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 3σ uncertainty (0.093 < Ωdm h² < 0.129) and experimentally allowed Higgs boson mass (114.4 ≤ mₕ ≤ 208 GeV) constrain the scalar dark matter mass within 48 ≤ mₛ ≤ 78 GeV. This result is in excellent agreement with that of W. de Boer et.al. (50 100 GeV). Such kind of dark matter annihilation can account for the observed gamma rays excess (10σ) 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 64 GeV.