Phenomenological Study Of Dark Matter At High Energy Particle Collider

This paper focuses on the detection of dark matter in the particle collider.Astronomical observation results show that there is a large amount of dark matter in the universe.According to WMAP observations,dark matter accounts for about 23.5%of the total energy of the universe.Since the concept of dark matter was emerged,in order to explain some experimental phenomena in astronomical observation and particle physics,many theories about dark matter beyond the standard model have been put forward.In addition,the direct detection,indirect detection and collider detection experiments of dark matter give corresponding detection limits to these theoretical models.The collider Dark Matter(DM)searches is an important and powerful way to explore new physics beyond Standard Model(SM),which allows us to impose strong constraints on the interactions between DM and SM particles through transverse missing energy recoiled by energetic visible particles.In the chapter 3,we investigate the constraints on effective operators involving DM and electroweak gauge bosons at the future electron-proton colliders,including the Large Hadron Electron Collider(LHeC)and Future Circular Collider in electron-proton mode(FCC-ep).We consider the dimension-6(7)DM-diboson effective operators for scalar(Dirac fermion)DM,which is characterized by the effective energy scale? and the Wilson coefficients CB(?),Cw(?).Using ET+e-j signal channel,we present the constraints on ? as a function of DM mass with different parameter choices of CB(?)and Cw(?).The contour distributions of A in the CB(?)-Cw(?)plane and its relation with ?? and ZZ production modes is also discussed.We propose to search the monophoton events at the BES? detector and future Super Tau Charm Factory to probe the sub-GeV dark photon decay into lighter dark matter.We compute the cross section due to the dark photon associated a standard model photon production,and study the corresponding standard model irreducible/reducible backgrounds.By using the data about 14 fb-1 collected at the BES? detector since 2012,we derive new leading limits of the mixing strength ??(1.1-1.6)×10-4,in the mass range of 0.04 GeV?mA'?3 GeV.With 30 ab-1 data,STCF running at(?)=2 GeV,can probe ? down to 5.1 × 10-6 when mA'=1 GeV.For models of scalar and fermionic light thermal dark matter production via dark photon,we present the constrains on the dimensionless dark matter parameter y=?2?D(mx//mA')4 as function of the DM mass m? at BES? and future STCF,conventionally assuming the dark coupling constant ?D=0.5 and mA'=3 mx.We find that BES? can exclude model of scalar,Majorana,and pseudo-Dirac(with a small splitting)DM for the mass region 0.03?1 GeV,0.04?1 GeV and 0.4?1 GeV respectively.For values ?D?0.005,combining the results from 2 GeV STCF with 30 ab-1 data and BaBar,one can exclude the above three DM models in the mass region 0.001 GeV?m??1 GeV.