Study of light nuclei (antinuclei) production and Photon Multiplicity Detector in ALICE at the LHC

The primary goal of the heavy-ion program at the Large Hadron Collider (LHC) at CERN, Geneva, Switzerland is to search for the possible formation of Quark-Gluon Plasma. It also aims to understand the production mechanism of matter and antimatter in a collision. The details of the ALICE detector and its subsystems are presented in this thesis. The details of the fabrication, electronics, readout and installation of the PMD (Photon Multiplicity Detector) in the ALICE experiment are also presented. The PMD detector measures the photons in the 2.3 $<$ $\eta$ $<$ 3.7 region. The software details including the reconstruction chain are also discussed. The detailed study of efficiency and purity calculation for the PMD detector using the embedding technique are also presented for pp and Pb-Pb collisions. The detailed study of nuclei and anti-nuclei production using the statistical-thermal model (THERMUS) is discussed. Their ratios are compared with the existing experimental data and predictions are made for pp and heavy-ion collisions at RHIC and LHC energies. The first measurements of nuclei and anti-nuclei like d ($\bar{\rm d}$), t ($\bar{\rm t}$) and $^{3}$He ($^{3}\overline{\rm He}$) production in the ALICE experiment for pp and Pb-Pb collisions at $\sqrt{s}$ = 7 TeV and $\sqrt{s_{\rm NN}}$ = 2.76 TeV respectively, are shown. The final spectra for nuclei are obtained and the particle ratios are compared with the statistical-thermal model predictions. The dependence of nuclei ratio on the chemical freeze-out temperature is also investigated. The year 2011 is marked with the discovery of anti-alpha by the STAR and ALICE experiments. The data analysis for the observation of anti-alpha ($^{4}\overline{\rm He}$) in Pb-Pb collisions at $\sqrt{s_{\rm NN}}$ = 2.76 TeV by the ALICE experiment is presented in this thesis.