Georg Wolschin

Baryon Stopping as a New Probe of Geometric Scaling

We suggest using net-baryon rapidity distributions in central relativistic heavy-ion collisions at energies reached at the CERN Super Proton Synchrotron, BNL Relativistic Heavy-Ion Collider (RHIC), and CERN LHC in order to probe saturation physics. Within the color glass condensate framework based on small-coupling QCD, net-baryon rapidity distributions are shown to exhibit geometric scaling. In a comparison with RHIC data in Au+Au collisions at sqrt[sNN=62.4 GeV and 200 GeV the gradual approach to the gluon saturation regime is investigated. Predictions for net-baryon rapidity spectra and the mean rapidity loss in central Pb+Pb collisions at LHC energies of sqrt[sNN=5.52 TeV are made.

Particle production sources at LHC energies

Particle production sources at RHIC and LHC energies are investigated in pseudorapidity space. A nonequilibrium-statistical relativistic diffusion model with three sources is applied to the analysis of charged-hadron distributions in AuAu collisions at RHIC energies, in PbPb collisions at the current LHC energy of 2.76 TeV, in pPb at 5.02 TeV, and in pp. The size of the midrapidity source relative to the fragmentation sources in heavy-ion collisions is investigated as function of incident energy. At LHC energies, the midrapidity value is mostly determined by particle production from gluon–gluon collisions.

Bottomium suppression in PbPb collisions at LHC energies

We substantially refine our previously developed model for the suppression of Υ mesons in the quark–gluon plasma formed in 2.76 TeV PbPb collisions at the LHC. It accounts for gluodissociation of the six bottomium states Υ(ns), with , collisional damping of these states as described in a complex potential, screening of the real part of the potential, and the subsequent decay cascade. In the hydrodynamical calculation of the expanding fireball, we take into account the effect of transverse expansion on the suppression factors, and finite transverse momenta of the heavy mesons in the medium. The running of the coupling is considered, resulting in larger gluodissociation decay widths. The initial central temperature is found to be 550 MeV at 0.1 fm/c. Our results are in good agreement with recent centrality-dependent CMS and ALICE data. The calculated suppression of the excited states relative to the ground state Υ(1S) is not strong enough in peripheral collisions. Additional mechanisms are discussed. Predictions for 5.52 TeV are made.

Baryon stopping and saturation physics in relativistic collisions

We investigate baryon transport in relativistic heavy-ion collisions at energies reached at the CERN Super Proton Synchrotron (SPS), BNL Relativistic Heavy-Ion Collider (RHIC), and CERNs Large Hadron Collider (LHC) in the model of saturation. An analytical scaling law is derived within the color glass condensate framework based on small-coupling QCD. Transverse momentum spectra, net-baryon rapidity distributions, and their energy, mass, and centrality dependencies are well described. In comparison with RHIC data in

From RHIC to LHC: a relativistic diffusion approach

\mathrm{Au}+\mathrm{Au}

Rapidity equilibration and longitudinal expansion at RHIC

collisions at

Beyond the thermal model in relativistic heavy-ion collisions

\sqrt{{s}_{\mathit{NN}}}=62.4

Particle production and nonlinear diffusion in relativistic systems

and

Strong-coupling diffusion in relativistic systems

200

Equilibration in finite Bose systems

GeV, the gradual approach to the gluon saturation regime is investigated and limits for the saturation-scale exponent are determined. Predictions for net-baryon rapidity spectra and the mean rapidity loss in central