21,343 research outputs found

    The Discovery of the Higgs Boson with the CMS Detector and its Implications for Supersymmetry and Cosmology

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    The discovery of the long awaited Higgs boson is described using data from the CMS detector at the LHC. In the SM the masses of fermions and the heavy gauge bosons are generated by the interactions with the Higgs field, so all couplings are related to the observed masses. Indeed, all observed couplings are consistent with the predictions from the Higgs mechanism, both to vector bosons and fermions implying that masses are indeed consistent of being generated by the interactions with the Higgs field. However, on a cosmological scale the mass of the universe seems not to be related to the Higgs field: the baryonic mass originates from the binding energy of the quarks inside the nuclei and dark matter is not even predicted in the SM, so the origin of its mass is unknown. The dominant energy component in the universe, the dark energy, yields an accelerated expansion of the universe, so its repulsive gravity most likely originates from a kind of vacuum energy. The Higgs field would be the prime candidate for this, if the energy density would not be many orders of magnitude too high, as will be calculated. The Higgs mass is found to be 125.7±\pm0.3(stat.)±\pm0.3(syst.) GeV, which is below 130 GeV, i.e. in the range predicted by supersymmetry. This may be the strongest hint for supersymmetry in spite of the fact that the predicted supersymmetric particles have not been discovered so far.Comment: 26 pages, Conference Proceedings Time and Matter (TAM2013), Venice, Feb. 201

    Dark conductivity of CdS as a function of S-vapor pressure during heat treatment between 500 deg C and 700 deg C

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    Cadmium sulfide dark conductivity as function of sulfur vapor pressure during heat treatment between 500 and 700 deg

    Assessment of the international workshop on CdS solar cells

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    General problems relating to the basic understanding of CdS/Cu2S solar cell operation, to material aspects of the cell and to manufacturing methods and cell engineering are discussed

    X-ray and electron damage, and photochemical reactions in CdS single crystals and layers, and annealing of these defects Final report

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    X-ray and electron damage and photochemical reactions in CdS single crystals and layers with defect annealin

    An effective scanning method of the NMSSM parameter space

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    The next-to-minimal supersymmetric standard model (NMSSM) naturally provides a 125 GeV Higgs boson without the need for large loop corrections from multi-TeV stop quarks. Furthermore, the NMSSM provides an electroweak scale dark matter candidate consistent with all experimental data, like relic density and non-observation of direct dark matter signals with the present experimental sensitivity. However, more free parameters are introduced in the NMSSM, which are strongly correlated. A simple parameter scan without knowing the correlation matrix is not efficient and can miss significant regions of the parameter space. We introduce a new technique to sample the NMSSM parameter space, which takes into account the correlations. For this we project the 7D NMSSM parameter space onto the 3D Higgs boson mass parameter space. The reduced dimensionality allows for a non-random sampling and therefore a complete coverage of the allowed NMSSM parameters. In addition, the parameter correlations and possible deviations of the signal strengths of the observed 125 Higgs boson from the SM values are easily predicted.Comment: 15 pages, 5 figure

    Spontaneous electro-weak symmetry breaking and cold dark matter

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    In the standard model, the weak gauge bosons and fermions obtain mass after spontaneous electro-weak symmetry breaking, which is realized through one fundamental scalar field, namely Higgs field. In this paper we study the simplest scalar cold dark matter model in which the scalar cold dark matter also obtains mass through interaction with the weak-doublet Higgs field, the same way as those of weak gauge bosons and fermions. Our study shows that the correct cold dark matter relic abundance within 3σ3\sigma uncertainty (0.093<Ωdmh2<0.129 0.093 < \Omega_{dm} h^2 < 0.129 ) and experimentally allowed Higgs boson mass (114.4≤mh≤208114.4 \le m_h \le 208 GeV) constrain the scalar dark matter mass within 48≤mS≤7848 \le m_S \le 78 GeV. This result is in excellent agreement with that of W. de Boer et.al. (50∼10050 \sim 100 GeV). Such kind of dark matter annihilation can account for the observed gamma rays excess (10σ10\sigma) at EGRET for energies above 1 GeV in comparison with the expectations from conventional Galactic models. We also investigate other phenomenological consequences of this model. For example, the Higgs boson decays dominantly into scalar cold dark matter if its mass lies within 48∼6448 \sim 64 GeV.Comment: 4 Revtex4 pages, refs adde
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