Radiative Transport and Heavy Ion Collisions

Dustin R Hemphill, Purdue University

Abstract

The good agreement of relativistic, dissipative hydrodynamics with heavy ion experiments at the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider seems to indicate that the medium produced in the collision is near local equilibrium. However, the mechanism of the observed rapid equilibration is still an unsolved problem. While elastic 2 → 2 perturbative QCD rates do not quickly thermalize or produce large elliptic flow, it has been claimed that perturbative gg ↔ ggg rates can equilibrate rapidly. To investigate rapid equilibration via gg ↔ ggg, the partonic stage of a heavy ion collision is modeled using covariant kinetic theory. The key achievement of this thesis work is the implementation of leading order perturbative QCD matrix elements for gg ↔ scattering in a stochastic Boltzmann transport solver algorithm, in order to facilitate studies that include both elastic gg → gg and radiative gg ↔ ggg interactions. The role of the invariant matrix element and screening technique in equilibration and the generation of elliptic flow are then investigated by calculating the total cross section, equilibrium collision rates, and elliptic flow in Au + Au collisions at RHIC. This work has found that collision rates and elliptic flow results strongly depend on the choice of gg → ggg matrix element and screening technique.

Degree

Ph.D.

Advisors

Molnar, Purdue University.

Subject Area

Physics

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