Radiative Decays Of Light Mesons

Content: Radiative decays of light mesons are important aspects in low-energy hadronic physics, through which structures and properties of light mesons can be revealed. The fundamental theory of hadronic interactions——quantum chromodynamics(QCD), is very effective in dealing with various processes in high energy by application of perturbertive methods. But in low energy scale, in which non-perturbertive parts dominate, the perturbertive methods fail. To explore low-energy haronic physics, many models, such as dispersion relations, chiral models and vector meson dominance (VMD) models, are adopted.In view of effective theories, the radiative decays of light mesons involve mainly interactions between photons and hadrons. The vector meson dominance models can handle electromagnetic interaction of hadrons successfully. In this paper, with the newest experimental data, we explore the radiative decays of light mesons by using vector meson dominance models in SU(3) symmetry context.In this paper, first we define the SU(3) nonets of pseudoscalar mesons and vector mesons. According to the effective Lagrangian given by SU(3) symmetry , we calculate the relation of coupling constant gV Pγof SU(3) nonets. Then by consideringω-φmixing andη-η' mixing, we give the relation of coupling constant gV Pγin physical states context. Finally we give the theoretic values of V→Pγdecay widths and compare them with experiments. In the second part of this work, using VMD models, we convert coupling constant gV Pγinto coupling constant gV PV. With the results of decays of a light meson into a electron and a positron, we obtain vector meson mixing angleθV = 41.9°,and coupling constants between photon and hadronγρ= 2.524andγY= 0.924。Using these data, finally we give the theoretic values of V→Pγdecay widths again and compare them with experiments.