Minijet scale and energy loss at relativistic energies in event generator models

作者：Pop VT^*; Gyulassy M; Barrette J; Gale C; Wang XN; Xu N; Filimonov K

来源：Physical Review C, 2003, 68(5): 054902.

DOI：10.1103/PhysRevC.68.054902

Recent data from relativistic heavy ion collider on rapidity and transverse momentum distributions of hadrons produced in ultrarelativistic reaction of both Au+Au and p+p are compared to predictions of the HIJING and RQMD models. The original default minijet scale p(0)=2 GeV /c and energy loss, dE/dx=2 GeV /fm in HIJING lead to a too rapid growth of the multiplicity with energy. RQMD model without minijet leads on the other hand to a too slowly increasing multiplicity with energy. Therefore, we study what variations of p(0) and dE/dx are required in HIJING to account for the observed N-part and roots dependence of the global dN(ch)/dy and dE(T)/dy observables as well as the jet quenching pattern out to p(T)similar to8 GeV . We show that a slight increase of p(0) from the default 2.0 GeV/c at roots=130A GeV to 2.2 GeV/c at roots=200A GeV is sufficient to account for the bulk observables. Jet quenching of pi(0) above p(T)>4 GeV/c at 200A GeV is found to be well reproduced in central Au+Au by the original HIJING default prediction. However, the effective surface emission in the HIJING model formulation of energy loss overpredicts the quenching in more peripheral collisions. Neither HIJING nor HIJING /B (B) over bar can account for the observed anomalous excess of moderate p(T)<4 GeV/c baryons. The agreement of RQMD with data in this p(T) region is shown to be fortuitous because, without minijets, it fails to reproduce the p+p spectrum.

• 出版日期2003-11
• 单位McGill