247 research outputs found

    Spin alignment of K(892)±K^*(892)^\pm mesons produced in neutron-carbon interactions

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    A new precise measurements of spin density matrix element ρ00\rho_{00} of K(892)±K^*(892)^{\pm} mesons produced inclusively in neutron-carbon interactions at \~60 GeV have been carried out in the EXCHARM experiment at the Serpukhov accelerator. The values of ρ00\rho_{00} obtained in the transversity frame are 0.424±0.011(stat)±0.018(sys)0.424\pm0.011(stat)\pm0.018(sys) for K(892)+K^*(892)^+ and 0.393±0.025(stat)±0.018(sys)0.393\pm0.025(stat)\pm0.018(sys) for K(892)K^*(892)^-. Significant PTP_T dependence of ρ00\rho_{00} has been observed in K(892)+K^*(892)^+ production.Comment: 8 pages, LaTeX, 3 eps figure

    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

    The Physics of the B Factories

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