In the first part of this dissertation a search for large extra dimensions in the context of the ADD model in di-electron final state is investigated. This search is performed with data collected by the CMS detector in proton-proton collisions at the Large Hadron Collider. The analysis is based on data consist of an integrated luminosity corresponding to in the center-of-mass energy of 7 TeV and corresponding data at the center-of-mass energy of 8 TeV. The signal of the model can appear in the processes like Drell-Yan but with the exchange of graviton instead of photon or Z boson and increase the production cross section of the di-electrons in the final state by considering the extra dimension contribution and interference term between SM and extra dimensions. This increase in the cross section can be observed as an enhancement in the tail of the invariant mass of di-electron. Several sources of the SM backgrounds exist. The MC simulation and data driven methods are used to estimate them precisely. Finally, the expected background is compared with the observed data taking to account the different sources of systematic and statistical uncertainties. No deviation from the SM model prediction is observed. Therefore, real data is used to put upper limit on the parameters of the model. In the second part of thesis, the anomalous interactions of the top quark are studied. At the first step, flavor changing neutral current interactions in the associated tW channel of single top is explored. The symmetry in the production of the top and anti-top is vanished in the presence of the FCNC interactions. Such an asymmetry provides an interesting tool to put the limit on the anomalous couplings. In another part of this thesis, the angular correlation in the decay of the top quark in the presence of models beyond standard model is investigated. In this work the stability of this correlation in the presence of beyond standard models such as two higgs doublet model and top color assisted Technicolor is examined.