Anisotropic Flow Fluctuations in Very Central Pb-Pb √(s_NN ) = 2.76 TeV Collisions

An extremely hot and dense medium where quarks and gluons become deconfined from their typical hadronic states known as the Quark-Gluon Plasma (QGP), is created at the Large Hadron Collider (LHC). The collective flow of the system plays a critical role in establishing the equation of state for QGP. Among the different orders of azimuthal flow, the second order elliptic flow (v_2) has received much attention, and will be analyzed in the ultra-central collision (0-5%) centrality range. Various hydrodynamic simulations show that v_2 correlates almost linearly with the initial eccentricity ε_2 of the system (which fluctuates on an event by event basis). Measurements of v_2 fluctuations are extremely sensitive to the initial state configuration. An unfolding method has been used to obtain the underlying v_2 distributions from Pb-Pb collisions with a center of mass energy per nucleon of 2.76 TeV.