  The Standard Model of particle physics is extremely well tested and yet is
not believed to be a theory of everything. Many extensions of the Standard
Model predict the existence of new particles. The Large Hadron Collider (LHC)
is a high energy proton-proton collider which may be able to produce such
particles. In this work strategies have been developed to search for new
physics by identifying high energy electrons produced by the decay of W boson
using 2.8 pb-1 of real data. The electron identification for CMS has been
presented. Simple cut based selections and a complete set of variables to
distinguish between real electrons and background electrons are described. The
detection of electrons is of particular importance at LHC as these particles
intervene in the flagship H -> ZZ* -> 4e and H -> WW* -> 2e2v channels for the
search of the Standard Model (SM) Higgs. Electrons are also important in many
SUSY scenarios as produced in the leptonic decays of charginos and neutralinos.
Electrons also appears in searches for TeV resonances that may come from new
symmetries or as consequences of scenarios involving extra spatial dimensions.
Last but not the least, electrons appear in the final state of many Standard
Model processes involving top quarks or electroweak bosons, that constitute
backgrounds to new signals or are intended to be used as calibration processes.
In second part of my thesis background sources for electrons coming from W
bosons have been studied. Electron identification variables are plotted in
different regions of background, to study the background as deeply as possible.
This work has been done for the first time using LHC's real data.
