相关论文: Vector-meson contributions do not explain the rate…

It has been known for many years that there is a CP-conserving component for the decay mode K_L -> pi0 e+e- and that its magnitude can be obtained from a measurement of the amplitudes in the K_L -> pi0 gamma gamma decay mode. We point out…

An effective theory of large N_{C} QCD of mesons has been used to study six K_{l4} decay modes. It has been found that the matrix elements of the axial-vector current dominate the K_{l4} decays. PCAC is satisfied. A relationship between…

We have studied in the framework of Chiral Perturbation Theory (ChPT) the O(p^6) Vector Meson contributions to K -> pi gamma gamma and K(L) -> gamma gamma^*. We construct the most general ChPT lagrangian for the weak…

We study the long-distance dominated K_L -> pi^+ pi^- gamma decay at O(p^6) in Chiral Perturbation Theory. The complete calculation of the O(p^6) loop magnetic amplitude is carried out. At this chiral order the model dependent part of the…

The decay K_L -> pi0 gamma e+ e- occurs at a it higher rate than the nonradiative process K_L -> pi0 e+ e-, and hence can be a background to CP violation studies using the latter reaction. It also has an interest in its own right in the…

The vector manifestation (VM) is a new pattern for realizing the chiral symmetry in QCD. In the VM, the massless vector meson becomes the chiral partner of pion at the critical point, in contrast with the restoration based on the linear…

We discuss and test the assumptions of the chirally normalized vector meson dominance model (CN-VMD), as it is used for tau decays. We compare the CN-VMD amplitudes with those using on-shell couplings, derived directly from experimental…

The decay $\eta'\rightarrow\pi^0\gamma\gamma$ is studied theoretically in the framework of the Vector Meson Dominance model (VMD). We find theoretically a significant contribution of the interference of $\omega-\rho$ and provide theoretical…

We report on a new measurement of the decay KL -> pi0 gamma gamma by the KTeV experiment at Fermilab. We determine the KL -> pi0 gamma gamma branching ratio to be (1.68 +/- 0.07 +/- 0.08)x10**-6. Our data shows the first evidence for a…

We report on the first observation of the decay KL -> pi0 ee gamma by the KTeV E799 experiment at Fermilab. Based upon a sample of 48 events with an estimated background of 3.6 +/- 1.1 events, we measure the KL -> pi0 ee gamma branching…

We calculate the omega --> pi0 gamma* and phi --> pi0 gamma* electromagnetic transition form factors based on dispersion theory, relying solely on a previous dispersive analysis of the corresponding three-pion decays and the pion vector…

Using a current algebra framework, we discuss the contribution of vector meson exchanges to the CP violating asymmetry in the decay $K^{\pm}\rightarrow\pi^{\pm}\pi^0$, resulting from the interference of the $K\rightarrow\pi\pi$ amplitude…

Using the close relationship between the low--energy constants of chiral perturbation theory and the chiral invariant interactions of the vector meson resonances with the pseudoscalar mesons, we investigate the process $\rho^0 \ra \pi^+…

After describing the SU(2) linear sigma model (L$\sigma$M), we dynamically generate it using the B.W. Lee null tadpole sum (characterizing the true vacuum) together with the dimensional regularization lemma. Next we generate the…

A complete theoretical analysis of the $C$-conserving semileptonic decays $\eta^{(\prime)}\to\pi^0l^+l^-$ and $\eta^\prime\to\eta l^+l^-$ ($l=e$ or $\mu$) is carried out within the framework of the Vector Meson Dominance (VMD) model. An…

The interactions of $\rho$, $K^*$, $\phi$ and $\omega$ vector-mesons with low-momentum $\pi$, $K$ and $\eta$ pseudoscalar mesons are constrained by chiral symmetry. We derive a heavy vector-meson chiral Lagrangian in which the vector mesons…

We derive the the effective lagrangian that describes the interactions among vector, axial-vector mesons and pseudoscalars starting from the extended chiral quark model (ECQM). The results for the low-energy constants of this effective…

Starting from the study of the low-energy and high-energy behaviours of the QCD three-point functions <VAP>, <VVP> and <AAP>, several O(p^6) low-energy constants of the chiral Lagrangian are evaluated within the framework of the lowest…

Recent results by Benayoun et al. comparing the predictions of a range of existing models based on the Vector Meson Dominance hypothesis are summarized and discussed. These are compared with data on e+ e- -> pi+ pi- and e+ e- -> mu+ mu-…

We consider the fidelity of the vector meson dominance (VMD) assumption as an instrument for relating the electromagnetic vector-meson production reaction $e + p \to e^\prime + V + p$ to the purely hadronic process $V + p \to V+p$. Analyses…