title: Nonlocal anomaly of the axial-vector current for bound states.
abstract: We argue that the amplitude <rho(gamma)/delta(nu)(q(gamma)(nu)gamma(5)q)/0> does not vanish in the limit of zero quark masses. This represents a new kind of violation of the classical equation of motion for the axial current and should be interpreted as the axial anomaly for bound states. The anomaly emerges in spite of the fact that the one loop integrals are ultraviolet finite as guaranteed by the finite size of bound-state wave functions. As a result, the amplitude behaves like approximately 1/p(2) in the limit of a large momentum p of the current. The observed effect requires the modification of the classical equation of motion of the axial-vector current by nonlocal operators.
authors.affiliation: Institut für Theoretische Physik, Universität Heidelberg, Philosophenweg 16, D-69120, Heidelberg, Germany.
authors.forename: Dmitri
authors.initials: D
authors.lastname: Melikhov
authors.forename: Berthold
authors.initials: B
authors.lastname: Stech