$\omega-\rho$ Mixing and the $\omega\to\pi\pi\gamma$ Decay

It is shown, in a model independent way, that the large difference in rho and omega widths gives rise to a new source of momentum dependence for the rho-omega mixing matrix element. The q^2 dependence arising due to the meson widths leads to a significant alteration of the result obtained in the zero-width approximation usually discussed in the literature. The origin of this strong momentum dependence lies in the difference between the rho and omega meson widths.

The direct CP asymmetry in the weak decay process of hadrons is commonly attributed to the weak phase of the CKM matrix and the indeterminate strong phase. We propose a way of creating a strong phase difference between two decay paths involving vector mesons $V= \omega,\rho$ decaying to $\pi^{+}\pi^{-}\pi^{0}$ considering the G-parity suppressed decay process $\rho^{0} \rightarrow \pi^{+}\pi^{-}\pi^{0} $. It can lead to a significant CP asymmetry in the interference region. W...

We determine the value of the \omega -\rho- \pi mesons coupling (g_{\omega\rho\pi}), in the context of the vector meson dominance model, from radiative decays, the \omega \rightarrow 3\pi decay width and the e^+e^- \rightarrow 3\pi cross section. For the last two observables we consider the effect of either a heavier resonance (\rho'(1450)) or a contact term. A weighted average of the results from the set of observables yields g_{\omega\rho\pi} =14.7 \pm 0.1 GeV^{-1} in absen...

In the present work, the mixing angle of the vector $\omega(782)$ and $\phi(1020)$ mesons is estimated in the framework of Nambu--Jona-Lasinio model. The decay $\phi \to \pi^{0} \gamma$ is considered as a basic process to determine this angle. The obtained value is compared with the results of the other authors. Besides, the width of the decay $\phi \to 3\pi$ and the cross-section of the process $e^{+}e^{-} \to \pi^{0} \phi$ are calculated by using this angle.

It is shown that the relative sign between the $NN\omega$ and $\pi\rho\omega$ coupling constants can be determined most sensitively from $\omega$ production processes in $NN$ collisions. Recent data on these reactions clearly favor the sign of the $\pi\rho\omega$ coupling constant which is opposite to that inferred from studies of the photoproduction reaction in combination with the vector meson dominance assumption and used by many authors. Implication of this finding in the...

The suggestion of momentum dependence in the amplitude for rho-omega mixing has generated concern over related implications for vector meson dominance and the photon-rho coupling. We discuss two established representations of vector meson dominance and show that one of these is completely consistent with such a coupling. We then apply it to a calculation of the pion electromagnetic form-factor. Our analysis leads to a new value for the on-shell rho-omega mixing amplitude of (...

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 quark fields naturally leads to the $\rho^0-\omega$ mixing vertices, and this mixing is entirely from the quark loop in this theory. The off-shell behaviour of the mixing amplitude is analyzed. The on-shell mixing amplitude is obtained from ...

Mixed Propagator (MP) approach to $\rho-\omega$ mixing is discussed. It is found that under the pole-approximation assumption the results of MP approach is not compatible both with the effective Lagrangian theory and with the experiment measurement criterion. To overcome these inconsistent, we propose a new MP approach in which the physical states of $\rho$ and $\omega$ are determined by the requirement of experimental measurement to meson resonance. In terms of this new MP a...

We examine the radiative omega pi0etagamma and rho pi0etagamma decays in a phenomenological framework. We consider the VMD mechanism, chiral loops, intermediate a0-meson and rho−omega mixing. We find the values of the decay width coming from the different amplitudes and compare the results with other studies. We observe that a0-meson intermediate state is very important in the case of the rho pi0etagamma decay and small in the other case for which VMD contribution is do...

The mixing between nonstrange and strange quark wavefunctions in the $\omega$ and $\phi$ mesons leads to a small predicted branching ratio $\b(D_s^+ \to \omega e^+ \nu_e) = {\cal O}(10^{-4})(\delta/3.34^\circ)^2$, where $\delta$ is the mixing angle. The value $\delta = -3.34^\circ$ is obtained in a mass-independent analysis, while a mass-dependent analysis gives $\delta = -0.45^\circ$ at $m(\omega)$ and $-4.64^\circ$ at $m(\phi)$. Measurement of this branching ratio thus can ...