14,657 research outputs found

    Could we learn more about HERA high Q2Q^2 anomaly from LEP200 and TEVATRON? R-parity violation scenario

    Get PDF
    The excess of high Q2Q^2 events at HERA reported in the early 1997 by H1 and ZEUS collaborations has become the subject of extensive studies in the framework of several models related to new physics. Here we concentrate on the most promising, from our point of view, model describing HERA anomaly. We update our previous analysis and take into account new HERA statistics of the 1997 year. HERA events are considered within the R-parity broken SUSY model for a specific scenario with several non-zero couplings. R-parity broken SUSY with several non-zero couplings could explain both high Q2e++jetsQ^2 e^+ + jets and μ++jets\mu^+ + jets observed at HERA. The consequence of such a particular scenario is the excess of high Q2Q^2 di- or tri-jet events at HERA. The relation of this scenario for LEP and TEVATRON colliders is considered. This study shows that if a squark resonance does take place at HERA, supersymmetry with broken R-parity can be revealed at either LEP200 or TEVATRON in the near future.Comment: 15 pages, LaTeX file with 9 eps figure

    Minimal Supersymmetric Standard Model within CompHEP software package

    Get PDF
    The Minimal Supersymmetric Standard Model is presented as a model for the CompHEP software package as a set of files containing the complete Lagrangian of the MSSM, particle contents and parameters. All resources of CompHEP with a user-friendly interface are now available for the phenomenological study of the MSSM. Various special features of the model are discussed.Comment: 11 pages, LaTeX, submitted to Comp. Phys. Communicatio

    Brane-Localized Goldstone Fermions in Bulk Supergravity

    Full text link
    We construct the action and transformation laws for bulk five-dimensional AdS supergravity coupled to one or two brane-localized Goldstone fermions. The resulting bulk-plus-brane system gives a model-independent description of brane-localized supersymmetry breaking in the Randall-Sundrum scenario. We explicitly reduce the action and transformation laws to spontaneously broken four-dimensional supergravity.Comment: 22 page

    Magnetic Moments of Heavy ΞQ\Xi_{Q} Baryons in Light Cone QCD Sum Rules

    Get PDF
    The magnetic moments of heavy ΞQ\Xi_{Q} baryons containing a single charm or bottom quark are calculated in the framework of light cone QCD sum rules method. A comparison of our results with the predictions of the quark models is presented.Comment: 26 Pages, 8 Figures and 1 Tabl

    Positive and negative-parity flavor-octet baryons in coupled QCD sum rules

    Get PDF
    We apply the method of the QCD sum rule, in which positive- and negative-parity baryons couple with each other, to the flavor-octet hyperons and investigate the parity splittings. We also reexamine the nucleon in the method, which was studied in our previous paper, by carefully choosing the Borel weight. Both in the nucleon and hyperon channels the obtained sum rules turn out to have a very good Borel stability and also have a Borel window, an energy region in which the OPE converges and the pole contribution dominates over the continuum contribution. The predicted masses of the positive- and negative-parity baryons reproduce the experimental ones fairly well in the Λ\Lambda and Σ\Sigma channels, if we assign the Λ(1670)\Lambda(1670) and the Σ(1620)\Sigma(1620) to the parity partners of the Λ\Lambda and the Σ\Sigma, respectively. This implies that the Λ(1405)\Lambda(1405) is not the party partner of the Λ\Lambda and may be a flavor-singlet or exotic state. In the Ξ\Xi channel, the sum rule predicts the mass of the negative-parity state to be about 1.8 GeV, which leads to two possibilities; one is that the observed state with the closest mass, Ξ(1690)\Xi(1690), is the parity partner and the other is that the parity partner is not yet found but exists around 1.8 GeV.Comment: 15 pages, 4 figure

    Perturbation of a lattice spectral band by a nearby resonance

    Full text link
    A soluble model of weakly coupled "molecular" and "nuclear" Hamiltonians is studied in order to exhibit explicitly the mechanism leading to the enhancement of fusion probability in case of a narrow near-threshold nuclear resonance. We, further, consider molecular cells of this type being arranged in lattice structures. It is shown that if the real part of the narrow nuclear resonance lies within the molecular band generated by the intercellular interaction, an enhancement, proportional to the inverse width of the nuclear resonance, is to be expected.Comment: RevTeX, 2 figures within the file. In May 2000 the title changed and some minor corrections have been don

    Light-cone sum rules for the NγΔN\gamma\Delta transitions for real photons

    Full text link
    We examine the radiative ΔγN\Delta \to \gamma N transition at the real photon point Q2=0Q^2=0 using the framework of light-cone QCD sum rules. In particular, the sum rules for the transition form factors GM(0)G_M(0) and REMR_{EM} are determined up to twist 4. The result for GM(0)G_M(0) agrees with experiment within 10% accuracy. The agreement for REMR_{EM} is also reasonable. In addition, we derive new light-cone sum rules for the magnetic moments of nucleons, with a complete account of twist-4 corrections based on a recent reanalysis of photon distribution amplitudes.Comment: 34 pages, 9 figures, revised version, published in Phys. Rev. D, one misplaced reference correcte

    Rigid supersymmetry with boundaries

    Full text link
    We construct rigidly supersymmetric bulk-plus-boundary actions, both in xx-space and in superspace. For each standard supersymmetric bulk action a minimal supersymmetric bulk-plus-boundary action follows from an extended FF- or DD-term formula. Additional separately supersymmetric boundary actions can be systematically constructed using co-dimension one multiplets (boundary superfields). We also discuss the orbit of boundary conditions which follow from the Euler-Lagrange variational principle.Comment: 28 pages, JHEP clas
    corecore