相关论文: Charge symmetry breaking via rho-omega mixing from…
The momentum-dependence of the $\rho^0$-$\omega$ mixing contribution to charge-symmetry breaking (CSB) in the nucleon-nucleon interaction is compared in a variety of models. We focus in particular on the role that the structure of the quark…
We study the self-energy amplitudes for the rho-omega meson system produced by an effective field theory model at the quark level characterized by a finite range quark-quark interaction and an isospin breaking bare quark mass difference…
The momemtum dependence of the off-shell $\rho$-$\omega$ mixing amplitude is calculated through a two-quark loop diagram, using non-perturbative meson-quark vertex functions for the $\rho$ and $\omega$ mesons, as well as non-perturbative…
It is shown that including form factors for the quark-pseudoscalar meson couplings of the Georgi-Manohar chiral quark model allows one to obtain the leading off-shell dependence of $\pi^{o}- \eta$ mixing (as predicted by chiral perturbation…
In this paper, U(3)$_L\times$ U(3)$_R$ chiral theory of mesons is extended to the leading order in quark mass expansion in order to evaluate the $\rho^0-\omega$ mixing. It is shown that the use of path integral method to integrate out the…
Charge independence and symmetry are approximate symmetries of nature. The observations of the small symmetry breaking effects and the consequences of those effects are reviewed. The effects of the mass difference between up and down quarks…
The role of the off-shell dependence of $\rho-\omega$ mixing in the charge symmetry breaking nucleon-nucleon potential is discussed. It is shown that models describing the off-shell dependence of $\rho-\omega$ mixing are not sufficient to…
We present a relativistic mean-field model that incorporates charge symmetry breaking (CSB) of nuclear force via $ \omega $-$ \rho^0 $ meson mixing, along with corrections to the electromagnetic interaction including the nucleon form…
Two model-independent results on the momentum-dependence of $\rho$-$\omega$ mixing are described. First, an explicit choice of interpolating fields for the vector mesons is displayed for which both the mixing in the propagator and the…
It is pointed out that the meson mixing matrix elements usually considered responsible for the bulk of the observed few-body charge symmetry breaking are naturally $q^2$-dependent in QCD. For $\pi^o-\eta$ mixing, using the usual…
We compute isospin-violating meson-nucleon coupling constants and their consequent charge-symmetry-breaking nucleon-nucleon potentials. The couplings result from evaluating matrix elements of quark currents between nucleon states in a…
The $q^2$ dependence of the $\rho-\omega$ mixing amplitude is analyzed with the use of the QCD sum rules and the dispersion relation. Going off shell the mixing decreases, changes sign at $q^2 \simeq 0.4 m_{\rho}^2 > 0$ and is negative in…
Using a quark model, we study the effect of charge symmetry breaking on the valence quark distributions of the nucleon. The effect due to quark mass differences and the Coulomb interaction of the electrically charged quarks is calculated…
We investigate the splitting and mixing of $\rho$ and $\omega$ mesons in nuclear matter. The calculations were performed on the basis of QCD sum rules and include all operators up to mass dimension-6 twist-4 and up to first order in the…
We construct the charge symmetry violating (CSV) nucleon-nucleon potential induced by the $\rho^0$-$\o$ mixing due to the neutron-proton mass difference driven by the $NN$ loop. Analytical expression for for the two-body CSV potential is…
The $\rho\omega$--mixing generated by the isospin breaking of the current quark masses $m_{u} \neq m_{d}$ is studied within the bosonized NJL model in the gradient expansion. The resulting effective meson lagrangian naturally incorperates…
We investigate three models for the charge symmetry breaking (CSB) of the nucleon-nucleon ($NN$) interaction (based upon $\rho$-$\omega$ mixing, nucleon mass splitting, and phenomenology) that all reproduce the empirical value for the CSB…
Using a purely hadronic model, we study the charge-symmetry-breaking $\rho$-$\omega$, $\sigma$-$\delta$, $\sigma$-$\rho$ and $\delta$-$\omega$ mixing amplitudes in isospin asymmetric nuclear matter. The basic assumption of the model is that…
Contributions of two-pseudoscalar and vector-pseudoscalar meson loops to the rho-omega mass splitting are evaluated in a covariant model based on studies of the Schwinger-Dyson equations of QCD. The role and importance of the different time…
We calculate the momentum dependence of the $\rho-\omega$ mixing amplitude in a purely hadronic model. The basic assumption of the model is that the mixing amplitude is generated by $N{\bar{N}}$ loops and thus driven entirely by the…