Event Shape Dependence of Symmetry Plane Correlations in Pb-Pb Collisions at the LHC Energies using AMPT

Abstract

Anisotropy in final state particle emission in Pb-Pb collisions at √𝑠NN = 5.02 TeV is expected to arise as a consequence of anisotropy in energy distribution of the initial colliding system. This thesis aims to explore and comprehend the configuration of initial energy distribution using the correlations in symmetry plane angles corresponding to the anisotropy of final state particle emission in the transverse momentum space in Pb-Pb collisions at √𝑠NN = 5.02 TeV which have been generated using A Multi-Phase Transport (AMPT) model. The Gaussian Estimator (GE) has been used for the purpose of evaluating the symmetry plane correlations (SPCs), as it provides information unbiased of the fluctuations of the anisotropy from one event to the other. In analogy to the GE of SPCs, participant plane correlations (PPCs) have been defined, which characterize the geometry of the initial colliding region in a way very similar to how SPCs characterize final state transverse momentum distribution. In this geometrical context, it is suggestive to carry out an event shape differentiated study of the SPCs in order to gain a better understanding regarding them. The event shape classifier used for this purpose is transverse spherocity. While most of the SPCs show striking contrast in different event shape classes, the PPCs show no such difference. Most of the SPCs exhibit qualitatively, the same centrality dependence as their corresponding PPCs. In this study, a linear relationship between some SPCs and their corresponding PPCs have been found in Pb-Pb collisions at the LHC energies, generated with AMPT. This work could find application by providing geometry based physical insight into the development of models using Bayesian analysis for deciding the best values of parameters, as each SPC and their corresponding PPC give unique information regarding the geometry of the respective states of the collision system that they are defined in.