Related papers: Finding the sigma pole by analytic extrapolation o…

We report our progress on the data analysis of $\pi\pi$ scattering data in terms of Forward Dispersion Relations (FDR), as well as Roy equations (RE) and their once-subtracted counterpart, GKPY equations. The first part of the analysis…

We present an extraction of the pion-nucleon ($\pi N$) scattering lengths from low-energy $\pi N$ scattering, by fitting a representation based on Roy-Steiner equations to the low-energy data base. We show that the resulting values confirm…

Pion-kaon ($\pi K$) pairs occur frequently as final states in heavy-particle decays. A consistent treatment of $\pi K$ scattering and production amplitudes over a wide energy range is therefore mandatory for multiple applications: in…

The Compton scattering on a charged pion is studied using the dispersion relations. Unknown mass, full width and decay width into \gamma \gamma of the sigma meson are found from a fit to the experimental data for the process \gamma+\gamma…

We use the Belle data on the $K^- p$ mass distribution of the $\Lambda_c^+ \to p K^- \pi^+$ reaction near the $\eta \Lambda$ threshold to determine the $\eta \Lambda $ scattering length and effective range. We show that from these data…

We review our analysis of $\pi K$ scattering using forward dispersion relations. The method yields a set of simple parameterizations that are compatible with forward dispersion relations up to 1.6 GeV while still describing the data. Once…

Re-analyzing the old phase shift data of I=0, \pi\pi (I=1/2, K\pi) scattering, we show an evidence for existence of the \sigma-particle (\kappa-particle) with a comparatively light mass, which has been missing for a long time: In the…

We provide new global parametrizations of $\pi\pi \to \pi\pi$ scattering for the S2, P, D, F, and G partial waves up to at least 1.8 GeV, easy to implement for phenomenological use. With earlier S0-wave parametrizations, slightly updated…

Using unitarized Chiral Perturbation Theory methods, we perform a detailed analysis of the $\pi\pi$ scattering poles $f_0(600)$ and $\rho(770)$ behaviour when medium effects such as temperature or density drive the system towards Chiral…

In this talk I summarize a recently proposed mechanism to understand pi pi scattering to 1 GeV. The model is motivated by the 1/Nc expansion to QCD, and includes a current algebra contact term and resonant pole exchanges. Chiral symmetry…

We demonstrate that dispersion theory allows one to deduce crucial information on $\pi\eta$ scattering from the final-state interactions of the light mesons visible in the spectral distributions of the decays $\bar{B}^0_d \to…

We present a new method for the determination of the pion-pion scattering lenght combination a0-a2, based on the study of the pi0-pi0 spectrum in K->pi+ pi0 pi0 in the vicinity of the pi+ pi- threshold. The method requires a minimum of…

The generalized linear sigma model for mixing among two- and four-quark components of scalar (and psedudosclar) mesons below and above 1 GeV is applied to the $\pi\eta$ channel in which the isovector scalars $a_0(980)$ and $a_0(1450)$ are…

It is shown that the linear correlation relates the S-wave phase shifts from the threshold up to dipion mass 900 MeV. By using this correlation at the solution of the Roy equations, the accuracy of determination of S-wave lengths is…

We review the use of new and precise dispersive equations, which also implement crossing symmetry, in order to shed further light on the long-standing puzzle in the parameters of the f0(500), as well as the f0(980). This puzzle is finally…

A combined fit is made to E791 data on D->K-pi-pi, LASS data on K-pi elastic scattering, and BES II data on J/Psi->K*(890)-K-pi.In all cases, the K-pi S-wave is fitted well with a kappa resonance and Ko(1430); the kappa requires an…

We provide a precise, model- and parametrization-independent dispersive determination of the $f_0(500)$, $\rho(770)$, $f_0(980)$, $f_2(1270)$, $f_0(1370)$, $\rho(1450)$, $f_0(1500)$, and $\rho_3(1690)$ resonance pole parameters. They are…

We present preliminary results of an improved pion-pion scattering dispersive analysis that includes: a refined treatment of inelasticities, the introduction of G-waves, the extension of Forward Dispersion Relations as constraints up to 1.6…

The evidences for sigma(600) and kappa(900) observed in our analyses on the pi pi and K pi scattering phase shift data are described, briefly. The analysis have been performed by the interfering amplitude method, which satisfies the…

Phase shifts for $s$-wave $\pi\pi$ scattering in both the $I=0$ and $I=2$ channels are determined from a lattice QCD calculation performed on 741 gauge configurations obeying G-parity boundary conditions with a physical pion mass and…