233 research outputs found

    Measurement of the CP-Violating Asymmetry Amplitude sin2β\beta

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    We present results on time-dependent CP-violating asymmetries in neutral B decays to several CP eigenstates. The measurements use a data sample of about 88 million Y(4S) --> B Bbar decays collected between 1999 and 2002 with the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC. We study events in which one neutral B meson is fully reconstructed in a final state containing a charmonium meson and the other B meson is determined to be either a B0 or B0bar from its decay products. The amplitude of the CP-violating asymmetry, which in the Standard Model is proportional to sin2beta, is derived from the decay-time distributions in such events. We measure sin2beta = 0.741 +/- 0.067 (stat) +/- 0.033 (syst) and |lambda| = 0.948 +/- 0.051 (stat) +/- 0.017 (syst). The magnitude of lambda is consistent with unity, in agreement with the Standard Model expectation of no direct CP violation in these modes

    EuFe2_2As2_2 under high pressure: an antiferromagnetic bulk superconductor

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    We report the ac magnetic susceptibility χac\chi_{ac} and resistivity ρ\rho measurements of EuFe2_2As2_2 under high pressure PP. By observing nearly 100% superconducting shielding and zero resistivity at PP = 28 kbar, we establish that PP-induced superconductivity occurs at TcT_c \sim~30 K in EuFe2_2As2_2. ρ\rho shows an anomalous nearly linear temperature dependence from room temperature down to TcT_c at the same PP. χac\chi_{ac} indicates that an antiferromagnetic order of Eu2+^{2+} moments with TNT_N \sim~20 K persists in the superconducting phase. The temperature dependence of the upper critical field is also determined.Comment: To appear in J. Phys. Soc. Jpn., Vol. 78 No.

    Dalitz plot analysis of the decay B±→K±K±K∓

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    We analyze the three-body charmless decay B-+/-->(KKK -/+)-K-+/--K-+/- using a sample of 226.0 +/- 2.5 million B (B) over bar pairs collected by the BABAR detector. We measure the total branching fraction and CP asymmetry to be B=(35.2 +/- 0.9 +/- 1.6)x10(-6) and A(CP)=(-1.7 +/- 2.6 +/- 1.5)%. We fit the Dalitz plot distribution using an isobar model and measure the magnitudes and phases of the decay coefficients. We find no evidence of CP violation for the individual components of the isobar model. The decay dynamics is dominated by the K+K- S-wave, for which we perform a partial-wave analysis in the region m(K+K-)< 2 GeV/c(2). Significant production of the f(0)(980) resonance, and of a spin zero state near 1.55 GeV/c(2) are required in the isobar model description of the data. The partial-wave analysis supports this observation.This work is supported by 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

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

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    The Physics of the B Factories

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    POTENTIAL FOR PHEROMONE-BASED MATING DISRUPTION OF THE MULLEIN BUG, <i>CAMPYLOMMA VERBASCI</i> (MEYER) (HETEROPTERA: MIRIDAE)

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    AbstractAtmospheric permeation of apple orchards with 16:1 butyl butyrate (BB): 2(E)-crotyl butyrate (CB), the sex pheromone of the mullein bug, Campylomma verbasci (Meyer) (Heteroptera: Miridae), demonstrated potential for pheromone-based mating disruption; atmospheric permeation with single components did not. In traps baited with 16:1 BB:CB, catches of male C. verbasci were 3, 64, and 105% of catches in nontreated controls for disruption treatments of 16:1 BB:CB, CB alone, and BB alone, respectively. With the two-component pheromone as a disruptant, catches of male C. verbasci were significantly reduced relative to controls at dispenser densities of 250, 500, and 1000 per hectare; catches were lowest at 1000 dispensers per hectare. For monitoring of operational trials, pheromone-baited open wing traps hung 1.5 m above ground were judged to be more practical than open wing traps hung 2.5 m above ground, or closed wing traps or white sticky cards at either height. Atmospheric permeation with pheromone did not affect numbers of males and females captured on nonbaited white sticky cards, and trap height did not affect catches of females. However, in pheromone-treated plots, significantly more males were captured on 2.5-m-high nonbaited cards than on 1.5-m-high cards, probably representing incidental catches of males following false trails to pheromone dispensers hung in the upper canopy. This study is the first reported example of pheromone-based disruption of orientation behavior in the Heteroptera.</jats:p
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