1112.4760 (Adrian Dumitru et al.)

Initial conditions for dipole evolution beyond the McLerran-Venugopalan
model    [PDF]

Adrian Dumitru, Elena Petreska

We derive the scattering amplitude N(r) for a QCD dipole on a dense target in
the semi-classical approximation. We include the first subleading correction in
the target thickness arising from ~\rho^4 operators in the effective action for
the large-x valence charges. Our result for N(r) can be matched to a
phenomenological proton fit by Albacete et al over a broad range of dipole
sizes r and provides a definite prediction for the A-dependence for heavy-ion
targets. We find a suppression of N(r) for finite A for dipole sizes a few
times smaller than the inverse saturation scale, corresponding to a suppression
of the classical bremsstrahlung tail.

View original: http://arxiv.org/abs/1112.4760