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Greg Mahlon McGill The McLerran-Venugopalan model is a fairly recent attempt to calculate from QCD the distribution of partons within very large nuclei. At first, the large nucleus problem sounds much harder than the single hadron problem. However, it can be argued that, at lowest order, for small x and moderate values of the transverse momentum, it is reasonable to consider the classical field generated by the valence quarks, which appear as a pizza-shaped distribution of color charge. In this talk I will present the McLerran-Venugopalan model as originally conceived by its inventors. Then I will describe an inconsistency in their treatment which leads to correlation functions which grow like (x2)(x2) at large distances. Requiring that the nucleons be color-neutral will tame this unphysical behaviour, and lead to a gluon number density which remains finite as q2 approaches 0.
Tuesday, May 4th 1999, 13:00 |