Charge symmetry breaking via rho-omega mixing from model quark-gluon dynamics

Abstract

The quark-loop contribution to the ${\rho }^0-\omega$ mixing self-energy function is calculated using a phenomenologically successful QCD-based model field theory in which the ${\rho }^0$ and $\omega$ mesons are composite $\bar{q}q$ bound states. In this calculation the dressed quark propagator, obtained from a model Dyson-Schwinger equation, is confining. In contrast to previous studies, the meson-$\bar{q}q$ vertex functions are characterised by a strength and range determined by the dynamics of the model; and the calculated off-mass-shell behaviour of the mixing amplitude includes the contribution from the calculated diagonal meson self-energies. The mixing amplitude is shown to be very sensitive to the small isovector component of dynamical chiral symmetry breaking. The spacelike quark-loop mixing-amplitude generates an insignificant charge symmetry breaking nuclear force.

Comments: 11 Pages, 3 figures uuencoded and appended to this file, REVTEX 3.0. ANL-PHY-7718-TH-94, KSUCNR-004-94. [!! PostScript file format corrected. Retrieve by anonymous ftp from theory.phy.anl.gov (130.202.20.190), directory pub: mget wpfig*.ps Three files.]