arXiv subjects

Adrian Dumitru

Publications and source records attributed to Adrian Dumitru.

113 records · Page 7Linked to original sources

arXiv2000

The Effective Pressure of a Saturated Gluon Plasma

The evolution of the gluon plasma produced with saturation initial conditions is calculated via transport theory for nuclear collisions with 0.1 <sqrt(s) <10 A TeV. The effective longitudinal pressure is found to remain significantly below the lattice QCD pressure with these initial conditions until the plasma cools to near the confinement scale. The absolute value of the transverse energy per unit of rapidity and its dependence on beam energy is shown to provide a sensitive test of gluon saturation models since the fractional transverse energy loss due to final state interactions is predicted to be much smaller and exhibit a weaker energy dependence than nondissipative hydrodynamics applied throughout the evolution.

hep-ph↗

arXiv2000

Collective Evolution of Hot QCD Matter from the QGP to Freeze-Out

We present results on the evolution of with energy, for hadrons emerging from hadronization of a quark-gluon plasma possibly produced in high-energy heavy-ion collisions. We find that BNL-RHIC energy corresponds to the previously predicted plateau of , reminiscent of the assumed first-order QCD phase transition. Heavy hadrons are the best messengers of the transverse flow stall.

nucl-th↗

arXiv2000

Nonlinear evolution of the momentum dependent condensates in strong interaction: the ``pseudoscalar laser''

We discuss the relaxation of the scalar and pseudoscalar condensates after a rapid quench from an initial state with fluctuations. If we include not only the zero-mode but also higher modes of the condensates in the classical evolution, we observe parametric amplification of those ``hard'' modes. Thus, they couple nonlinearly to the ``soft'' modes. As a consequence, domains of coherent pi-field emerge long after the initial spinodal decomposition. The momentum-space distribution of pions emerging from the decay of that momentum-dependent condensate is discussed.

hep-ph↗

arXiv1999

Calculation of the expansion rate of the three-volume measure in high-energy heavy-ion collisions

In ultrarelativistic heavy-ion collisions the local three-volume measure is expanding in the longitudinal and transverse directions. This is similar to the Hubble-expansion of the universe, except that the former is not locally isotropic. As an example the expansion rate is calculated assuming that the energy-momentum tensor in the central region is that of an ideal fluid, undergoing Bjorken flow in longitudinal direction, and with initial conditions as expected for BNL-RHIC energy. While the longitudinal expansion of three-volume is independent of the energy density of the fluid, in case of 3+1 dimensional expansion the form of the hydrodynamical solution (rarefaction wave or deflagration shock) affects the three-volume expansion rate on the hadronization hypersurface. As a consequence the average expansion rate on that surface depends on the transverse size of the system. This may reflect in an impact-parameter dependence of the formation probability of light nuclei and of the freeze-out temperature of the strong interactions in the system.

hep-ph↗

arXiv1998

Effect of quark-jet energy loss on direct photons in ultrarelativistic heavy-ion collisions

We discuss the transverse momentum distribution of thermal and prompt photons in ultrarelativistic heavy ion collisions. The prompt photons are mostly produced by fragmentation of quark jets (bremsstrahlung). If these quark jets suffer a large energy loss in heavy-ion reactions, prompt photons are significantly suppressed. Thermal electromagnetic radiation from the quark-gluon plasma and the hadron gas might then dominate the intermediate k_T-range. In central Au+Au collisions at \sqrt{s}=200A GeV, and in the range 2 GeV < k_T < 4 GeV, the inverse slope of the thermal radiation is 360-460 MeV, while that of the QCD photons is 500-1000 MeV. This large difference might allow to disentangle the various sources of direct photons experimentally. At \sqrt{s}=5.5A TeV, nuclear shadowing and quark-jet quenching suppresses the QCD-photons strongly for k_T<5 GeV. Thermal radiation dominates in this k_T-region.

hep-ph↗