Measurement of Mixing Parameters and CP Violaton in B Meson Decays using t-tbar Events at CMS

CP violation, one of the Sakharov conditions required to explain the baryon asymmetry of the universe, plays a key role in understanding the origin of our cosmos. This thesis covers study of mixing parameters of B mesons and possible CP violation in mixing. $\bar t - t$ events are used due to the high $p_T$ of their decay products which provide clearer experimental signatures. The thesis is particularly focused on the classification of the leptons coming from semileptonic decays of top quark and b hadrons and on the problem of tagging muons from the b hadrons to the top that b quark was born from. Further steps of the mixing parameters determination are discussed.