3,361 research outputs found

    CP Violation in γγt tˉ\gamma \gamma \to t~\bar{t} within the Minimal Supersymmetric Standard Model

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    The complete analysis of the CP violation in the process γγttˉ\gamma \gamma \to t \bar{t} in frame of the Minimal Supersymmetric Model(MSSM) is presented. The CP-odd observables for describing the CP violating effects in polarized and unpolarized photon collisions, are calculated. We investigate the possible CP violation sources induced by the complex soft breaking parameters and study the CP violating effects contributed by gluino, neutralino and chargino sectors appearing in the loop diagrams. We find that it is possible to observe the CP violation effects in top quark pair production via polarized and unpolarized photon fusions by using optimal observables and favorable parameters.Comment: 15 pages, LaTex, including 14 figures in eps file

    CP violation in associated charged Higgs boson production with a single top at the LHC

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    We explore the CP violation in the charged Higgs production associated with a top quark at the LHC in the MSSM. The supersymmetric phases of gaugino masses and trilinear AA terms lead to a CP violating asymmetry of the cross section in the ppgbtH± p p \to g b \to t H^\pm process through loop corrections to the tbH±tbH^\pm vertex. We find that a CP violation more than 10 % is possible if the charged Higgs boson is heavy enough.Comment: 8 pages including 5 eps figures, JHEP, corrections mad

    Top quark pair production via polarized and unpolarized photons in Supersymmetric QCD

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    QCD corrections to top quark pair production via fusion of both polarized and unpolarized photons are calculated in Supersymmetric Model. The corrections are found to be sizable. The dependence of the corrections on the masses of the supersymmetric particles is also investigated. Furthermore, we studied CP asymmetry effects arising from the complex couplings in the MSSM. The CP violating parameter can reach 10210^{-2} for favorable parameter values.Comment: 26 pages, LaTex, including 12 figures in 12 eps files. submitted to Phys. Rev.

    SUSY-QCD decoupling properties in H+ -> t \bar b decay

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    The SUSY-QCD radiative corrections to the \Gamma (H+ -> t \bar b) partial decay width are analyzed within the Minimal Supersymmetric Standard Model at the one-loop level, {\mathcal O}(\alpha_s), and in the decoupling limit. We present the analytical expressions of these corrections in the large SUSY masses limit and study the decoupling behaviour of these corrections in various limiting cases. We find that if the SUSY mass parameters are large and of the same order, the one loop SUSY-QCD corrections {\it do not decouple}. The non-decoupling contribution is enhanced by \tan \beta and therefore large corrections are expected in the large \tan \beta limit. In contrast, we also find that the SUSY-QCD corrections decouple if the masses of either the squarks or the gluinos are separately taken large.Comment: LaTeX, 33 pages, 7 figure included. Uses cite.st

    Resolved Photon Processes

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    We review the present level of knowledge of the hadronic structure of the photon, as revealed in interactions involving quarks and gluons ``in" the photon. The concept of photon structure functions is introduced in the description of deep--inelastic eγe \gamma scattering, and existing parametrizations of the parton densities in the photon are reviewed. We then turn to hard \gamp\ and \gaga\ collisions, where we treat the production of jets, heavy quarks, hard (direct) photons, \jpsi\ mesons, and lepton pairs. We also comment on issues that go beyond perturbation theory, including recent attempts at a comprehensive description of both hard and soft \gamp\ and \gaga\ interactions. We conclude with a list of open problems.Comment: LaTeX with equation.sty, 85 pages, 29 figures (not included). A complete PS file of the paper, including figures, can be obtained via anonymous ftp from ftp://phenom.physics.wisc.edu/pub/preprints/1995/madph-95-898.ps.

    The SUSY EW-like corrections to top pair production in photon-photon collisions

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    We studied the one-loop contributions of the gaugino-Higgsino-sector to the process of top-pair production via γγ\gamma \gamma fusion at NLC in frame of the Minimal Supersymmetric Model(MSSM). We find that the corrections to γγttˉ\gamma \gamma \to t\bar{t} and e+eγγttˉe^+ e^- \to \gamma \gamma \to t\bar{t} are found to be significant and can approach to a few percent and one percent, respectively. Furthermore, the dependences of the corrections on the supersymmetric parameters are also investigated. The corrections are not sensitive to MSU(2)M_{SU(2)} (or μ|\mu|) when MSU(2) >> μM_{SU(2)}~>>~|\mu| (or μ >> MSU(2)|\mu|~>>~M_{SU(2)}) and are weakly dependent on the tanβ\tan{\beta} with MQM_Q (or μ|\mu|) being large enough. But they are sensitive to the c.m.s. energy of the incoming photons.Comment: LaTex, 33 pages, 8 Eps figuer

    Charged Higgs- and R-Parity-Violating Slepton-Strahlung at Hadron Colliders

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    It is shown that the radiation of a charged Higgs boson off a third-generation quark (charged-Higgs-strahlung) provides an important channel for the discovery of the charged Higgs at hadron colliders. Equivalently, in supersymmetric models with explicit lepton-number (R-parity) violation, sleptons may also be produced in association with quarks (slepton-strahlung). Higgs- and slepton-strahlung production cross sections are given for both the Tevatron and the LHC. The LHC cross sections imply that heavy O{\cal{O}}(TeV) charged Higgs bosons can be produced via charged-Higgs-strahlung and that strahlung production of charged sleptons is possible even for small R-parity violating couplings. The possible discovery of sleptons through this channel offers a surprising handle on models of neutrino masses.Comment: 23 pages, LaTex + RevTex, 11 figures (included). Title modified. (Published version.

    A Recombinant Rift Valley Fever Virus Glycoprotein Subunit Vaccine Confers Full Protection against Rift Valley Fever Challenge in Sheep

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    Citation: Faburay, B., Wilson, W. C., Gaudreault, N. N., Davis, A. S., Shivanna, V., Bawa, B., . . . Richt, J. A. (2016). A Recombinant Rift Valley Fever Virus Glycoprotein Subunit Vaccine Confers Full Protection against Rift Valley Fever Challenge in Sheep. Scientific Reports, 6, 12. doi:10.1038/srep27719Rift Valley fever virus (RVFV) is a mosquito-borne zoonotic pathogen causing disease outbreaks in Africa and the Arabian Peninsula. The virus has great potential for transboundary spread due to the presence of competent vectors in non-endemic areas. There is currently no fully licensed vaccine suitable for use in livestock or humans outside endemic areas. Here we report the evaluation of the efficacy of a recombinant subunit vaccine based on the RVFV Gn and Gc glycoproteins. In a previous study, the vaccine elicited strong virus neutralizing antibody responses in sheep and was DIVA (differentiating naturally infected from vaccinated animals) compatible. In the current efficacy study, a group of sheep (n=5) was vaccinated subcutaneously with the glycoprotein-based subunit vaccine candidate and then subjected to heterologous challenge with the virulent Kenya-128B-15 RVFV strain. The vaccine elicited high virus neutralizing antibody titers and conferred complete protection in all vaccinated sheep, as evidenced by prevention of viremia, fever and absence of RVFV-associated histopathological lesions. We conclude that the subunit vaccine platform represents a promising strategy for the prevention and control of RVFV infections in susceptible hosts
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