Experimental HEP Seminar

Anomalous baryon production in p+p and Pb+Pb collisions at the LHC

Vasile Topor Pop

Department of Physics
McGill University

With the HIJING/BBbar v2.0 event generator, we explore the phenomenological consequences of the suppression of perturbative quantum chromodynamics (pQCD) mini-jet production, of the enhanced “in medium” strong longitudinal color field (SCF) and of (gluonic) baryon-anti-baryon junctions (JJbar loops). This analysis focused on p+p collisions at centre of mass energies √s = 0.900, 2.36 and 7 TeV and on Pb+Pb collisions at √s_NN = 2.76 TeV, where recent data have been reported by LHC Collaborations (ALICE, ATLAS, CMS).

We show that combined effects of hard and soft sources of multiparticle production can reproduce the available p+p data in range 0.02 < √s < 7 TeV assuming a dependence of the effective string tension, Κ, on energy Κ(s) = Κ₀(s/s₀)^0.06 GeV/fm.

Predictions for the energy and centrality dependence of rapidity densities (2dN_ch/dy)/N_part) and especially the hadron flavor dependence (mesons and baryons) of the nuclear modification factor R_AA(p_T) are discussed for central (0-5%) Pb+Pb collisions. We predict also that abaryon/mesons anomaly at intermediate transverse momentum values (p_T<10 GeV/c) will persist at LHC energies, with a moderate centrality dependence.