Monte Carlo glauber model : quadrupole correlations in Au+Au collisions




Bhattarai, Prabhat

Journal Title

Journal ISSN

Volume Title



The study of quarks and their interaction through gluons has been active area of research since its discovery. It has been about two decades that Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory is dedicated to study interaction between quarks by producing nuclear matter in extremely dense and hot environment. It has been understood that colliding beams of atomic nuclei at a speed close to the speed of light creates the hot and dense environment in which all quarks in the nuclei de-confine to form a short-lived state of matter called Quark Gluon Plasma (QGP). Because of the short lifetime of QGP, the only way to study such matter is through the final state of particles. A significant feature of the final state distribution of particles is an azimuthal anisotropy, which is dominated by the second Fourier component; the amplitude is proportional to parameter v2. One of the major interpretations of this anisotropy is based on the hypothesized thermal equilibrium of the QGP leading to pressure driven collective flow. The other is that quantum interference among many quark and gluon scatterings leads directly to anisotropy in the final state. The present report presents a way to calculate the observed quadrupole correlation amplitude, v2, without assuming collective flow. The study uses a Monte Carlo method to simulate the gold-gold nuclear collision data using experimental results from proton-proton collisions. The quality of simulated results is assured by comparison to theoretical understanding of the phenomenon as well as to the experimental data. This report presents studies of two-particle correlations, whose derivation can be traced back to Pearson's correlation coefficient, in azimuthal angular space of the simulated tracks of the particles produced in the gold-gold of collisions. The correlation result is fitted to extract the v2 and compared to the same quantity from the experimental data. The comparison suggests that a fraction of the v2 in gold-gold collisions can be accounted for by phenomenon not associated with collective flow.



LCSH Subject Headings