35,637 research outputs found

    Direct test of time reversal invariance violation in B mesons

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    In this letter we reinterpret and reanalyze the available data of the B meson factories showing the existence of direct experimental evidence of time reversal invariance violation in B mesons. This reinterpretation consists of using the available observables to define a new observable which, in a model independent way and without assuming CPT invariance, compares a transition between a B0B^0 and a here-defined BαB_\alpha-state, with its time reversed transition. The observable then offers a direct way to probe time reversal invariance and it is therefore independent of any conclusion obtained from current experimental information on CP violation and CPT invariance. As far as the authors are concerned, this is the first direct evidence of time reversal invariance violation in B mesons and also the first one obtained from decaying particles whose mean life time difference is negligible.Comment: 9 pages, no figures. Refined version matching published article in Modern Physics Letters

    Standard Model Higgs and Top Mass Measurements at the Tevatron

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    A summary of the present Standard Model Higgs search and measurement of top quark mass at the Tevatron are presented. The sensitivity of the present Higgs search at the Tevatron is limited by statistics to a cross section approximately two orders of magnitude higher than the predicted cross section for Standard Model Higgs production. With 30/fb of integrated luminosity, the Tevatron offers an unique potential discovery window for the Standard Model Higgs mass up to 130 GeV before LHC era. The study of top at the Tevatron has moved from discovery phase to one of characterizing its properties. The combined result of top quark mass is 174.3+- 5.1 GeV.Comment: 7 pages, latex source-file, 5 figures as ps-file. Talk given at The Division of Particles and Fields Conference 1999, January 5-9, 1999, UCLA, US

    Quark and lepton mass matrices with A4A_4 family symmetry

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    Realistic quark masses and mixing angles are obtained applying the successful A4A_4 family symmetry for leptons, motivated by the quark-lepton assignments of SU(5). The A4A_4 symmetry is suitable to give tri-bimaximal neutrino mixing matrix which is consistent with current experimental data. We study new scenario for the quark sector with the A4A_4 symmetry.Comment: 16 pages, 2 figures, Talk given at International Workshop on Neutrino Masses and Mixings, Shizuoka, Japan, 17-19 December 200

    Search for Rare b-hadron Decays at CDF

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    We report on searches for B^0_s to \mu^+ \mu^-, B^0_d to \mu^+ \mu^- decays and b to s \mu^+\mu^- transitions in exclusive decays of B mesons. Using 2 fb^{-1} of data collected by the CDF II detector we find upper limits on the branching fractions B(B^0_s to \mu^+ \mu^-) < 5.8 x 10^{-8} and B(B^0_d to \mu^+ \mu^-) < 1.8 x 10^{-8} at 95% confidence level. Using 924 pb^{-1} of data we measure the branching fractions B(B^+ to \mu^+ \mu^- K^+) = (0.60 \pm 0.15 \pm 0.04) x 10^{-6}, B(B^0_d to \mu^+ \mu^- K^{*0}) = (0.82 \pm 0.31 \pm 0.10) x 10^{-6} and the limit B(B^0_s to \mu^+ \mu^- phi)/B(B^0_s to J/\psi\phi) < 2.61(2.30) x 10^{-3} at 95(90)% confidence level.Comment: 3 pages, 5 figures, conference proceedings to the 2007 Europhysics Conference on High Energy Physics (Manchester, July 2007

    Charm mixing in the Standard Model and beyond

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    The motivation most often cited in searches for D0-anti-D0 mixing and CP-violation in charm system lies with the possibility of observing a signal from New Physics which dominates that from the Standard Model. We review recent theoretical predictions and experimental constraints on D0-anti-D0 mixing parameters, concentrating on possible effects of New Physics.Comment: 8 pages, 2 figures, Invited talk at International Workshop on Tau-Charm Physics (Charm 2006), Beijing, China, 5-7 Jun 200

    Dynamics of strong and radiative decays of Ds-mesons in the hadrogenesis conjecture

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    The positive parity scalar Ds0_{s0}^*(2317) and axial-vector Ds1_{s1}^*(2460) charmed strange mesons are generated by coupled-channel dynamics through the s-wave scattering of Goldstone bosons off the pseudoscalar and vector D(Ds_s)-meson ground states. The specific masses of these states are obtained as a consequence of the attraction arising from the Weinberg-Tomozawa interaction in the chiral Lagrangian. Chiral corrections to order Qχ2_\chi^2 are calculated and found to be small. The Ds0_{s0}^*(2317) and Ds1_{s1}^*(2460) mesons decay either strongly into the isospin-violating π0\pi^0Ds_s and π0\pi^0Ds_s^* channels or electromagnetically. We show that the π0\pi^0-η\eta and (K0^0D+^+-K+^+D0^0) mixings act constructively to generate strong widths of the order of 140 keV and emphasize the sensitivity of this value to the KDKD component of the states. The one-loop contribution to the radiative decay amplitudes of scalar and axial-vector states is calculated using the electromagnetic Lagrangian to chiral order Qχ2_\chi^2. We show the importance of taking into account processes involving light vector mesons explicitly in the dynamics of electromagnetic decays. The radiative width are sensitive to both ηDs\eta D_s and KDKD components, hence providing information complementary to the strong widths on the positive parity DsD_s-meson structure.Comment: 4 pages, Invited Contribution to QNP09, Beijing, September 21-26, 200

    Lepton flavor violating liljγγl_i\to l_j \gamma\gamma decays induced by scalar unparticle

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    We study the radiative lepton flavor violating l_i -> l_j \gamma\gamma decays in the case that the lepton flavor violation is induced by the scalar unparticle mediation. We restrict the scaling dimension d_u and the scalar unparticle-photon-photon coupling by using the experimental upper limit of the branching ratio of the decay \mu -> e \gamma\gamma. Furthermore, we predict the BRs of the other radiative decays by using the restrictions we get. We observe that the measurements of upper limits of BRs of these decays ensure considerable information for testing the possible signals coming from unparticle physicsComment: 10 pages, 5 figures, 1 tabl

    Dynamics of strong and radiative decays of Ds mesons

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    The positive parity scalar Ds0_{s0}^*(2317) and axial-vector Ds1_{s1}^*(2460) charmed strange mesons are generated by coupled-channel dynamics through the s-wave scattering of Goldstone bosons off the pseudoscalar and vector D(Ds_s)-meson ground states. The attraction leading to the specific masses of these states reflects the chiral symmetry breaking scale which characterizes the Weinberg-Tomozawa interaction in the chiral Lagrangian. Chiral corrections to order Qχ2_\chi^2 are calculated and found to be small. The Ds0_{s0}^*(2317) and Ds1_{s1}^*(2460) mesons decay either strongly into the isospin-violating π0\pi^0Ds_s and π0\pi^0Ds_s^* channels or electromagnetically. We show that the π0\pi^0-η\eta and (K0^0D+^+-K+^+D0^0) mixings act constructively to generate strong widths of the order of 140 keV. The one-loop contribution to the radiative decay amplitudes of scalar and axial-vector states is calculated using the electromagnetic Lagrangian to chiral order Qχ2_\chi^2. We show the importance of taking into account processes involving light vector mesons explicitly in the dynamics of electromagnetic decays to obtain a satisfactory description of the available data.Comment: Contribution to the Meson 2008 Conference, June 6-10, Cracow, Polan

    Cross-Correlation-Function-Based Multipath Mitigation Method for Sine-BOC Signals

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    Global Navigation Satellite Systems (GNSS) positioning accuracy indoor and urban canyons environments are greatly affected by multipath due to distortions in its autocorrelation function. In this paper, a cross-correlation function between the received sine phased Binary Offset Carrier (sine-BOC) modulation signal and the local signal is studied firstly, and a new multipath mitigation method based on cross-correlation function for sine-BOC signal is proposed. This method is implemented to create a cross-correlation function by designing the modulated symbols of the local signal. The theoretical analysis and simulation results indicate that the proposed method exhibits better multipath mitigation performance compared with the traditional Double Delta Correlator (DDC) techniques, especially the medium/long delay multipath signals, and it is also convenient and flexible to implement by using only one correlator, which is the case of low-cost mass-market receivers

    The XYZs of Charmonium at BES

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    This contribution reviews some recent developments in charmonium spectroscopy, and discusses related theoretical predictions. The spectrum of states, strong decays of states above open charm threshold, electromagnetic transitions, and issues related to the recent discoveries of the "XYZ" states are discussed. Contributions that BES can make to our understanding of charmonium and related states are stressed in particular.Comment: 5 pages, 1 eps figure. Invited contribution to the International Workshop on Tau-Charm Physics Charm2006 (5-7 June 2006, Beijing, China
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