Gluon field of a fast moving nucleus and the effective Lagrangian for QCD at high energy - art. no. 054006

Starting from the effective Lagrangian for QCD at high energy we calculate the lowest perturbative contributions to the potential of a relativistic nu cleus and compare our results to those derived by Kovchegov [see Y.V. Kovch egov, Phys. Rev. D 55, 5445 (1997)]. The results differ already at order g( 3) which can be traced to the fact that the meaning of the underlying gluon fields is different. (The effective gluon field we use is a gauge-invarian t object.) Both approaches should therefore be seen as alternatives, the re lative merits of which have to be judged by their phenomenological success. [S0556-2821(99)01715-4].