Event by event di-hadron correlations in Pb-Pb 2.76 TeV collisions from the ALICE experiment

Understand

The large multiplicities at the LHC may permit flow harmonics to be determined on an event by event basis in Pb-Pb collisions.

• We extract these harmonics from event by event di-hadron correlations.
• Within a fine centrality bin, we find the correlation function varies substantially on an event by event basis, indicating large fluctuations in the initial conditions for a given impact parameter.
• Such large fluctuations lead to some events being highly triangular or highly elliptical, where the angular correlation function is completely dominated by the respective second and third Fourier harmonics.