44,059 research outputs found

    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

    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

    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

    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

    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

    Final stare interaction enhancement effect on the near threshold p\bar p system in B^\pm\to p\bar p \p^\pm decay

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    We discuss the low-mass enhancement effect in the baryon-antibaryon invariant mass in three-body baryonic B decays using final state interactions in the framework of Regge theory. We show that the rescattering between baryonic pair can reproduce the observed mass spectrum.Comment: 7 pages, 11 figure

    Nondecoupling of Heavy Fermions and a Special Yukawa Texture

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    Talk based on work entitled ``Yukawa textures, new physics and nondecoupling,'' done in collaboration with G. C. Branco and J. I. Silva-Marcos, arXiv:hep-ph/0612252, to appear in Phys. Rev. D. In this work we pointed out that New Physics can play an important r\^ ole in rescuing some of the Yukawa texture zero ans\" atze which would otherwise be eliminated by the recent, more precise measurements of VCKMV_{CKM}. We have shown that the presence of an isosinglet vector-like quark which mixes with standard quarks, can render viable a particularly interesting four texture zero Yukawa ansatz. The crucial point is the nondecoupling of the effects of the isosinglet quark, even for arbitrary large values of its mass.Comment: Invited talk at CTP Symposium on Supersymmetry at LHC: Theoretical and Experimental Prospectives, Cairo, Egypt, 11-14 Mar 200

    New neighborhood based rough sets

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    Neighborhood based rough sets are important generalizations of the classical rough sets of Pawlak, as neighborhood operators generalize equivalence classes. In this article, we introduce nine neighborhood based operators and we study the partial order relations between twenty-two different neighborhood operators obtained from one covering. Seven neighborhood operators result in new rough set approximation operators. We study how these operators are related to the other fifteen neighborhood based approximation operators in terms of partial order relations, as well as to seven non-neighborhood-based rough set approximation operators

    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
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