Related papers: Sigma Signal for Hybrid Baryon Decay
The $\sigma$ resonance was observed as a conspicuous $\pi^+\pi^-$ peak in hadronic decays like $J/\psi\to \pi^+\pi^-\omega$ or $D^+\to\pi^+\pi^-\pi^+$. The phase of the $\sigma\to\pi^+\pi^-$ amplitude, extracted from production data within…
We estimate the relative branching ratio of $\sigma$ to 2$\pi$ for the decay of the $\Psi'(2S)$, which we have found to be a mixed charm and hybrid charmonium meson. The external field method and correlators from a previous calculation are…
We examine the mixing between the sigma meson $\sigma$ and the "pure" glueball field $H$ and study the decays of the scalar glueball candidate $f_0(1500)$ (a linear combination of $\sigma$ and $H$) into two and four pions in effective…
Recently the D$^+$ charm meson was observed to have a clear branching ratio into the low energy $\pi-\pi$ sigma resonance, while this channel was not detected in the D$_s^+$ decay. It is shown that this is consistent with the standard…
We analyse data on pi pi and gamma gamma scattering below 700 MeV within an improved analytic K-matrix model. This model is based on an effective theory with couplings between resonances, hadrons and photons. The two-photon decay of a…
We estimate the I=0 scalar meson sigma/f_0(600) parameters from pi-pi and gamma-gamma scattering data below 700 MeV using an improved analytic K-matrix model. A fit of the hadronic data gives a complex pole mass M_sigma= 422-i290 MeV, while…
We study the radiative $\rho^0\to \pi^+\pi^-\gamma$ and $\rho^0\to \pi^0\pi^0\gamma$ decays and we calculate their branching ratios using a phenomenological approach by adding to the amplitude calculated within the framework of chiral…
The experimental branching ratio for the radiative decay $\rho^{0}\to\pi^{+}+\pi^{-}+\gamma$ is used to estimate the coupling constant $g_{\rho\sigma\gamma}$ for a set of values of $\sigma$-meson parameters M$_{\sigma}$ and…
The importance of resonances for the radiative hyperon decays is examined in the framework of chiral perturbation theory. Low lying baryon resonances are included into the effective theory and tree contributions to these decays are…
The experimental results obtained in the last few years on kaon decays (K$\to2\pi$ and, above all, Ke4 decays) allow a reliable, model independent determination of low energy $\pi\pi$ scattering in the S0 wave. Using them and, eventually,…
A prediction for the contributions of chiral loops and the L$\sigma$M model to the radiative $\phi\to\pi^0\eta\gamma$ decay mode is presented. The L$\sigma$M is used as an appropriate framework for describing the pole effects of the…
In an attempt to explain the latest experimental result about the branching ratio of $\omega\to \pi^0\pi^0\gamma$ decay we reexamine the decay mechanism of this decay in a phenomenological framework in which the contributions of VMD, chiral…
Among the light baryons, the $J^\pi = \frac{1}{2}^-$ $\Lambda(1405)$ hyperon is an important special case as it sits just below the $N\bar{K}$ threshold and decays almost exclusively to $\Sigma\pi$. Some long-standing hypotheses for…
We report on measurements of the inclusive production rate of Sigma+ and Sigma0 baryons in hadronic Z decays collected with the L3 detector at LEP. The Sigma+ baryons are detected through the decay Sigma+ -> p pi0, while the Sigma0 baryons…
We investigate the two-body decay modes $\rho\rho, \pi\pi^{\ast}(1300)$ and $\sigma \sigma$ of the $f_0(1500)$, all leading to the $4\pi$ decay channel, in a three-state mixing scheme, where the $f_0(1500)$ is a mixture of the lowest-lying…
We discuss the mixing between the sigma meson sigma and the "pure" glueball field H and study the decays of the scalar glueball candidates f_0(1370), f_0(1500) and f_0(1710) (a linear combination of sigma and H) into two pions in an…
We analyze the mixing between $\Sigma^0$ and $\Lambda^0$ based on the baryon masses. We distinguish the contributions from QCD and QED in the baryon mass splittings. We find that the mixing angle between $\Sigma^0$ and $\Lambda^0$ is…
We calculate the branching ratio of omega --> pi^+ pi^- gamma decay in a phenomenological framework in which the contributions of VMD, chiral loops, sigma-meson intermediate state amplitudes and the effects of omega-rho mixing are…
The ratios of partial widths for the decay of a glueball into two pseudoscalar mesons are calculated under the assumption that the production of light quark pairs ($u\bar u,d\bar d,s\bar s$) in soft gluon-\-induced reactions goes on within…
We study the $\omega\to\pi\pi\gamma$ decays by adding to the amplitude calculated within the framework of chiral perturbation theory and vector meson dominance the amplitude of $\sigma$-meson intermediate state. We estimate the coupling…