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

In vitro antimicrobial activity of natural toxins and animal venoms tested against Burkholderia pseudomallei

BACKGROUND: Burkholderia pseudomallei are the causative agent of melioidosis. Increasing resistance of the disease to antibiotics is a severe problem in treatment regime and has led to intensification of the search for new drugs. Antimicrobial peptides are the most ubiquitous in nature as part of the innate immune system and host defense mechanism. METHODS: Here, we investigated a group of venoms (snakes, scorpions and honey bee venoms) for antimicrobial properties against two strains of Gram-negative bacteria Burkholderia pseudomallei by using disc-diffusion assay for in vitro susceptibility testing. The antibacterial activities of the venoms were compared with that of the isolated L-amino acid oxidase (LAAO) and phospholipase A(2 )(PLA(2)s) enzymes. MICs were determined using broth dilution method. Bacterial growth was assessed by measurement of optical density at the lowest dilutions (MIC 0.25 mg/ml). The cell viability was measured using tetrazolium salts (XTT) based cytotoxic assay. RESULTS: The studied venoms showed high antimicrobial activity. The venoms of C. adamanteus, Daboia russelli russelli, A. halys, P. australis, B. candidus and P. guttata were equally as effective as Chloramphenicol and Ceftazidime (30 μg/disc). Among those tested, phospholipase A(2 )enzymes (crotoxin B and daboiatoxin) showed the most potent antibacterial activity against Gram-negative (TES) bacteria. Naturally occurring venom peptides and phospholipase A(2 )proved to possess highly potent antimicrobial activity against Burkholderia pseudomallei. The XTT-assay results showed that the cell survival decreased with increasing concentrations (0.05–10 mg/mL) of Crotalus adamanteus venom, with no effect on the cell viability evident at 0.5 mg/mL. CONCLUSION: This antibacterial profile of snake venoms reported herein will be useful in the search for potential antibacterial agents against drug resistant microorganisms like B. pseudomallei

Measurement of the branching fraction ratios and CP asymmetries in B-→ D0 CP K-decays

We present a preliminary study of $B^- \to D^0_{CP} \pi^-$ and $B^- \to D^0_{CP} K^-$ decays, with the $D^0_{CP}$ reconstructed in the CP-odd eigenstates $K_s \pi^0$, $K_s \omega$, in the CP-even eigenstates $K^+ K^-$, $\pi^+ \pi^-$, and in the (non-CP) flavor eigenstate $K^\mp \pi^\pm$. 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

Improved Limits on the Lepton-Flavor Violating Decays τ−→l−l+l−

A search for the neutrinoless, lepton-flavor violating decay of the tau lepton into three charged leptons has been performed using 376     fb − 1 of data collected at an e + e − center-of-mass energy around 10.58 GeV with the BABAR detector at the SLAC PEP-II storage rings. In all six decay modes considered, the numbers of events found in data are compatible with the background expectations. Upper limits on the branching fractions are set in the range ( 4 - 8 ) × 10 − 8 at 90% confidence level

Middle cretaceous foraminifera and biostratigraphy of Western Siberia

7 pages, 4 postscript figures, submitted to PRLWe present partial branching fractions for inclusive charmless semileptonic B decays Bbar --> X_u ell nubar, and the determination of the CKM matrix element |V_{ub}|. The analysis is based on a sample of 383 million Y(4S) decays into B Bbar pairs collected with the BaBar detector at the PEP-II e+ e- storage rings. We select events using either the invariant mass M_X of the hadronic system, the invariant mass squared, q^2, of the lepton and neutrino pair, the kinematic variable P_+ or one of their combinations. We then determine partial branching fractions in limited regions of phase space: Delta B = (1.18 +- 0.09_{stat.} +- 0.07_{sys.} +- 0.01_{theo.}) x 10^{-3} (M_X 8 GeV^2/c^4). Corresponding values of |V_{ub}| are extracted using several theoretical calculations

Measurement of branching fractions and mass spectra of B -> K pi pi gamma (vol 98, art no 211804, 2007)

Contains fulltext : 71970.pdf (publisher's version ) (Open Access)2 p

Search for lepton flavor violation in the decay tau(+/-)-> e(+/-)gamma

A search for the nonconservation of lepton flavor in the decay tau(+/-)-> e(+/-)gamma has been performed with 2.07x10(8) e(+)e(-)->tau(+)tau(-) events collected by the BABAR detector at the SLAC PEP II storage ring at a center-of-mass energy near 10.58 GeV. We find no evidence for a signal and set an upper limit on the branching ratio of B(tau(+/-)-> e(+/-)gamma)< 1.1x10(-7) at 90% confidence level

Measurement of the CP asymmetry and branching fraction of B-0 ->rho K-0(0)

We present a measurement of the branching fraction and time-dependent CP asymmetry of B-0 -> POKO. The results are obtained from a data sample of 227 x 10(6) Y(4S) -> BB decays collected with the BABAR detector at the PEP-II asymmetric-energy B factory at Stanford Linear Accelerator Center. From a time-dependent maximum likelihood fit yielding 111 +/- 19 signal events, we find B(B-0 -> rho K-0(0)) = (4.9 +/- 0.8 +/- 0.9) x 10(-6), where the first error is statistical and the second systematic. We report the measurement of the CP parameters S-rho 0KS0 = 0.20 +/- 0.52 +/- 0.24 and C-rho 0KS0 = 0.64 +/- 0.41 +/- 0.20

Measurement of branching fractions and mass spectra of B -> K pi pi gamma

We present a measurement of the partial branching fractions and mass spectra of the exclusive radiative penguin processes B -> K pi pi gamma in the range m(K pi pi)pi(+)pi(-). Using 232x10(6) e(+)e(-)-> B (B) over bar events recorded by the BABAR experiment at the SLAC PEP-II asymmetric-energy storage ring, we measure the branching fractions B(B+-> K+pi(-)pi(+)gamma)=[2.95 +/- 0.13(stat)+/- 0.20(syst)]x10(-5), B(B-0 -> K+pi(-)pi(0)gamma)=[4.07 +/- 0.22(stat)+/- 0.31(syst)]x10(-5), B(B-0 -> K-0 pi(+)pi(-)gamma)=[1.85 +/- 0.21(stat)+/- 0.12(syst)]x10(-5), and B(B+-> K-0 pi(+)pi(0)gamma)=[4.56 +/- 0.42(stat)+/- 0.31(syst)]x10(-5)

Branching fraction measurements of B+->rho(+)gamma, B-0 ->rho(0)gamma, and B-0 ->omega gamma

We present a study of the decays B+->rho(+)gamma, B-0 ->rho(0)gamma, and B-0 ->omega gamma. The analysis is based on data containing 347x10(6) B (B) over bar events recorded with the BABAR detector at the PEP-II asymmetric B factory. We measure the branching fractions B(B+->rho(+)gamma)=(1.10(-0.33)(+0.37)+/- 0.09)x10(-6) and B(B-0 ->rho(0)gamma)=(0.79(-0.20)(+0.22)+/- 0.06)x10(-6), and set a 90% C.L. upper limit B(B-0 ->omega gamma)(rho/omega)gamma)=(1.25(-0.24)(+0.25)+/- 0.09)x10(-6), from which we determine vertical bar V-td/V-ts vertical bar=0.200(-0.020)(+0.021)+/- 0.015, where the first uncertainty is experimental and the second is theoretical