Two Particle Angular Correlation Functions of Neutral and Charged Kaons in Pb–Pb collisions at √sNN = 5.02 TeV with ALICE Experiment at the Large Hadron Collider
In ultra-relativistic heavy-ion collisions, hadronic matter undergoes transition to a deconfined phase of quarks and gluons, a state of matter widely known as Quark-Gluon Plasma (QGP). It is believed that the universe existed in this new state of matter microseconds after the Big Bang. The QGP state is transient, undergoing collective expansion and eventually hadronizing. Phase transitions in Quantum Chromodynamics (QCD) are also realized in terms of chiral symmetry breaking/restoration. In the confined hadronic phase, chiral symmetry is broken and it is expected to be restored in the deconfined QGP phase. This was verified by Lattice QCD calculations at finite temperatures and zero densities. There have been several experimental evidences for the deconfinement phase transition while the chiral phase transition remains as a mystery for high energy physicists. Observing signals of chiral phase transition is as fundamental a feature of QCD as quark or color confinement and asymptotic freedom. Recent ALICE measurements have demonstrated large dynamical correlations between produced neutral and charged kaons in Pb–Pb collisions at √sNN = 2.76 TeV. These integrated correlations cannot be described by conventional heavy-ion models, such as HIJING, EPOS-LHC and AMPT; however, they can only be explained by invoking the presence of a condensate. Two candidates for such a condensate are the Disoriented Chiral Condensate (DCC) and Disoriented Isospin Condensate (DIC). They both arise from chiral symmetry restoration in the QGP, which breaks during the phase transition to form a condensate that coherently emits hadrons. To further investigate these anomalous kaon correlations, a differential measurement of two-particle angular correlation functions of charged and neutral kaons as a function of Δφ and Δη in Pb–Pb collisions at √sNN = 5.02 TeV is performed in this dissertation. The correlations involving oppositely charged kaons were computed as a baseline. These experimental correlations were then compared with HIJING and AMPT model predictions to determine if the angular correlations exhibited any anomalous behavior.