Related papers: Interference in the reaction $e^+e^-\to\gamma\pi^+…

Radiative decays \phi\to\eta\pi^0\gamma and \phi\to\pi^0\pi^0\gamma are studied assuming that these decays are caused through the intermediate a_0(980)\gamma and f_0(980)\gamma states, respectively. Fitting the experimental data of the…

The final state interactions of pions in decays $K^\pm\to\pi^\pm\pi^0\pi^0$ are considered using the methods of quantum mechanics. We show how to incorporate the electromagnetic effects in the amplitudes of these decays and to work out the…

I present the calculation of the $\pi^+\gamma^\star\to\pi^+\pi^0$ transition amplitude from quantum chromodynamics performed by the Hadron Spectrum Collaboration. The amplitude is determined for a range of values of the photon virtuality…

The $\gamma\gamma\to\pi\pi$ reactions are discussed. To describe those processes, we include dipion continuum, resonances, high-energy pion-pion rescatterings, $\rho$ meson exchange and pQCD Brodsky-Lepage mechanisms. The cross section for…

We are presenting here the new formulae for Bose-Einstein correlations (BEC) which contain effects of final state interactions (FSI) of both strong (in $s$-wave) and electromagnetic origin. We demonstrate the importance of FSI in BEC by…

We make a theoretical study of the charge and forward-backward pion asymmetries in the e+e- --> pi+ pi- gamma process on and off the phi resonance energy. These observables are rather sensitive to the inner details of the theoretical models…

The process e^+e^-\to\pi^0\gamma in the energy range \sqrt{s}=0.60-1.06 GeV was studied at VEPP-2M collider with SND detector using 14 pb^{-1} of integrated luminosity. Data were analyzed in the framework of the vector meson dominance…

The chromo-polarizability of a quarkonium state is a measure of the amplitude of the $E1$-$E1$ chromo-electric interaction of the quarkonium with soft gluon fields and can be measured in the heavy quarkonium decays. Based on the chiral…

Final state interactions in the $S$--wave $\pi\pi$ system (I=0,2) are re-examined on the basis of the Omn\`es-Mus\-khe\-li\-shvili equation and the coupled channel formalism. The contributions to the pion scalar form factor from $\rho$ and…

We study the processes e+e- --> K+ K- pi+pi-gamma, K+ K- pi0pi0gamma, and K+ K- K+ K-gamma, where the photon is radiated from the initial state. About 84000, 8000, and 4200 fully reconstructed events, respectively, are selected from 454…

We investigate the production of $\phi(2170)$ state in the $e^+e^- \to \phi \pi^+\pi^-$ reaction with the effective Lagrangian approach. In addition to the tree level contributions from the $\phi(1680)$ meson and a possible X(1750) state,…

The cross section of the $e^+e^-\to\omega\pi^0\to\pi^0\pi^0\gamma$ reaction was measured by the SND detector at VEPP-2M $e^+e^-$ collider in the energy range from threshold up to 1.4 GeV. Results of the cross section fitting by the sum of…

We critically analyze recent attempts to include final state interaction (FSI) effects in the calculation of the CP violating ratio epsilon'/epsilon. In particular the approach of using the Muskhelishvili-Omnes equation for the decay…

The amplitude for the anomalous transitions gamma pi(+) -> pi(0) pi(+) is analyzed within Chiral Perturbation Theory including electromagnetic interactions. The presence of a t-channel one-photon exchange contribution induces sizeable e^2…

A procedure is proposed which accounts for final state interaction corrections for near threshold meson production in nucleon-nucleon scattering. In analogy with the Watson-Migdal approximation, it is shown that in the limit of extremely…

We study the processes $e^+e^-\to\pi^+\pi^-\pi^0\pi^0\pi^0\pi^0\gamma$ and $e^+e^-\to\pi^+\pi^-\pi^0\pi^0\pi^0\eta\gamma$ in which an energetic photon is radiated from the initial state. The data were collected with the BaBar detector at…

Differential cross sections of the reactions $(\gamma,\pi^\circ\pi^\circ)$ and $(\gamma,\pi^\circ\pi^++\pi^\circ\pi^-)$ have been measured for several nuclei ($^1$H,$^{12}$C, and $^{\rm nat}$Pb) at an incident-photon energy of…

The phases of terms of amplitude that arise from the $\pi\pi$ interaction are obtained by using a simple realistic model of $\pi\pi$ interaction via virtual $\rho$-meson, instead of the ChPT. It is shown that the standard ChPT approach…

We investigate the discovery potential of the $a_1(1260)$ photoproduction in the $\gamma p \to a_1(1260)^+ n$ and $\gamma p \to \pi^+\pi^+\pi^- n$ reactions via the $\pi$-exchange mechanism. For the $\gamma p \to \pi^+\pi^+\pi^- n$…

The processes $e^+e^-\to e^+e^-X$, with $X$ being either the $\eta$ meson or $\pi^0\pi^0$, are studied at DA$\Phi$NE, with $e^+e^-$ beams colliding at $\sqrt{s}\simeq1$ GeV, below the $\phi$ resonance peak. The data sample is from an…