Evolution of Anisotropy of Parton System from Relativistic Heavy-Ion Collisions

Understand

Evolution of anisotropy in momentum and coordinate space of the parton system produced in relativistic heavy-ion collisions is discussed within the free-streaming approximation.

• The momentum distribution evolves from the prolate shape - elongated along the beam - to the oblate one - squeezed along the beam.
• At the same time the eccentricity in the coordinate space, which occurs at finite values of impact parameter, decreases.
• It is argued that the parton system reaches local thermodynamic equilibrium before the momentum distribution becomes oblate.