title: Gauge coupling unification in grand unified theories with anomalous U1 symmetry.
abstract: We show that in the framework of grand unified theory (GUT) with anomalous U(1)(A) gauge symmetry, the success of the gauge coupling unification in the minimal SU(5) GUT is naturally explained, even if the mass spectrum of superheavy fields does not respect SU(5) symmetry. Because the unification scale for most realizations of the theory becomes smaller than the usual GUT scale, it suggests that the present level of experiments is close to that sufficient to observe proton decay via dimension 6 operators, p-->e+pi.
authors.affiliation: Department of Physics, Kyoto University, Kyoto 606-8502, Japan.
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Maekawa
authors.forename: Toshifumi
authors.initials: T
authors.lastname: Yamashita