Speaker
VASILE TOPOR POP
(McGill University, Montreal, Canada)
Description
With the HIJING/BBar v2.0 event generator, we explore the phenomenological consequences of the suppression of perturbative quantum chromo-dynamics (pQCD) mini-jet production and of enhanced "in medium" strong longitudinal color field. Nuclear effects like shadowing and parton energy loss ("jet quenching") are included.
This analysis focuses on p+p collisions at centre of mass energy
(sqrt(sNN)) 0.900, 2.36 and 7 TeV, and
on central Pb+Pb collisions at sqrt(sNN) = 2.76 TeV, where recent data
have been reported by LHC Collaborations (ALICE, ATLAS, CMS).
The effective energy-dependent string tension values are constrained by p+p data from Relativistic Heavy Ion Collider (RHIC), the Tevatron, and recent Large Hadron Collider (LHC) runs. The pQCD cut-off value p0(s) is constrained by Au+Au collisions data from RHIC. Data on charged hadron multiplicity and charged hadron nuclear modification factor (RAA) in central (0-5%) Pb+Pb collisions from the ALICE experiment at the LHC are used to constrain the main parameters of the "jet quenching" phenomena (energy loss and mean free path of initial parton-parton interactions). Predictions for the energy and centrality dependence of rapidity densities (2dNch/dy/Npart) and the hadron flavor dependence(mesons and baryons) of the nuclear modification factor RAA are presented. By studying baryon/meson ratios, we show that the jet quenching in central collisions suppresses the hard pQCD component of the particle spectra, thereby exposing a novel component of baryon dynamics that we attribute to (gluonic) baryon-anti-baryon junctions (JJbar). We predict that a baryon/mesons anomaly at intermediate transverse momentum values will persist at LHC energies, with a moderate centrality dependence.
(*) This work is being supported by NSERC (Canada) and by the
US Department of Energy.
Author
VASILE TOPOR POP
(McGill University, Montreal, Canada)
Co-authors
Charles Gale
(McGill University, Montreal, Canada)
Jean Barrette
(McGILL UNIVERSITY, MONTREAL, CANADA)
Miklos Gyulassy
(Columbia University, New York, USA)
