Thermalization of a color glass condensate and review of the "Bottom-Up" scenario

Understand

Thermalization of a longitudinally expanding color glass condensate with Bjorken boost invariant geometry is investigated within microscopical parton cascade BAMPS.

• Our main focus lies on the detailed comparison of thermalization, observed in BAMPS with that suggested in the \BUp scenario.
• We demonstrate that the tremendous production of soft gluons via $gg \to ggg$, which is shown in the \BUp picture as the dominant process during the early preequilibration, will not occur in heavy ion collisions at RHIC and LHC energies, because the back reaction $ggg\to gg$ hinders the absolute particle multiplication.
• Moreover, different from the \BUp scenario, soft and hard gluons thermalize at the same time.