9,897 research outputs found

    BB-to-Glueball form factor and Glueball production in BB decays

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    We investigate transition form factors of BB meson decays into a scalar glueball in the light-cone formalism. Compared with form factors of BB to ordinary scalar mesons, the BB-to-glueball form factors have the same power in the expansion of 1/mB1/m_B. Taking into account the leading twist light-cone distribution amplitude, we find that they are numerically smaller than those form factors of BB to ordinary scalar mesons. Semileptonic B→GlνˉB\to Gl\bar\nu, B→Gl+l−B\to Gl^+l^- and Bs→Gl+l−B_s\to Gl^+l^- decays are subsequently investigated. We also analyze the production rates of scalar mesons in semileptonic BB decays in the presence of mixing between scalar qˉq\bar qq and glueball states. The glueball production in BcB_c meson decays is also investigated and the LHCb experiment may discover this channel. The sizable branching fraction in Bc→(π+π−)l−νˉB_c\to (\pi^+\pi^-)l^-\bar\nu, Bc→(K+K−)l−νˉB_c\to (K^+K^-)l^-\bar\nu or Bc→(π+π−π+π−)l−νˉB_c\to (\pi^+\pi^-\pi^+\pi^-)l^-\bar\nu could be a clear signal for a scalar glueball state.Comment: 17 pages, 3 figure, revtex

    Constraints from Solar and Reactor Neutrinos on Unparticle Long-Range Forces

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    We have investigated the impact of long-range forces induced by unparticle operators of scalar, vector and tensor nature coupled to fermions in the interpretation of solar neutrinos and KamLAND data. If the unparticle couplings to the neutrinos are mildly non-universal, such long-range forces will not factorize out in the neutrino flavour evolution. As a consequence large deviations from the observed standard matter-induced oscillation pattern for solar neutrinos would be generated. In this case, severe limits can be set on the infrared fix point scale, Lambda_u, and the new physics scale, M, as a function of the ultraviolet (d_UV) and anomalous (d) dimension of the unparticle operator. For a scalar unparticle, for instance, assuming the non-universality of the lepton couplings to unparticles to be of the order of a few per mil we find that, for d_UV=3 and d=1.1, M is constrained to be M > O(10^9) TeV (M > O(10^10) TeV) if Lambda_u= 1 TeV (10 TeV). For given values of Lambda_u and d, the corresponding bounds on M for vector [tensor] unparticles are approximately 100 [3/Sqrt(Lambda_u/TeV)] times those for the scalar case. Conversely, these results can be translated into severe constraints on universality violation of the fermion couplings to unparticle operators with scales which can be accessible at future colliders.Comment: 13 pages, 3 figures. Minor changes due to precision in numerical factors and correction in figure labels. References added. Conclusions remain unchange

    Unparticle Physics in Single Top Signals

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    We study the single production of top quarks in e+e−,epe^+e^-, ep and pppp collisions in the context of unparticle physics through the Flavor Violating (FV) unparticle vertices and compute the total cross sections for single top production as functions of scale dimension d_{\U}. We find that among all, LHC is the most promising facility to probe the unparticle physics via single top quark production processes.Comment: 14 pages, 10 figure

    The all-particle spectrum of primary cosmic rays in the wide energy range from 10^14 eV to 10^17 eV observed with the Tibet-III air-shower array

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    We present an updated all-particle energy spectrum of primary cosmic rays in a wide range from 10^14 eV to 10^17 eV using 5.5 times 10^7 events collected in the period from 2000 November through 2004 October by the Tibet-III air-shower array located at 4300 m above sea level (atmospheric depth of 606 g/cm^2). The size spectrum exhibits a sharp knee at a corresponding primary energy around 4 PeV. This work uses increased statistics and new simulation calculations for the analysis. We performed extensive Monte Carlo calculations and discuss the model dependences involved in the final result assuming interaction models of QGSJET01c and SIBYLL2.1 and primary composition models of heavy dominant (HD) and proton dominant (PD) ones. Pure proton and pure iron primary models are also examined as extreme cases. The detector simulation was also made to improve the accuracy of determining the size of the air showers and the energy of the primary particle. We confirmed that the all-particle energy spectra obtained under various plausible model parameters are not significantly different from each other as expected from the characteristics of the experiment at the high altitude, where the air showers of the primary energy around the knee reaches near maximum development and their features are dominated by electromagnetic components leading to the weak dependence on the interaction model or the primary mass. This is the highest-statistical and the best systematics-controlled measurement covering the widest energy range around the knee energy region.Comment: 19 pages, 20 figures, accepted by Ap
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