A Self Interacting Dark Matter Model Under New U(1) Gauge Field

We first review the current status of the field of dark matter(DM) in chapter 2, including astrophysical evidences, DM types, DM models and DM detection.In chapter 3 we present some astronomical observations which are inconsistent with NFW density profile. This motivates self interacting dark matter(SIDM) model. By using N-body simulation, M. Rocha et al. found that SIDM with the ratio of cross section to mass σ/m= 0.1cm2/g may explain the astronomical observations from dwarfs to galaxy clusters scale. Here, σ/m(?) 0 indicates that there is self interacting between dark matter. In chapter 4 we discuss SIDM under new U(1) gauge field. Firstly, we present WIMPless model with hidden charged sector, where only the third-generation hidden right-handed stau X=~ThR is assumed to be the DM candidate. The allowed range of mx and gx is obtained by considering the constraint of DM relic density, including Sommerfeld enhancement and bound state’s effect. In addition, we present SIDM minimal model under new U(1) gauge field(X and dark photon) to discuss relic density and galactic dynamics. In this model the DM mass mx is around TeV and fine-structure constant αD(?) 10-3. One may add another light fermion C based on minimal model to construct dissipative dynamics between C and X. In this case, the arrowed ranges of mX,mC and αD are obtained by considering relic density and cooling based on Compton scattering and Bremsstrahlung. Finally, SIDM effect on solar system is briefly discussed.