分类： 物理学 >> 基本粒子与场物理学 提交时间： 2016-05-15
摘要： As discussed recently by Hooper and Tait, the singlino-like dark matter in the Minimal Supersymmetric Standard Model (MSSM) extended by a singlet Higgs superfield can give a perfect explanation for both the relic density and the Pamela result through the Sommerfeld-enhanced annihilation into singlet Higgs bosons (a or h followed by h -> aa) with a being light enough to decay dominantly to muons or electrons. In this work we analyze the parameter space required by such a dark matter explanation and also consider the constraints from the LEP experiments. We find that although the light singlet Higgs bosons have small mixings with the Higgs doublets in the allowed parameter space, their couplings with the SM-like Higgs boson h(SM) (the lightest doublet-dominant Higgs boson) can be enhanced by the soft parameter A(kappa) and, in order to meet the stringent LEP constraints, the h(SM) tends to decay into the singlet Higgs pairs a a or hh instead of b (b) over bar. So the h(SM) produced at the LHC will give a multi-muon signal, h(SM) -> aa -> 4 mu or h(SM) -> hh -> 4a -> 8 mu.
分类： 物理学 >> 基本粒子与场物理学 提交时间： 2016-05-15
摘要： We perform a comparative study of the neutralino dark matter scattering on nucleon in three popular supersymmetric models: the minimal (MSSM), the next-to-minimal (NMSSM) and the nearly minimal (nMSSM). First, we give the predictions of the elastic cross section by scanning over the parameter space allowed by various direct and indirect constraints, which are from the measurement of the cosmic dark matter relic density, the collider search for Higgs boson and sparticles, the precision electroweak measurements and the muon anomalous magnetic moment. Then we demonstrate the property of the allowed parameter space with/without the new limits from CDMS II. We obtain the following observations: (i) For each model the new CDMS limits can exclude a large part of the parameter space allowed by current collider constraints; (ii) The property of the allowed parameter space is similar for MSSM and NMSSM, but quite different for nMSSM; (iii) For each model the future SuperCDMS can cover most of the allowed parameter space given that all soft breaking parameters are below 1 TeV.
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