Charge symmetry, quarks and mesons

$\rho - \omega$ mixing, vector meson dominance and the pion form-factor

▪ Abstract Charge symmetry breaking (CSB) in the strong interaction occurs because of the difference between the masses of the up and down quarks. The use of effective field theories allows us to follow this influence of confined quarks in hadronic and nuclear systems. We review the progress in observing and understanding CSB, with particular attention to the recent successful observations of CSB in measurements involving the production of a single neutral pion, and to the related theoretical progress.

https://www.annualreviews.org/doi/pdf/10.1146/annurev.nucl.56.080805.140446

Charge Symmetry Breaking and QCD

The role ofρ-ω mixing as a mechanism for charge-symmetry violation in the nucleon-nucleon system is apparently well established. However, a common assumption in generating the charge-symmetry-violation potential is that theρ-ω mixing amplitude is constant (at the on-mass-shell value) even when the exchanged meson is far off-shell. We construct a simple quark model in which the mixing is generated by theu-d quark mass difference which allows us to test this assumption. It turns out to be surprisingly poor.

B. Holzenkamp

Papers

Consistent evaluation of charge-symmetry breaking effects in the neutron-proton interaction