25,878 research outputs found

    Search for single production of the vector-like top partner at the 14 TeV LHC

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    The new heavy vector-like top partner~(TT) is one of typical features of many new physics models beyond the standard model. In this paper we study the discovery potential of the LHC for the vector-like TT-quark both in the leptonic TbWT\to bW and TtlepZlepT\to t_{\rm lep}Z_{\rm lep} (trilepton) channels at s=14\sqrt{s}= 14 TeV in the single production mode. Our analysis is based on a simplified model including a SU(2)LSU(2)_L singlet with charge 2/32/3 with only two free parameters, namely the TWbTWb coupling parameter gg^{\ast} and the top partner mass mTm_T. The 2σ2\sigma exclusion limits, 3σ3\sigma evidence and the 5σ5\sigma discovery reach in the parameter plane of gmTg^{\ast}-m_T, are, respectively, obtained for some typical integrated luminosity at the 14 TeV LHC. Finally we analyze the projected sensitivity in terms of the production cross section times branching fraction for two decay channel.Comment: 15 pages, 10 figures, 2 tables. version in EPJ

    Properties of the scalar mesons f0(1370)f_0(1370), f0(1500)f_0(1500) and f0(1710)f_0(1710)

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    In the three-state mixing framework, considering the possible glueball components of η\eta and η\eta^\prime, we investigate the hadronic decays of f0(1370)f_0(1370), f0(1500)f_0(1500) and f0(1710)f_0(1710) into two pseudoscalar mesons. The quarkonia-glueball content of the three states is determined from the fit to the new data presented by the WA102 Collaboration. We find that these data are insensitive to the possible glueball components of η\eta and η\eta^\prime. Furthermore, we discuss some properties of the mass matrix describing the mixing of the isoscalar scalar mesons.Comment: Latex 14 pages including 1 eps figur

    Number-resolved master equation approach to quantum transport under the self-consistent Born approximation

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    We construct a particle-number(n)-resolved master equation (ME) approach under the self-consistent Born approximation (SCBA) for quantum transport through mesoscopic systems. The formulation is essentially non-Markovian and incorporates the interlay of the multi-tunneling processes and many-body correlations. The proposed n-SCBA-ME goes completely beyond the scope of the Born-Markov master equation, being applicable to transport under small bias voltage, in non-Markovian regime and with strong Coulomb correlations. For steady state, it can recover not only the exact result of noninteracting transport under arbitrary voltages, but also the challenging nonequilibrium Kondo effect. Moreover, the n-SCBA-ME approach is efficient for the study of shot noise.We demonstrate the application by a couple of representative examples, including particularly the nonequilibrium Kondo system.Comment: arXiv admin note: substantial text overlap with arXiv:1302.638

    Role of quark-interchange processes in evolution of mesonic matter

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    We divide the cross section for a meson-meson reaction into three parts. The first part is for the quark-interchange process, the second for quark-antiquark annihilation processes and the third for resonant processes. Master rate equations are established to yield time dependence of fugacities of pions, rhos, kaons and vetor kaons. The equations include cross sections for inelastic scattering of pions, rhos, kaons and vector kaons. Cross sections for quark-interchange-induced reactions, that were obtained in a potential model, are parametrized for convenient use. The number densities of pion and rho (kaon and vector kaon) are altered by quark-interchange processes in equal magnitudes but opposite signs. The master rate equations combined with the hydrodynamic equations for longitudinal and transverse expansion are solved with many sets of initial meson fugacities. Quark-interchange processes are shown to be important in the contribution of the inelastic meson-meson scattering to evolution of mesonic matter.Comment: 28 pages, 1 figure, 8 table
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