Tests Of New Physics Beyond The Standard Model In Astrophysical Observations And Colliders

This thesis is devoted to the tests of new physics beyond the Standard Model in astro-physical observations and colliders. Motived by observations of the electron and positron excesses from the PALEMA and Fermi-LAT Collaborations, we discuss a decaying dark matter model to interpret them in the framework of supersymmetric SU(5) grand unifica-tion theory. We study the corresponding gamma-ray signals from this model in the region0°≤l≤360°,10°≤|b|≤20°and in the clusters of galaxies, to be compared to the recent observations. We then provide a novel method to determine dark matter induced electron/positron spectrum at the source from experimental measurements at the earth, without ref-erence to specific particle physics models. For decaying dark matter scenario, we predict the flux of gamma rays via inverse Compton scattering in the Fornax cluster, which turns out to be disagreement with recent Fermi-LAT measurements. The third topic of this paper is about phenomenologies of the dielectron channel and diphoton channel in the two Higgs doublet models. At last we study the nonlinear realization of supersymmetry. We discuss a systematic avenue to construct nonlinear supersymmetric theories from linear ones. The constrained superfield formalism discovered by Komargodski and Seiberg can be reinter-preted in the language of the standard realization of nonlinear supersymmetry via a simple route. We also prove the equivalence among various Akulov-Volkov actions.