Relic Abundance of Scalar Dark Matter

The nature of dark matter is one of the great unsolved questions in particle physics and cosmology. Infact, the hypothesis of dark matter is strongly supported by the galaxy rotation curve, gravitational lensing and large scale structure of the universe. However, there is no candidate of dark matter in the standard model of particle physics. Different extensions of the standard model provide candidates of dark matter. This thesis concerns with two models, Scalar Singlet model and Inert Higgs Doublet Model and calculating the relic abundance of dark matter in both models, to further check their suitability as a candidate of dark matter. WMAP and PLANCK measurements of anisotropies- the Cosmic Microwave Background precisely measure the relic abundance of dark matter. We compare our theoretical estimated value of the relic abundance of dark matter with the WMAP and PLANCK value of relic abundance and find the relevant constraints on the model parameters