Studies On Dark Matter Phenomenology

The standard model（SM）describing the elementary particles and their interactions is one the most important achievements of physics in the twentieth century.It can explain a wide variety of high energy physics experiments successfully.But the standard model is not complete on the other hand,such as it cannot provide a dark matter candidate.A large number of experiments show that dark matter is the main component of matter in the universe,which accounts for about a quarter of the total energy of the universe.Theorists put forward various new physical models to explain dark matter in particle physics,such as supersymmetry,extra dimension and axion model.We will make phenomenological study on two simple standard model expansion theories in this paper.First,the Higgs-portal scalar dark matter model（HSDM）is the simplest extension of the standard model.We add a singlet scalar s to the standard model,and s is coupled with the SM Higgs only.With theZ₂ parity,which makes the dark matter s stable,the parameters of HSDM are the mass of dark matterm_s and the s-Higgs coupling?.HSDM is sensitive to the experiment because of the few free model parameters.We consider two cases where s are real scalar and complex scalar in this work,and obtain the corresponding parameter space under the relic density of dark matter given by Planck satellite.Combine the constraints from the DM direct detection experiments LUX2016 and XENON1T and Higgs invisible decay and gamma ray spectra given by Fermi-LAT and H.E.S.S.,we make some restrictions on the parameter space of the model.The resonant mass region of real scalar and complex scalar dark matter is restricted to 54.9—62.3GeV and 53.8—62.2GeV,and the large mass region is excluded until 834GeV and 3473GeV for real scalar and complex scalar dark matter respectively.Then,neutral Majorana dark matter is another extension of the standard model.In this work,we study Majorana dark matter from the viewpoint of effective field theory.The neutral Majorana fermion is added to SM,and connects with SM by coupling with Z boson and Higgs.The number of model parameters is reduced to three,which are the mass of dark matter and the two coupling constants.We give the analytical results for dark matter annihilation into the SM background,and find out the parameter space which is survived in the relic density,LUX2016,PandaX and XENON1T limits in a model-independent way.For illustration,the model-independent result is applied to the decoupled singlet-doublet model and minimum supersymmtric standard model（MSSM）.