Jet quenching in strongly coupled plasma

Understand

We present calculations in which an energetic light quark shoots through a finite slab of strongly coupled ${\cal N}=4$ supersymmetric Yang-Mills (SYM) plasma, with thickness $L$, focussing on what comes out on the other side.

• We find that even when the "jets" that emerge from the plasma have lost a substantial fraction of their energy they look in almost all respects like "jets" in vacuum with the same reduced energy.
• The one possible exception is that the opening angle of the "jet" is larger after passage through the slab of plasma than before.
• Along the way, we obtain a fully geometric characterization of energy loss in the strongly coupled plasma and show that $dE_{\rm out}/dL \propto L^2/\sqrt{x^2_{\rm stop}-L^2}$, where $E_{\rm out}$ is the energy of the "jet" that emerges from the slab of plasma and $x_{\rm stop}$ is the (previously known) stopping distance for the light quark in an infinite volume of plasma.