相关论文: Can parameters of f_0-mesons be determined correct…
Peculiarities of obtaining parameters for broad multi-channel resonances from data are discussed analyzing the experimental data on processes $\pi\pi\to\pi\pi,K\bar{K}$ in the $I^GJ^{PC}=0^+0^{++}$ channel in a model-independent approach…
We present a coupled channel partial wave analysis of nondiffractive S-wave pi+ pi- and K+ K- photoproduction focusing on the KK threshold. Final state interactions are included. We calculate total cross sections, angular and effective mass…
A combined analysis of data on isoscalar S-wave processes $\pi\pi\to\pi\pi,K\overline{K},\eta\eta$ and on decays $J/\psi\to\phi\pi\pi,\phi K\overline{K}$ from the DM2, Mark III and BESIII collaborations is performed to study $f_0$ mesons.…
In a multi-channel $S$-matrix approach, data on $\pi\pi\to\pi\pi,K\bar{K},\eta\eta$ in the $I^GJ^{PC}=0^+2^{++}$ sector and $\pi\pi$ scattering in the $1^+3^{--}$ sector are analyzed to study the $f_2$- and $\rho_3$-mesons, respectively.…
We revisit the recently proposed method for the determination of the pi-pi scattering length combination a_{0}-a_{2}, based on the study of the pi0 pi0 spectrum in K+ -> pi+ pi0 pi0. In view of a precision measurement, we discuss here the…
The Compton scattering on a charged pion and the process \gamma\gamma \to \pi^0\pi^0 are studied using the dispersion relations. Unknown parameters of the S-wave \pi\pi interaction, represented as a board Breit-Wignar resonance, and a sum…
Properties of scalar-isoscalar mesons are analysed using separable interactions in three decay channels: pion-pion, kaon-antikaon and an effective 2pion-2pion. We obtain different solutions by fitting various data on the pion-pion and…
In a combined analysis of the experimental data on the coupled processes $\pi\pi\to\pi\pi,K\bar{K}$ in the channel with $I^GJ^{PC}=0^+0^{++}$, the various scenarios of these reactions (with different numbers of resonances) are considered.…
We evaluate the matrix elements for the processes pi^0 K^0 -> pi^0 K^0 and pi^- K^+ -> pi^0 K^0 in the presence of isospin breaking terms at leading and next-to-leading order. As a direct application the releveant combination of the S-wave…
The effect of isoscalar S-wave multi-channel pion-pion scattering ($\pi\pi\to\pi\pi,K\bar{K},\eta\eta$) is considered in the analysis of data on decays of the $\Upsilon$-meson family -- $\Upsilon(2S)\to\Upsilon(1S)\pi\pi$,…
In this talk we discuss the relevance of dispersive methods and their different applications to obtain simple but rigorous parameterizations of pion-pion and kaon-pion scattering. We show as an example our latest dispersive analysis of $\pi…
Studies on the IJ=00 $\pi\pi$ and $K\bar K$ coupled--channel system are made using newly derived dispersion relations between the phase shifts and poles and cuts. It is found that the $\sigma$ resonance must be introduced to explain the…
A simultaneous analysis (in the model-independent approach) of the $\pi\pi$ scattering (from the threshold to 1.9 GeV) and of the $\pi\pi\to K\overline{K}$ process (from the threshold to $\sim$ 1.46 GeV) is carried out in channel with…
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…
Pion pion scattering is studied in a generalized linear sigma model which contains two scalar nonets (one of quark-antiquark type and the other of diquark-antidiquark type) and two corresponding pseudoscalar nonets. An interesting feature…
We present results of a new multichannel partial-wave analysis for \pi N scattering in the c.m. energy range 1080 to 2100 MeV. This work explicitly includes \eta N and K \Lambda channels and the single pion photoproduction channel.…
The analytic properties of scattering amplitudes provide important information. Besides the cuts, the poles and zeros on the different Riemann sheets determine the global behavior of the amplitude on the physical axis. Pole positions and…
The multichannel S- and P-wave amplitudes for the pion-pion scattering, constructed requiring analyticity and unitarity of the S-matrix and using the uniformization procedure, are elaborated using the dispersion relations with imposed…
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…
We derive a method to calculate the multi-channel K matrix applicable to a broad class of models in which mesons linearly couple to the quark core. The method is used to calculate pion scattering amplitudes in the energy region of low-lying…