The study of Underlying Event activity and two particle Angular Correlation with particles and Z boson using low pileup data

Abstract

newline School of Physics and Materials Science xii newlineABSTRACT newlineThis thesis presents the measurement of underlying events and angular correlations with Z-boson and other tracks. The measurement is performed with proton-proton collision data at a centre-of-mass energy of 5 TeV and 13 TeV, collected by the CMS experiment at the LHC in the year 2017. This collision data corresponds to an integrated luminosity 134.31 pb-1 and 200 pb-1 respectively. The study of the Underlying Event is very important, and a good understanding of the underlying events properties is important for the precise measurement of the SM process and the search for new physics at high energy. Secondly, the measurements of two-particle correlations are a powerful tool to study the underlying mechanism of particle production in collisions of hadrons and nuclei at high energy. Angular correlations are typically studied using two-dimensional and#916;and#951;-and#916;and#966; correlation functions. For both the studies, and#916;and#951; is the difference in pseudorapidities and#951; and and#916;and#966; is the difference in their azimuthal angle and#966; (in radians) between Z-boson with muonic final state and other tracks excluding muon tracks.