367 research outputs found
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
Panorama da ginástica artística feminina brasileira de alto rendimento esportivo: progressão, realidade e necessidades
Morphological changes in distant muscle fibers following thermal injury in Wistar rats
A Precision Measurement of the Lambda_c Baryon Mass
The baryon mass is measured using and decays reconstructed in 232
fb of data collected with the BaBar detector at the PEP-II
asymmetric-energy storage ring. The mass is measured to
be . The dominant systematic uncertainties
arise from the amount of material in the tracking volume and from the magnetic
field strength.Comment: 14 pages, 8 postscript figures, submitted to Phys. Rev.
Measurement of the Ratio of b Quark Production Cross Sections in Antiproton-Proton Collisions at 630 GeV and 1800 GeV
We report a measurement of the ratio of the bottom quark production cross
section in antiproton-proton collisions at 630 GeV to 1800 GeV using bottom
quarks with transverse momenta greater than 10.75 GeV identified through their
semileptonic decays and long lifetimes. The measured ratio
sigma(630)/sigma(1800) = 0.171 +/- .024 +/- .012 is in good agreement with
next-to-leading order (NLO) quantum chromodynamics (QCD)
Drug-Eluting Balloons in the Treatment of Coronary De Novo Lesions: A Comprehensive Review
Measurements of branching fractions and dalitz distributions for B-0 ->(DK0)-K-(*)+/-pi(-/+) decays
We present measurments of the branching fractions for the three-body decays B-0 -> D((*) -/+)K(0)pi(+/-) and their resonant submodes B0 -> D(*)K-/+*(+/-) usinga sample of approximately 88 x 10(6) B (B) over bar pairs collected by the BABER detector at the SLAC PEP-II assymetric energy storage ring. We measure: B(B-0-> D(-/+)K(0)pi(+/-)) = (4.9 +/- 0.7(stat) +/- 0.5(syst)) x 10(-4), B(B-0 -> D*(-/+)K(0)pi(+/-)) = (3.0 +/- 0.7(stat) +/- 0.3(syst)) x 10(-4), B(B-0 -> D-/+K*(+/-)) = (4.6 +/- 0.6(stat) +/- 0.5(syst)) x 10(-4), B(B-0 -> D*K-/+*(+/-) = (3.2 +/- 0.6(stat) +/- 0.3(syst)) x 10(-4). From these measurements we determine the fractions of resonant events to be f(B0 -> D+/-K*(-/+)) = 0.63 +/- 0.08(stat) +/- 0.04(syst) and f(B-0 -> D*K-/+*(+/-)) = 0.72 +/- 0.14(stat) +/- 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
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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