Off-shell ρ-ω mixing through quark loops with a nonperturbative meson vertex and quark mass functions
1995; American Institute of Physics; Volume: 51; Issue: 6 Linguagem: Inglês
10.1103/physrevc.51.3404
ISSN1538-4497
Autores Tópico(s)High-Energy Particle Collisions Research
ResumoThe momentum dependence of the off-shell \ensuremath{\rho}-\ensuremath{\omega} mixing amplitude is calculated through a two-quark loop diagram, using nonperturbative meson-quark vertex functions for the \ensuremath{\rho} and \ensuremath{\omega} mesons, as well as nonperturbative quark propagators. Both these quantities are generated self-consistently through an interlinked Bethe-Salpeter equation (BSE) cum Schwinger- Dyson equation (SDE) approach with a 3D support for the BSE kernel with two basic constants that are prechecked against a wide cross section of both meson and baryon spectra within a common structural framework for their respective 3D BSE's. With the precalibration, the on-shell strength works out at -2.434 \ensuremath{\delta}(${\mathit{m}}_{\mathit{q}}^{2}$) in units of the change in ``constituent mass squared,'' which is consistent with the ${\mathit{e}}^{+}$${\mathit{e}}^{\mathrm{\ensuremath{-}}}$ to ${\mathrm{\ensuremath{\pi}}}^{+}$${\mathrm{\ensuremath{\pi}}}^{\mathrm{\ensuremath{-}}}$ data for a u-d mass difference of 4 MeV, while the relative off-shell strength (0.99\ifmmode\pm\else\textpm\fi{}0.01) lies midway between quark-loop and QCD-SR results. We also calculate the photon-mediated \ensuremath{\rho}-\ensuremath{\omega} propagator whose off-shell structure has an additional pole at ${\mathit{q}}^{2}$=0. The implications of these results vis-a-vis related investigations are discussed.
Referência(s)