  We study the process $qq\rightarrow qqg$ at lowest order in QCD perturbation
theory to understand gluon radiation in the fragmentation region of
relativistic heavy-ion collisions. We arrive at a formula for gluon
multiplicity that interpolates between $\sim 1/k_{\bot}^2$ behavior at low
$k_{\bot}$, to $\sim 1/k_{\bot}^4$ at large $k_{\bot}$.

High Energy Physics - Phenomenology