1,287 research outputs found

    An update of the constraints on the phenomenological MSSM from the new LHC Higgs results

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    Updated results on the search of Higgs bosons at the LHC with up to 17/fb of data have just been presented by the ATLAS and CMS collaborations. New constraints are provided by the LHCb and XENON experiments with the observation of the rare decay B_s -> mu+mu- and new limits on dark matter direct detection. In this paper, we update and extend the results on the implications of these data on the phenomenological Minimal Supersymmetric extension of the Standard Model (pMSSM) by using high statistics, flat scans of its 19 parameters. The new LHC data on bb and tau tau decays of the lightest Higgs state and the new CMS limits from the tau tau searches for the heavier Higgs states set stronger constraints on the pMSSM parameter space.Comment: 14 pages, 8 figures. This update is based on results presented at HCP 2012 and the December 2012 CERN Council LHC Jamboree. It features larger scan statistics and additional plot

    Implications of LHC Higgs and SUSY searches for MSSM

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    The implications of the LHC SUSY searches as well as the discovery of a new bosonic state compatible with the lightest Higgs boson will be discussed in the context of constrained and general MSSM scenarios. Exploring the MSSM through the Higgs sector is an alternative and complementary path to direct searches, and tight constraints on the MSSM parameter space can be obtained.Comment: 7 pages, 5 figures, contribution to the ICHEP 2012 Conference proceedings, 4-11 July 2012, Melbourne, Australi

    The Search for Higgs particles at high-energy colliders: Past, Present and Future

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    I briefly review the Higgs sector in the Standard Model and its minimal Supersymmetric extension, the MSSM. After summarizing the properties of the Higgs bosons and the present experimental constraints, I will discuss the prospects for discovering these particle at the upgraded Tevatron, the LHC and a high-energy e+ee^+e^- linear collider. The possibility of studying the properties of the Higgs particles will be then summarized.Comment: 28 pages, latex, 15 figures, talk at WHEPP VII, Allahabad, Indi

    The Higgs sector of the phenomenological MSSM in the light of the Higgs boson discovery

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    The long awaited discovery of a new light scalar at the LHC opens up a new era of studies of the Higgs sector in the SM and its extensions. In this paper we discuss the consequences of the observation of a light Higgs boson with the mass and rates reported by the ATLAS and CMS collaborations on the parameter space of the phenomenological MSSM, including also the so far unsuccessful LHC searches for the heavier Higgs bosons and supersymmetric particle partners in missing transverse momentum as well as the constraints from B physics and dark matter. We explore the various regimes of the MSSM Higgs sector depending on the parameters MA and tan beta and show that only two of them are still allowed by all present experimental constraints: the decoupling regime where there is only one light and standard--like Higgs boson and the supersymmetric regime in which there are light supersymmetric particle partners affecting the decay properties of the Higgs boson, in particular its di-photon and invisible decays.Comment: 21 pages, 9 figures v2 - Discussion of the impact of LHC data extended, scan statistics increased, a few figures added and typos correcte

    Physics at \ggam and \egam colliders

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    I discuss, what really new could give Photon Colliders (γγ\gamma\gamma and eγe\gamma) after LHC and \epe Linear Collider operations.Comment: 7pages,LaTEX, To be published in proceedings "PHOTON99". The forgotten title, author and abstract are added in the tex

    QCD Corrections to Production of Higgs Pseudoscalars

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    Models of electroweak symmetry breaking with more than a single doublet of Higgs scalars contain a neutral pseudoscalar boson. The production of such a pseudoscalar in hadron collisions proceeds primarily via gluon fusion through a top-quark loop (except for those models in which the pseudoscalar coupling to bottom quarks is strongly enhanced). We compute the QCD corrections to this process in the heavy-quark limit, using an effective Lagrangian derived from the axial anomaly.Comment: 9 pages, (BNL number added, 1 typo corrected, PHYZZX format, 4 figures not included, available on request), BNL-4906

    The Higgs boson in the MSSM in light of the LHC

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    We investigate the expectations for the light Higgs signal in the MSSM in different search channels at the LHC. After taking into account dark matter and flavor constraints in the MSSM with eleven free parameters, we show that the light Higgs signal in the gammaγgamma\gamma channel is expected to be at most at the level of the SM Higgs, while the hbbˉh\rightarrow b\bar{b} from W fusion and/or the hττˉh \rightarrow\tau\bar\tau can be enhanced. For the main discovery mode, we show that a strong suppression of the signal occurs in two different cases: low MAM_A or large invisible width. A more modest suppression is associated with the effect of light supersymmetric particles. Looking for such modification of the Higgs properties and searching for supersymmetric partners and pseudoscalar Higgs offer two complementary probes of supersymmetry.Comment: 19 pages, 8 figure

    SUSY Higgs at the LHC: Effects of light charginos and neutralinos

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    In view of the latest LEP data we consider the effects of charginos and neutralinos on the two-photon and bbbar signatures of the Higgs at the LHC. Assuming the usual GUT inspired relation between M_1 and M_2 we show that there are only small regions with moderate tanbeta and large stop mixings that may be dangerous. Pathological models not excluded by LEP which have degeneracy between the sneutrino and the chargino are however a real danger because of large branching fraction of the Higgs into invisibles. We have also studied models where the gaugino masses are not unified at the GUT scale. We take M_1=M_2/10 as an example where large reductions in the signal at the LHC can occur. However we argue that such models with a very light neutralino LSP may give a too large relic density unless the sleptons are light. We then combine this cosmological constraint with neutralino production with light sfermions to further reduce the parameter space that precludes observability of the Higgs at the LHC. We still find regions of parameter space where the drops in the usual Higgs signals at the LHC can be drastic. Nonetheless, in such scenarios where Higgs may escape detection we show that one should be able to produce all charginos and neutralinos. Although the heavier of these could cascade into the Higgs, the rates are not too high and the Higgs may not always be recovered this way.Comment: 37 pages, 17 figures, Latex file, Paper with high resolution figures can be found at http://wwwlapp.in2p3.fr/web/lapp/preplapp/psth/LAPTH774.ps.g

    Refined gluino and squark pole masses beyond leading order

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    The physical pole and running masses of squarks and gluinos have recently been related at two-loop order in a mass-independent renormalization scheme. I propose a general method for improvement of such formulas, and argue that better accuracy results. The improved version gives an imaginary part of the pole mass that agrees exactly with the direct calculation of the physical width at next-to-leading order. I also find the leading three-loop contributions to the gluino pole mass in the case that squarks are heavier, using effective field theory and renormalization group methods. The efficacy of these improvements for the gluino and squarks is illustrated with numerical examples. Some necessary three-loop results for gauge coupling and fermion mass beta functions and pole masses in theories with more than one type of fermion representation, which are not directly accessible from the published literature, are presented in an Appendix.Comment: 14 pages. v2: typos in equations (A.11), (A.17), and (A.18) fixe

    Higgs Physics at Future Colliders: recent theoretical developments

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    I review the physics of the Higgs sector in the Standard Model and its minimal supersymmetric extension, the MSSM. I will discuss the prospects for discovering the Higgs particles at the upgraded Tevatron, at the Large Hadron Collider, and at a future high--energy e+ee^+e^- linear collider with centre--of--mass energy in the 350--800 GeV range, as well as the possibilities for studying their fundamental properties. Some emphasis will be put on the theoretical developments which occurred in the last two years.Comment: 20 pages, latex, 12 figures. Talk given at PASCOS 2003 (Bombay, India
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