31 research outputs found

    A 125 GeV Higgs and its di-photon signal in different SUSY models: a mini review

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    In this note we briefly review our recent studies on a 125 GeV Higgs and its di-photon signal rate in different low energy supersymmetric models, namely the minimal supersymmetric standard model (MSSM), the next-to-minimal supersymmetric standard model (NMSSM), the nearly minimal supersymmetric standard model (nMSSM) and the constrained MSSM. Our conclusion is: (i) In the allowed parameter space the SM-like Higgs boson can easily be 125 GeV in the MSSM, NMSSM and nMSSM, while it is hard to realize in the constrained MSSM; (ii) The di-photon Higgs signal rate in the nMSSM and constrained MSSM is suppressed relative to the prediction of the SM, while the signal rate can be enhanced in the MSSM and NMSSM; (iii) The NMSSM may allow for a lighter top-squark than the MSSM, which can thus ameliorate the fine-tuning problem.Comment: 16 pages, 8 figures,version in Advances in High Energy Physic

    Top quark forward-backward asymmetry at the Tevatron: a comparative study in different new physics models

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    The top quark forward-backward asymmetry A_{FB}^t measured at the Tevatron is above the Standard Model prediction by more than 2-sigma deviation, which might be a harbinger for new physics. In this work we examine the contribution to A_{FB}^t in two different new physics models: one is the minimal supersymmetric model without R-parity (RPV-MSSM) which contributes to A_{FB}^t via sparticle-mediated t-channel process d d_bar-> t t_bar; the other is the third-generation enhanced left-right model (LR model) which contributes to A_{FB}^t via Z'-mediated t-channel or s-channel processes. We find that in the parameter space allowed by the tt_bar production rate and the tt_bar invariant mass distribution at the Tevatron, the LR model can enhance A_{FB}^t to within the 2-sigma region of the Tevatron data for the major part of the parameter space, and in optimal case A_{FB}^t can reach 12% which is slightly below the 1-sigma lower bound. For the RPV-MSSM, only in a narrow part of the parameter space can the \lambda'' couplings enhance A_{FB}^t to within the 2-sigma region while the \lambda' couplings just produce negative contributions to worsen the fit.Comment: Version in PRD (RPV-MSSM lambda" effects added

    Pair production of 125 GeV Higgs boson in the SM extension with color-octet scalars at the LHC

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    Although the Higgs boson mass and single production rate have been determined more or less precisely, its other properties may deviate significantly from its predictions in the standard model (SM) due to the uncertainty of Higgs data. In this work we study the Higgs pair production at the LHC in the Manohar-Wise model, which extends the SM by one family of color-octet and isospin-doublet scalars. We first scanned over the parameter space of the Manohar-Wise model considering exprimental constraints and performed fits in the model to the latest Higgs data by using the ATLAS and CMS data separately. Then we calculated the Higgs pair production rate and investigated the potential of its discovery at the LHC14. We conclude that: (i) Under current constrains including Higgs data after Run I of the LHC, the cross section of Higgs pair production in the Manohar-Wise model can be enhanced up to even 10310^3 times prediction in the SM. (ii) Moreover, the sizable enhancement comes from the contributions of the CP-odd color-octet scalar SIAS^A_I. For lighter scalar SIAS^A_I and larger values of λI|\lambda_I|, the cross section of Higgs pair production can be much larger. (iii) After running again of LHC at 14 TeV, most of the parameter spaces in the Manohar-Wise model can be test. For an integrated luminosity of 100 fb1^{-1} at the LHC14, when the normalized ratio R=10R=10, the process of Higgs pair production can be detected.Comment: 13 pages, 4 figure

    Pair Production of a 125 GeV Higgs Boson in MSSM and NMSSM at the LHC

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    In light of the recent LHC Higgs search data, we investigate the pair production of a SM-like Higgs boson around 125 GeV in the MSSM and NMSSM. We first scan the parameter space of each model by considering various experimental constraints, and then calculate the Higgs pair production rate in the allowed parameter space. We find that in most cases the dominant contribution to the Higgs pair production comes from the gluon fusion process and the production rate can be greatly enhanced, maximally 10 times larger than the SM prediction (even for a TeV-scale stop the production rate can still be enhanced by a factor of 1.3). We also calculate the chi-square value with the current Higgs data and find that in the most favored parameter region the production rate is enhanced by a factor of 1.45 in the MSSM, while in the NMSSM the production rate can be enhanced or suppressed (\sigma_{SUSY}/\sigma_{SM} varies from 0.7 to 2.4).Comment: 15 pages, 5 figure

    Properties of Heavy Higgs Bosons and Dark Matter under Current Experimental Limits in the μ\muNMSSM

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    Searches for new particles beyond the Standard Model (SM) are an important task for the Large Hadron Collider (LHC). In this paper, we investigate the properties of the heavy non-SM Higgs bosons in the μ\mu-term extended Next-to-Minimal Supersymmetric Standard Model (μ\muNMSSM). We scan the parameter space of the μ\muNMSSM considering the basic constraints from Higgs data, dark matter (DM) relic density, and LHC searches for sparticles. And we also consider the constraints from the LZ2022 experiment and the muon anomaly constraint at 2σ\sigma level. We find that the LZ2022 experiment has a strict constraint on the parameter space of the μ\muNMSSM, and the limits from the DM-nucleon spin-independent (SI) and spin-dependent (SD) cross-sections are complementary. Then we discuss the exotic decay modes of heavy Higgs bosons decaying into SM-like Higgs boson. We find that for doublet-dominated Higgs h3h_3 and A2A_2, the main exotic decay channels are h3ZA1h_3\rightarrow Z A_1, h3h1h2h_3\rightarrow h_1 h_2, A2A1h1A_2\rightarrow A_1 h_1 and A2Zh2A_2\rightarrow Z h_2, and the branching ratio can reach to about 23%\%, 10%\%, 35%\% and 10%\% respectively. At the 13 TeV LHC, the production cross-section of ggFh3h1h2ggF\rightarrow h_3\rightarrow h_1 h_2 and ggFA2A1h1ggF\rightarrow A_2\rightarrow A_1 h_1 can reach to about 101110^{-11}pb and 101010^{-10}pb, respectively
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