This Ph.D. thesis is a search for physics beyond the standard model (SM) of particle physics
which successfully describes the interactions and properties of all known elementary particles.
However no particle exists in the SM that can account for the dark matter which makes up
about one quarter of the energy-mass content of the universe. Understanding the nature of dark
matter is one goal of the CERN Large Hadron Collider (LHC). The extension of the SM with
supersymmetry (SUSY) is considered a promising possibilities to explain dark matter.The
nominated thesis describes a search for SUSY using data collected by the CMS experiment at the
LHC. It utilizes a final state consisting of a photon a lepton and a large momentum imbalance
probing a class of SUSY models that has not yet been studied extensively. The thesis stands out
not only due to its content that is explained with clarity but also because the author
performed more or less all aspects of the thesis analysis by himself from data skimming to
limit calculations which is extremely rare especially nowadays in the large LHC
collaborations.
