Thesis (M.Sc.) - Cairo University - Faculty of Science - Department of Physics

Search for Dark Matter Candidates becomes one of the most important proposals in High Energy Physics researches, that can be done based on the detection of missing energy at the particle colliders. In the other hand, a new gauge boson denoted by Z{u2032} is predicted by some of Beyond the Standard Model BSM theories.This thesis present a search for the process of the production of DM particles alongside with the new gauge boson (Z{u2032}), within events containing dimuon pairs that yield from the decay of Z{u2032} boson and a large missing transverse momentum attributed to the production of dark sector particles, the process obeys a model called Mono{u2010}Z{u2032} model. Two scenarios are used in the interpretation of the results, the Dark Higgs scenario as a simplified approach of the model and the Effective Field Theory EFT approach of the model. The signals of these scenario are generated using Madgraph and simulated for the CMS apparatus using the standard CMSSW. We have analyzed a data sample recorded by the CMS detector in 2012 during the LHC run{u2010}I, for pp collision at a c.m.e of 8 TeV and corresponding to a total integrated luminosity of 11.6 fb⁻¹. the sensitivity of the CMS to the model for the full run{u2010}I data (corresponding to a total integrated luminosity of 19.7 fb⁻¹) is also investigated.The Standard Model SM expected backgrounds are built using the open MC samples generated by the CMS collaboration, the total uncertainty related to the estimation of the SM background is considered during the interpretation of the results. Limits on the mass of the new Z{u2032} boson, the mass of the dark matter particle { and the cut off scale of the EFT scenario , have been set at 95% Confidence Level CL

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