A multi-lepton search for new physics in $\mathbf{35~pb^{-1}}$ proton-proton collisions at the LHC with a center mass energy of $\mathbf{\sqrt{s}=7~TeV}$ using the CMS detector

This thesis describes a model independent search for new physics with a decay signature of three or more leptons and missing transverse energy in $35~\mathrm{pb^{-1}}$ of proton-proton collisions at the LHC at a center mass energy $\sqrt{s}=7$~TeV using the CMS detector. Standard Model backgrounds are predicted using both simulations and collision data. The observed events are consistent with the Standard Model predictions. The results are interpreted using various super-symmetry models: gravity mediated breaking, the gauge mediated breaking with slepton co-NLSP, and leptonic R-parity violating.