How good are the hard-pion calculations near the A₁ mass?

Abstract

We examine the possibility of relaxing the smoothness assumption in the hard-pion treatment of the A₁ρπ system. We retain the assumption of single-meson dominance of the propagators and impose the Bjorken limit on the primitive vertex function. When the relevant commutators are evaluated in the algebra of fields, a single new parameter is introduced. We find that the data on the ρ spin correlation can only be fitted by an A₁ width somewhat lower than the currently accepted one.