531 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
Search for supersymmetric particles in scenarios with a gravitino LSP and stau NLSP
Sleptons, neutralinos and charginos were searched for in the context of
scenarios where the lightest supersymmetric particle is the gravitino. It was
assumed that the stau is the next-to-lightest supersymmetric particle. Data
collected with the DELPHI detector at a centre-of-mass energy near 189 GeV were
analysed combining the methods developed in previous searches at lower
energies. No evidence for the production of these supersymmetric particles was
found. Hence, limits were derived at 95% confidence level.Comment: 31 pages, 14 figure
dOCRL maintains immune cell quiescence in Drosophila by regulating endosomal traffic
Lowe Syndrome is a developmental disorder characterized by eye, kidney, and neurological pathologies, and is caused by mutations in the phosphatidylinositol-5-phosphatase OCRL. OCRL plays diverse roles in endocytic and endolysosomal trafficking, cytokinesis, and ciliogenesis, but it is unclear which of these cellular functions underlie specific patient symptoms. Here, we show that mutation of Drosophila OCRL causes cell-autonomous activation of hemocytes, which are macrophage-like cells of the innate immune system. Among many cell biological defects that we identified in docrl mutant hemocytes, we pinpointed the cause of innate immune cell activation to reduced Rab11-dependent recycling traffic and concomitantly increased Rab7-dependent late endosome traffic. Loss of docrl amplifies multiple immune-relevant signals, including Toll, Jun kinase, and STAT, and leads to Rab11-sensitive mis-sorting and excessive secretion of the Toll ligand SpÄtzle. Thus, docrl regulation of endosomal traffic maintains hemocytes in a poised, but quiescent state, suggesting mechanisms by which endosomal misregulation of signaling may contribute to symptoms of Lowe syndrome
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.
Observation of the Decay B=> J/psi eta K and Search for X(3872)=> J/psi eta
We report the observation of the meson decay
and evidence for the decay , using {90} million
events collected at the \ensuremath{\Upsilon{(4S)}}\xspace resonance
with the detector at the PEP-II asymmetric-energy storage
ring. We obtain branching fractions of )= and
)=. We search for the new narrow mass state, the
X(3872), recently reported by the Belle Collaboration, in the decay B^\pm\to
X(3872)K^\pm, X(3872)\to \jpsi \eta and determine an upper limit of
(B^\pm \to X(3872) K^\pm \to \jpsi \eta K^\pm)
at 90% C.L.Comment: 7 pages and two figures, submitted to Phys. Rev. Lett
Study of B0_s anti-B0_s oscillations and B0_s lifetimes using hadronic decays of B0_s mesons
Oscillations of B0s mesons have been studied in samples selected from about
3.5 million hadronic Z decays detected by DELPHI between 1992 and 1995. One
analysis uses events in the exclusive decay channels: B0s -> Ds- pi+ or Ds- a1+
and B0s -> anti-D0 K- pi+ or anti-D0 K- a1+, where the D decays are completely
reconstructed. In addition, B0s anti-B0s oscillations have been studied in
events with an exclusively reconstructed Ds accompanied in the same hemisphere
by a high momentum hadron of opposite charge. Combining the two analyses, a
limit on the mass difference between the physical B0s states has been obtained:
Delta(m_B0s) > 4.0 ps^{-1} at the 95% C.L. with a sensitivity of Delta(m_B0s)
= 3.2 ps^{-1}. Using the latter sample of events, the B0s lifetime has been
measured and an upper limit on the decay width difference between the two
physical B0s states has been obtained:
tau(B0s) = 1.53^{+0.16}_{-0.15}(stat.) +/- {0.07}(syst.) ps
\Delta\Gamma(B0s)/\Gamma(B0s) < 0.69 at the 95% C.L.
The combination of these results with those obtained using Ds+- lepton-+
sample gives:
Delta(m_B0s) > 4.9 ps^{-1} at the 95% C.L.
with a sensitivity of Delta(m_B0s) = 8.7 ps^{-1}.
tau(B0s) = 1.46 +/- 0.11 ps and \Delta\Gamma(B0s)/\Gamma(B0s) < 0.45 at the
95% C.L.Comment: 42 pages, 13 figure
Observation of a Charmed Baryon Decaying to D0p at a Mass Near 2.94âGeV/c2
A search for charmed baryons decaying to D 0 p reveals two states: the Î c ( 2880 ) + baryon and a previously unobserved state at a mass of [ 2939.8 ± 1.3 ( stat ) ± 1.0 ( syst ) ] â â MeV / c 2 and with an intrinsic width of [ 17.5 ± 5.2 ( stat ) ± 5.9 ( syst ) ] â â MeV . Consistent and significant signals are observed for the K â Ï + and K â Ï + Ï â Ï + decay modes of the D 0 in 287 â â fb â 1 annihilation data recorded by the BABAR detector at a center-of-mass energy of 10.58 GeV. There is no evidence in the D + p spectrum of doubly charged partners. The mass and intrinsic width of the Î c ( 2880 ) + baryon and relative yield of the two baryons are also measured
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