Anisotropic Flow Measurement in Ultra-Central Pb-Pb Collisions For Run 10 and Run 11 by ALICE



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The mission of relativistic heavy-ion collisions is to create an extremely hot and dense medium where the quarks and gluons become deconfined from their typical hadronic states. This unique state of matter is known as the Quark-Gluon Plasma (QGP). The collective flow of the system plays a critical role in establishing the equation of state of the QGP. Among different orders of azimuthal flow, the second order elliptic flow receives keen attention and will be analyzed in the ultra-central collision centrality range. Various hydrodynamic simulations show that vn correlates almost linearly with the initial eccentricity εn of the system (which fluctuates on an event by event basis). This indicates that the measurement of vn fluctuations are extremely sensitive to the initial state configuration. This thesis will analyze higher order cumulants, and investigate how they can constrain the initial state. The second order flow (v2) from 2, 4, and 6-particle correlations for LHC Runs 10 and 11 of Pb-Pb collisions at the center of mass energy sNN = 2.76 TeV are presented. A series of statistical and systematic uncertainty checks for data collected from Run 10 and Run 11 was performed, and the usefulness of the measured results in their theoretical context will be discussed.



Anisotropic flow, V2, Second order flow, Collective expansion, Qgp, Quark-gluon plasma, High energy physics