Related papers: Forward dispersion relations and Roy equations in …
We show that a suitable setting for comparison of the low-energy representation for pion-pion scattering amplitudes, with dispersive representation for these amplitudes, is provided by certain manifestly crossing symmetric dispersion…
Properties of scalar--isoscalar mesons in a mass range from pi-pi threshold up to 1800 MeV are analysed using an unitary model with separable interactions in three decay channels: pi-pi, K-anti K and an effective 2pi-2pi. Different…
The pion-pion scattering amplitudes provided by second-order chiral perturbation theory are confronted with known rigorous constraints derived from the axioms of quantum field theory. We mainly test constraints restricting the…
We propose a new method to obtain the K -> pi pi amplitude from K -> pi which allows one to fully account for the effects of final state interactions. The method is based on a set of dispersion relations for the K -> pi pi amplitude in…
We impose unitarity constraints on the S-wave isoscalar pion-pion amplitudes extracted from the analysis of the pi- p ---> pi+ pi- n data which have been measured by the CERN-Cracow-Munich collaboration on a transversely polarized target at…
In our talk at Nihon university symposium, we have argued that the pipi / Kpi production amplitudes F generally have different structures from those of the pipi / Kpi scattering amplitudes T from a viewpoint of generalized S matrix on the…
B decays into pion pion K and K anti-K K, where the pion-pion and anti-K K pairs interact in isospin zero S-wave, are studied in the pion-pion effective mass range from threshold to 1.2 GeV. The interplay of strong and weak decay amplitudes…
The problem of scalar mesons still remains a challenging puzzle, for which we do not even know which are the right pieces to set up. The proliferation of resonances (some of them are very broad and appear on top of hadronic thresholds) and…
This is the first of a series of papers devoted to a detailed analysis of isospin-breaking effects in the $\pi \pi$ scattering amplitude and the vector form factor of the pion. Isospin breaking originates from the mass difference between up…
The experimental isoscalar $\pi\pi\to\pi\pi$ S-wave amplitude squared below 1.75 GeV is characterized by a very broad structure $f_0(400-1200)$ with two narrow dips due to its destructive interference with the $f_0(980)$ and $f_0(1500)$.…
A simple Regge pole model for $K\pi$ scattering explains the large $e^{i \delta}$ between isospin amplitudes which is observed at the D meson mass ($\delta \approx \pi/2$). It predicts $\delta \approx 14^{\circ}- 20^{\circ}$ at the B mass.…
Within the framework of dispersion theory, we study the the processes $e^+e^-\to \phi(2170) \to \phi \pi\pi(K\bar{K})$. The strong pion-pion final-state interactions, especially the $K\bar{K}$ coupled channel in the $S$-wave, are taken into…
We model large angle intermediate energy pion-pion scattering by the pQCD two-gluon (2g) exchange contribution and discuss the onset of the dominance of the Glauber-Gribov-Landshoff (GGL) component. The pQCD 2g exchange contribution becomes…
We solve the dispersion relation for the P-wave pi pi amplitude.We discuss the role of the left hand cut vs Castillejo-Dalitz-Dyson (CDD), pole contribution and compare the solution with a generic quark model description. We review the the…
We investigate the determination of the $\sigma$ pole from $\pi\pi$ scattering data below the $K\bar{K}$ threshold, including the new precise results obtained from $K_{e4}$ decay by NA48/2 Collaboration. We discuss also the experimental…
In a recent paper by Xiu-Li Gao, Zhi-Hui Guo, Zhiguang Xiao, and Zhi-Yong Zhou, Phys. Rev. D 105, 094002 (2022), here referred to as I, $S$-wave $\pi\pi$ scattering phase shifts obtained in a lattice-QCD calculation are analyzed using…
After summarizing the current theoretical status of the four-body decay B --> K^*(--> K pi) mu^+ mu^-, we apply the formalism of spin-symmetries to the full angular distribution, including the S-wave part involving a broad scalar resonance…
We perform a dispersive theoretical study of the reaction \gamma\gamma\to pi^0\pi^0 emphasizing the low energy region. The large source of theoretical uncertainty to calculate the \gamma\gamma\to\pi^0\pi^0 total cross section for…
We have performed two analytical pipi phase shift analyses using a Standard amplitude analysis of the CERN data on pi(-)p->pi(-)pi(+)n on polarized target at 17.2 GeV/c and a more recent analysis of the same data using Spin Mixing Mechanism…
We discuss the simultaneous dispersive analyses of $\pi K\to \pi K$ and $\pi \pi \to K \bar{K}$ scattering data and the $\kappa/K^*_0(700)$ resonance. The unprecedented statistics of present and future Hadron Experiments, modern Lattice QCD…