Compositeness Search with Di-muons in CMS

Virtual effects from a generic description of physics beyond the Standard Model in terms of contact interactions will modify the observed cross sections for easy to detect final states like lepton-pairs, and can be used to probe scales much higher than the center-of-mass energy of the partons initiating the interactions. In this contribution the sensitivity reach of the Compact Muon Solenoid experiment at the Large Hadron Collider to contact interactions in the Drell-Yan di-muon channel is investigated. The double-ratio method for studying the steeply falling Drell-Yan mass spectrum is developed and shown to deal successfully, and with reduced systematic uncertainties, with the background normalization in a compositeness search. Experimental aspects of the measurements, systematic error effects and the evolution of the search reach with accumulated luminosity are considered.