  We investigate the transition from the nucleon-meson to quark-gluon
description of the strong interaction using the photon energy dependence of the
$d(\gamma,p)n$ differential cross section for photon energies above 0.5 GeV and
center-of-mass proton angles between $30^{\circ}$ and $150^{\circ}$. A possible
signature for this transition is the onset of cross section $s^{-11}$ scaling
with the total energy squared, $s$, at some proton transverse momentum, $P_T$.
The results show that the scaling has been reached for proton transverse
momentum above about 1.1 GeV/c. This may indicate that the quark-gluon regime
is reached above this momentum.
