Search for Contact Interactions in Dilepton Final State in the CMS Experiment: Generator-Level Studies

A set of contact interaction (CI) Monte Carlo events, for which Standard Model Drell­-Yan events are background, are generated using a leading-order parton-shower generator, Pythia8. We consider three isoscalar models with three different helicity structures, left­-left (LL), left­-right/right­-left (LR), and right­right (RR), each with destructive and constructive interference. . For each of these models, 150,000 events are generated for analysis of CI interactions in the Compact Muon Solenoid (CMS) experiment at the Large Hadron Collider (LHC) with a centre of mass energy of 13 TeV. This study is a generator level study, and detector effects are accounted for by application of kinematic cuts on the generator-level quantities rather than application of a detailed detector simulation package (e.g. GEANT). Distributions of dilepton invariant mass, Collins­-Soper angle, and the forward­-backward asymmetry are compared with those arising from pure Drell-Yan events.