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Typical working day..

Roman Pasechnik

Senior lecturer

Typical working day..

A heuristic description of high-p(T) hadron production in heavy ion collisions


  • Jan Nemchik
  • Roman Pasechnik
  • Irina Potashnikova

Summary, in English

Using a simplified model for in-medium dipole evolution accounting for color filtering effects we study the production of hadrons at large transverse momenta p(T) in heavy ion collisions. In the framework of this model, several important sources of the nuclear suppression observed recently at RHIC and LHC have been analyzed. A short production length of the leading hadron l(p) causes a strong onset of color transparency effects, manifesting themselves as a steep rise of the nuclear modification factor RAA(p(T)) at large hadron p(T). The dominance of quarks with higher l p leads to a weaker suppression at RHIC than the one observed at LHC. In the RHIC kinematic region we include an additional suppression factor, steeply falling with p(T), which is tightly related to the energy conservation constraints. This is irrelevant at LHC up to p(T) less than or similar to 70 GeV, while it causes a rather flat p(T) dependence of the R-AA(p(T)) factor at RHIC c. m. energy root s = 200 GeV and even an increasing suppression with p(T) at root s = 62 GeV. The calculations contain only a medium density adjustment, and for an initial time scale t0 = 1 fmwe found the energy-dependent maximal values of the transport coefficient, (q) over cap (0) = 0.7, 1.0, and 1.3GeV(2)/fm, corresponding to root s = 62, 200 GeV, and 2.76 TeV, respectively. We present a broad variety of predictions for the nuclear modification factor and the azimuthal asymmetry, which are well in agreement with available data from experiments at RHIC and LHC.


  • Theoretical Particle Physics

Publishing year





European Physical Journal C. Particles and Fields





Document type

Journal article




  • Subatomic Physics




  • ISSN: 1434-6044