PEP-II asymmetric-energy B Factory at SLAC, we
measure the ratios of the branching fractions R_CP+- and the direct CP
asymmetries A_CP+-. The results are:
R_CP- = 0.81 \pm 0.10 (stat) \pm 0.05 (syst)
R_CP+ = 1.07 \pm 0.10 (stat) \pm 0.04 (syst)
A_CP- = -0.19 \pm 0.12 (stat) \pm 0.02 (syst)
A_CP+ = 0.35 \pm 0.09 (stat) \pm 0.05 (syst
Observation of CP violation in B ->eta/K-0 decays
We present measurements of the time-dependent CP-violation parameters S and C in B-0 -> eta K-'(0) decays. The data sample corresponds to 384 x 10(6) B (B) over bar pairs produced by e(+)e(-) annihilation at the Upsilon(4S). The results are S = 0.58 +/- 0.10 +/- 0.03 and C = -0.16 +/- 0.07 +/- 0.03. We observe mixing-induced CP violation with a significance of 5.5 standard deviations in this b -> s penguin dominated mode
Measurement of branching fractions and resonance contributions for B-0 ->(D)over-bar(0)K(+)pi(-) and search for B-0 ->(DK+)-K-0 pi(-) decays
Using 226x10(6) Upsilon(4S)-> B (B) over bar events collected with the BABAR detector at the PEP-II e(+)e(-) storage ring at the Stanford Linear Accelerator Center, we measure the branching fraction for B-0->(D) over bar (0)K(+)pi(-), excluding B-0-> D*-K+, to be B(B-0->(0)K(+)pi(-))=(88 +/- 15 +/- 9)x10(-6). We observe B-0->(D) over bar K-0(*)(892)(0) and B-0-> D-2(*)(2460)K--(+) contributions. The ratio of branching fractions B(B-0-> D*-K+)/B(B-0-> D(*-)pi(+))=(7.76 +/- 0.34 +/- 0.29)% is measured separately. The branching fraction for the suppressed mode B-0-> D(0)K(+)pi(-) is B(B-0-> D(0)K(+)pi(-))< 19x10(-6) at the 90% confidence level
Measurements of CP-violating asymmetries in B-0 -> a(1)(+/-)(1260)pi(-/+) decays
We present measurements of CP-violating asymmetries in the decay B-0 -> a(1)(+/-)(1260)pi(-/+) with a(1)(+/-)(1260)->pi(-/+)pi(+/-)pi(+/-). The data sample corresponds to 384x10(6) B(b) over bar pairs collected with the BABAR detector at the PEP-II asymmetric B factory at SLAC. We measure the CP-violating asymmetry A(CP)(a1 pi)=-0.07 +/- 0.07 +/- 0.02, the mixing-induced CP violation parameter S-a1 pi=0.37 +/- 0.21 +/- 0.07, the direct CP violation parameter C-a1 pi=-0.10 +/- 0.15 +/- 0.09, and the parameters Delta C-a1 pi=0.26 +/- 0.15 +/- 0.07 and Delta S-a1 pi=-0.14 +/- 0.21 +/- 0.06. From these measured quantities we determine the angle alpha(eff)=78.6 degrees +/- 7.3 degrees
Determinations of vertical bar V-ub vertical bar from inclusive semileptonic B decays with reduced model dependence
We report two novel determinations of vertical bar V-ub vertical bar with reduced model dependence, based on measurements of the mass distribution of the hadronic system in semileptonic B decays. Events are selected by fully reconstructing the decay of one B meson and identifying a charged lepton from the decay of the other B meson from Y(4S) -> B (B) over bar events. In one approach, we combine the inclusive (B) over bar -> X(u)l (v) over bar rate, integrated up to a maximum hadronic mass m(X) X-s gamma photon energy spectrum. We obtain vertical bar V-ub vertical bar = (4.43 +/- 0.38(stat) +/- 0.25(syst) +/- 0.29(theo)) x 10(-3). In another approach we measure the total (B) over bar -> X(u)l (v) over bar rate over the full phase space and find vertical bar V-ub vertical bar = 3.84 +/- 0.70(stat) +/- 0.30(syst) +/- 0.10(theo)) x 10(-3)
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Search for the decay B0→a1±ρ
DOE and NSF (USA), NSERC (Canada), IHEP (China), CEA and CNRS-IN2P3 (France), BMBF and DFG (Germany), INFN (Italy), FOM (The Netherlands), NFR (Norway), MIST (Russia), and PPARC (United Kingdom). Individuals have received support from CONACyT (Mexico), Marie Curie EIF (European Union), the A. P. Sloan Foundation, the Research Corporation, and the Alexander von Humboldt Foundation
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