Gluon Bremsstrahlung in Weakly-Coupled Plasmas

Abstract

I report on some theoretical progress concerning the calculation of gluon bremsstrahlung for very high energy particles crossing a weakly-coupled quark-gluon plasma. (i) I advertise that two of the several formalisms used to study this problem, the BDMPS-Zakharov formalism and the AMY formalism (the latter used only for infinite, uniform media), can be made equivalent when appropriately formulated. (ii) A standard technique to simplify calculations is to expand in inverse powers of logarithms $\ln (E/T)$. I give an example where such expansions are found to work well for $\omega /T\gtrsim 10$ where $\omega$ is the bremsstrahlung gluon energy. (iii) Finally, I report on perturbative calculations of $\hat{q}$.

Comments: 4 pages, 2 figures - To appear in the conference proceedings for Quark Matter 2009, March 30 - April 4, Knoxville, Tennessee [change from v2: minor changes for publication]