QCD EVOLUTION OF THE GLUON DENSITY IN A NUCLEUS

The Glauber approach to the gluon density in a nucleus, suggested by A . Mueller, is developed and studied in detail. Using the GRV parameter ization for the gluon density in a nucleon, the value as well as energ y and Q(2) dependence of the gluon density in a nucleus is calculated. It is shown that the shadowing corrections are under theoretical cont rol and are essential in the region of small x. They crucially change the value of the gluon density as well as the value of the anomalous d imension of the nuclear structure function, unlike that of the nucleon . The systematic theoretical way to treat the corrections to the Glaub er approach is developed and a new evolution equation is derived and s olved. It is shown that the solution of the new evolution equation can provide a self-consistent matching of ''soft'' high energy phenomenol ogy with ''hard'' QCD physics. (C) 1997 Published by Elsevier Science B.V.