16,425 research outputs found

    Rigid supersymmetry with boundaries

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    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

    WHW_H-pair Production in the Littlest Higgs Model with T parity in next-to-leading order QCD at LHC

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    In the framework of the littlest Higgs model with TT parity, we study the WHW_H-pair production at the CERN Large Hadron Collider up to the QCD next-to-leading order (NLO). The kinematic distributions of final decay products and the theoretical dependence of the cross section on the factorization/renormalization scale are analyzed. We adopt the PROSPINO scheme in the QCD NLO calculations to avoid double counting and keep the convergence of the perturbative QCD description. Our numerical results show that the QCD NLO corrections significantly reduce the scale uncertainty, and enhance the leading order integrated cross section with a KK-factor in the range of ( with the symmetry breaking scale ff varying from 400GeV400 GeV (400GeV400 GeV) to 1.5TeV1.5 TeV (1.0TeV1.0 TeV) at the 14TeV14 TeV (8TeV)(8 TeV) LHC. We find that it is possible to select the signal events of the WHW_H-pair production from the ppW+We+μνeνˉμ+Xpp\to W^+ W^- \to e^+ \mu^-\nu_{e}\bar{\nu}_{\mu}+X background with high ratio of signature over background by taking proper lower limits on transverse momenta, invariant mass of the final charged leptons and the missing transverse momentum.Comment: 34 pages, 14 figures, 4 table

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

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    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

    Brane-Localized Goldstone Fermions in Bulk Supergravity

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    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

    Multiple Scattering Theory for Slow Neutrons (from thermal to ultracold)

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    The general theory of neutron scattering is presented, valid for the whole domain of slow neutrons from thermal to ultracold. Particular attention is given to multiple scattering which is the dominant process for ultracold neutrons (UCN). For thermal and cold neutrons, when the multiple scattering in the target can be neglected, the cross section is reduced to the known value. A new expression for inelastic scattering cross section for UCN is proposed. Dynamical processes in the target are taken into account and their influence on inelastic scattering of UCN is analyzed.Comment: 28 pages, latex, 2 Postscript figures, submitted to the European Physical Journal

    W+2jets production at Tevatron -- VECBOS and CompHEP comparison

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    Results of calculation of all subprocesses in proton-antiproton collisions which contribute to the W+2jets final state are presented at Tevatron energy. The calculation has been carried out by means of the CompHEP software package. A detail comparison with VECBOS generator results for cross sections and various distributions shows an agreement at the level of Monte-Carlo accuracy. Therefore the additional independent check of VECBOS generator has been done. In complement to the VECBOS generator a new generator based on CompHEP allows to study individual subprocesses like WbbˉWb\bar{b} or WccˉWc\bar{c}. The last point is important, for instance, for study WbbˉWb\bar{b} part of the background for single top or Standard Model Higgs signal at Tevatron.Comment: 8 pages including 4 figures as a gzipped postscript fil