15,330 research outputs found

    Recent CP violation results from Belle

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    We summarize recent results on an array of CP violation measurements performed by the Belle experiment using the data collected near the Y(4S) and Y(5S) resonances at the KEKB asymmetric-energy e+e- collider.Comment: 8 pages, 5 postscript figures, contributed to the Proceedings of the Rencontres de Moriond EW 2012, La Thuile, Aosta valley, Ital

    Charmless Hadronic B Decays at BABAR

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    We report recent measurements of branching fractions and charge asymmetries of charmless hadronic B decays using the data collected with the BABAR detector at the PEP-II asymmetric energy e+e- collider.Comment: 7 pages, 4 postscript figures, 3 tables, contributed to the Proceedings of XII International Conference on Hadron Spectroscopy (HADRON07), Frascati, Ital

    Charm at Belle II - Status and Prospects

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    High-precision flavor physics measurements play a complementary role to the direct searches for new physics by CMS and ATLAS experiments at LHC. Such measurements will be performed with the Belle II detector at the upgraded KEKB accelerator (SuperKEKB) in Japan. The physics potential with emphasis on the charm sector, current status and future prospects of the Belle II experiment are presented in these proceedings.Comment: 8 pages, 3 postscript figures, to appear in the proceedings of the 6th International Workshop on Charm Physics (CHARM 2013

    Looking for Exotica at the B Factories

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    Current experiments at the B factories, designed to perform precision measurements of matter-antimatter asymmetry in the B meson system, have a much broader physics reach especially in the sector of quarkonium spectroscopy. Here we present a minireview on the new charmonium-like states observed at the B factories including the X(3872) and Y(4260).Comment: 12 pages, 8 postscript figures, contributed to the Proceedings of the 17th DAE-BRNS High Energy Physics Symposium, IIT, Kharagpur, Indi

    Exotic, LFV and LNV Decays at the B Factories

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    I review the latest results on exotic, lepton flavor violating (LFV) and lepton number violating (LNV) decays of the B, D mesons and the tau leptons, obtained at the two B-factory experiments, Belle and BaBar. Where appropriate, results from other experiments are also described.Comment: 8 pages, 5 figures, 2 tables, Proceedings of CKM2010, the 6th International Workshop on the CKM Unitarity Triangle, University of Warwick, UK, 6-10 September 201

    CP violation and hints for new physics at the B factories

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    We report the latest results on CP violation measurements and the tantalizing hints of potential new physics effects obtained at the B factories.Comment: 10 pages, 6 postscript figures, contributed to the Proceedings of the 5th International Conference on Flavor Physics (ICFP09), Hanoi, Vietna

    New Hadron Spectroscopy with BABAR

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    We review hadron spectroscopy at BABAR with emphasis on recent results from the studies of the X(3872) state, inclusive charmonia on recoil, double charmonium production, and the broad structure observed at around 4.26 GeV/c^2. These results are preliminary, unless otherwise specified.Comment: 6 pages, 6 postscript figures, contributed to the Proceedings of Frontier Science 200

    Alternative Scenarios for the Fragmentation of a Gluonic Lund String

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    The assumptions in the Lund model suffice to prescribe a unique stochastic process for the fragmentation of a string into a set of hadrons, so long as the string is "flat", ie as long as the state described by the string consists only of a quark and an antiquark stretching a constant force field between them. Emission of gluons causes the string to trace more complicated surfaces in Minkowski space, and some form of generalization of the 1+1 dimensional model is required. One such generalizaiotn has been developed and implemented as a Monte Carlo routine "JETSET" by Torbj\"orn Sj\"ostrand, which has been hightly successful in describing experimental data. But there are theoretical reasons to believe that the fragmentation scheme employed in JETSET is not entirely satisfactory; most notably, non-adherance to the Lund Area law, and certain problems in handling transverse momenta. A few alternative scenarios, which we have examined in detail and implemented in separate computer programs, will be presented here, with comparisons to JETSET in certain simple cases. Our effort has been to preserve the area law for the fragmentation of a gluonic string, while we explored the possibility of allowing the fragmentation process to reshape the string surface slightly.Comment: 7 pages, 3 figures, to appear in the Proceedings of the XXX'th International Symposium on Multiparticle Dynamics (Oct 9-15, 2000), Lake Balaton, Hungar

    Unfolding of event-by-event net-charge distributions in heavy-ion collision

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    We discuss a method to obtain the true event-by-event net-charge multiplicity distributions from a corresponding measured distribution which is subjected to detector effects such as finite particle counting efficiency. The approach is based on the Bayes method for unfolding of distributions. We are able to faithfully unfold back the measured distributions to match with their corresponding true distributions obtained for a widely varying underlying particle production mechanism, beam energy and collision centrality. Particularly the mean, variance, skewness, kurtosis, their products and ratios of net-charge distributions from the event generators are shown to be successfully unfolded from the measured distributions constructed to mimic a real experimental distribution. We demonstrate the necessity to account for detector effects before associating the higher moments of net-charge distributions with physical quantities or phenomena. The advantage of this approach being that one need not construct new observable to cancel out detector effects which loose their ability to be connected to physical quantities calculable in standard theories

    Baryogenesis from primordial tensor perturbations

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    During inflation primordial quantum fluctuations of the spacetime metric become classical and there is a spontaneous CPT violation by the spin connection coupling terms of the metric with fermions. The energy levels of the left and the right chirality neutrinos is split which gives rise to a net lepton asymmetry at equilibrium. A net baryon asymmetry of the same magnitude can be generated from this lepton asymmetry either by a GUT, B−LB-L symmetry or by electroweak sphaleron processes which preserve B+LB+L symmetry. If the amplitude of the primordial tensor perturbations is of the order of 10−610^{-6} (as is expected from inflation models) and the lepton/baryon number violating processes freeze out at the GUT era Td∌1016GevT_d \sim 10^{16} Gev then a baryon number asymmetry of the correct magnitude 10−1010^{-10} can be generated.Comment: 9 pages Latex fil
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