engleski

Scaling properties of fractional momentum loss of high-pT hadrons in nucleus-nucleus collisions at sqrt(s_NN) from 62.4 GeV to 2.76 TeV

Measurements of the fractional momentum loss (Sloss≡δpT/pT) of high-transverse-momentum- identified hadrons in heavy-ion collisions are presented. Using π0 in Au+Au and Cu+Cu collisions at sqrt(s_NN)=62.4 and 200 GeV measured by the PHENIX experiment at the Relativistic Heavy Ion Collider and and charged hadrons in Pb+Pb collisions measured by the ALICE experiment at the Large Hadron Collider, we studied the scaling properties of Sloss as a function of a number of variables: the number of participants, Npart, the number of quark participants, Nqp, the charged- particle density, dNch/dη, and the Bjorken energy density times the equilibration time, ɛBjτ0. We find that the pT, where Sloss has its maximum, varies both with centrality and collision energy. Above the maximum, Sloss tends to follow a power- law function with all four scaling variables. The data at sNN=200 GeV and 2.76 TeV, for sufficiently high particle densities, have a common scaling of Sloss with dNch/dη and ɛBjτ0, lending insight into the physics of parton energy loss.

QGP; identified hadrons; pt scaling

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