SEARCH FOR BOOSTED SEMI-VISIBLE JETS IN ALL-HADRONIC FINAL STATES WITH THE CMS EXPERIMENT

Abstract

This dissertation presents a search for the dark sector beyond the standard model (BSM)to be carried out using the Compact Muon Solenoid (CMS) experiment of the Large Hadron Collider (LHC) at CERN. It is developed and evaluated in this work using simulated Monte Carlo data from CMS in preparation for searching the actual Run2 CMS data. The search is focused on the strongly coupled Hidden Valley models that couple with the standard model (SM) via a leptophobic (fully hadronic) Z′ mediator. The final state of resonant production consists of one large jet composed of both visible and invisible particles. This search focuses on the lower mediator mass range (mZ′ ≤ 550 GeV ) with the boosted topology that recoils against the initial state radiation (ISR) jet such that its decay products are contained within a single large-diameter “semi-visible” jet. The main parameters of our model are the mediator mass, the mass of the dark mesons, and the fraction of invisible stable particles. In the event of no discovery, the exclusion limits for mediator mass of 275 to 550 GeV are expected.