Nonperturbative three-point vertex in massless quenched QED and perturbation theory constraints


Bashir A., Kizilersu A., Pennington M.

PHYSICAL REVIEW D, cilt.57, ss.1242-1249, 1998 (SCI İndekslerine Giren Dergi) identifier identifier

  • Cilt numarası: 57 Konu: 2
  • Basım Tarihi: 1998
  • Doi Numarası: 10.1103/physrevd.57.1242
  • Dergi Adı: PHYSICAL REVIEW D
  • Sayfa Sayıları: ss.1242-1249

Özet

Dong, Munczek, and Roberts have shown how the full 3-point vertex that appears in the Schwinger-Dyson equation for the fermion propagator can be expressed in terms of a constrained function W-1 in massless quenched QED. However, this analysis involved two key assumptions: that the fermion anomalous dimension vanishes in the Landau gauge and that the transverse vertex has a simplified dependence on momenta. Here we remove these assumptions and find the general form for a new constrained function U-1 that ensures the multiplicative renormalizability of the fermion propagator nonperturbatively. We then study the restriction imposed on U-1 by recent perturbative calculations of the vertex and compute its leading logarithmic expansion. Since U-1 should reduce to this expansion in the weak coupling regime, this should serve as a guide to its nonperturbative construction. We comment on the perturbative realization of the constraints on U-1.