Signatures of collective behavior in small systems

21 May 2014, 09:20
europium (darmstadtium)



Schlossgraben 1 64283 Darmstadt Germany
Contributed Talk Correlations and Fluctuations Correlations and fluctuations


Igor Kozlov (McGill University)


We perform 3+1D viscous hydrodynamic calculations of proton-nucleus and nucleus-nucleus collisions. The goal is to ascertain the nature of the striking correlations seen in recent proton-nucleus collisions. In particular, one would like to know: is the observed ridge a signature of collective behavior? Can the highest multiplicity collision systems be accurately described as a relativistic fluid? If so, at what point does hydrodynamics fail to describe the bulk evolution? To this end, we propose to measure the detailed transverse momentum structure of two-particle correlations. They must satisfy rigid inequality relations in any hydrodynamic system, and within those bounds we show that they should have a particular dependence on multiplicity over the entire measured centrality range. Any deviation from this behavior would signal a breakdown of a hydrodynamic description. We also show how a simultaneous description of Pb-Pb and p-Pb data can put a significant constraint on theoretical models. Finally, we compare our calculations to the full set of existing measurements, demonstrating what parameters are required for a good fit to data and commenting on what can be learned.
On behalf of collaboration: JET

Primary authors

Igor Kozlov (McGill University) Matthew Luzum (McGill / LBNL)


Charles Gale (McGill University) Gabriel Denicol (McGill University) Sangyong Jeon (McGill University)

Presentation Materials