Scaling properties of fractional momentum loss of high- hadrons in nucleus-nucleus collisions at from 62.4 GeV to 2.76 TeV

Adare, A.*; Hasegawa, Shoichi   ; Imai, Kenichi; Nagamiya, Shoji; Sako, Hiroyuki   ; Sato, Susumu  ; Tanida, Kiyoshi   ; PHENIX Collaboration*; 623 of others*

Measurements of the fractional momentum loss () of high-transverse-momentum-identified hadrons in heavy-ion collisions are presented. Using in Au+Au and Cu+Cu collisions at = 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 as a function of a number of variables: the number of participants, , the number of quark participants, , the charged-particle density, , and the Bjorken energy density times the equilibration time, . We find that the , where has its maximum, varies both with centrality and collision energy. Above the maximum, tends to follow a power-law function with all four scaling variables. The data at = 200 and 2.76 TeV, for sufficiently high particle densities, have a common scaling of with and , lending insight into the physics of parton energy loss.