Related papers: The process $e^+e^- \to \eta(\eta')2\pi$ in the ex…
Electron-positron annihilations at an average center-of-mass energy of 133 GeV from the four LEP-experiments are presented. This includes in particular the total cross-section and multiplicities, thrust, rapidity and transverse momentum…
The decay widths of $\rho' \to \pi\pi, \omega\pi, \rho\eta$, $\omega' \to \rho\pi, \omega\eta$ and $\pi' \to \rho\pi$ are recalculated within the extended NJL quark model. It is shown that the mass of $\rho'(1450)$ meson in the derived in…
We discuss the processes $\gamma\gamma\to\pi^0\pi^0$ and $\eta\to\pi^0 \gamma\gamma$ at $O(p^6)$ in the momentum expansion. The calculation involves tree--level, one--loop and two--loop diagrams of a chiral effective lagrangian which is…
The cross section of the process $e^+e^-\to \pi^+\pi^-\pi^0$ was measured in the Spherical Neutral Detector (SND) experiment at the VEPP-2M collider in the energy region $\sqrt[]{s}$ below 980 MeV. This measurement was based on about $1.2…
A search for the process $e^+e^- \to \eta^\prime$ has been performed with the SND detector at the VEPP-2000 $e^+e^-$ collider. The data were accumulated at the center-of-mass energy of $957.78\pm 0.06$ MeV with an integrated luminosity of…
We calculate within the Extended Nambu--Jona-Lasinio model the leading in $1/N_c$ contribution to $\gamma\gamma\to\pi^0\pi^0$ to all orders in the external momenta and quark masses. This result is then combined with the known two-loop…
In this work we evaluate the cross section of the process $e^+e^-\to J/\psi \eta_c$ at energy $\sqrt{s}\approx 10.6$ GeV in the Bethe-Salpeter formalism. To simplify our calculation, the heavy quark limit is employed. Without taking the…
The process $e^+e^-\to\eta\pi^0\gamma$ is studied in the center-of-mass energy range 1.05-2.00 GeV using data with an integrated luminosity of 94.5 pb$^{-1}$ collected by the SND detector at the VEPP-2000 $e^+e^-$ collider. The…
Radiative decays of pseudoscalar and vector mesons are calculated in the framework of the chiral Nambu-Jona-Lasinio (NJL) model. We use the amplitude for triangle quark loops of anomalous type. In evaluating these loop integrals we use two…
A search for the rare decay $\eta \rightarrow e^+e^-$ is performed using the inverse process $e^+e^- \rightarrow \eta$ in the decay mode $\eta\to\pi^0\pi^0\pi^0 $. We analyze data with an integrated luminosity of 654 nb$^{-1} $ accumulated…
The process $e^+e^-\to\omega\eta\pi^0$ is studied in the energy range $1.45-2.00$ GeV using data with an integrated luminosity of 33 pb$^{-1}$ accumulated by the SND detector at the $e^+e^-$ collider VEPP-2000. The…
We consider the $\pi^+\pi^-\pi_0\gamma$ final state in electron-positron annihilation at cms energies not far from the threshold. Both initial and final state radiations of the hard photon is considered but without interference between…
The reaction pp -> pf (eta pi pi) ps has been studied at 450 GeV/c. There is clear evidence for an a2(1320)pi decay mode of the eta2(1645) and eta2(1870). In addition, there is evidence for an a0(980)pi$ decay mode of both resonances and an…
We amend a recent dispersive analysis of the anomalous $\eta$ decay process $\eta\to\pi^+\pi^-\gamma$ by the effects of the $a_2$ tensor meson, the lowest-lying resonance that can contribute in the $\pi\eta$ system. While the net effects on…
The production rate for \eta' in pp ->pp \eta' at rest is calculated in a covariant one boson exchange model, previously applied to study pi^0 and \eta production in NN collisions. The transition amplitudes for the elementary BN -> eta' N…
The $e^+e^-\to\eta\gamma$ cross section has been measured in the center-of-mass energy range 1.07--2.00 GeV using the decay mode $\eta\to 3\pi^0$, $\pi^0\to \gamma\gamma$. The analysis is based on 36 pb$^{-1}$ of integrated luminosity…
In this paper, we study the processes of $e^{+}e^{-}$ annihilation into two body final states, either two pseudoscalar mesons or one meson with a photon. The hadronic vacuum polarization form factors are calculated within the framework of…
In the framework of the $U(3) \times U(3)$ extended Nambu-Jona-Lasinio model, the processes $e^+e^- \to K^+K^-\pi^0$ and $e^+e^- \to K^+K^-\eta$ are described taking into account both ground and first radially excited intermediate meson…
The results of the search for the $e^+e^-\to\eta^{\prime}\gamma$ process in the center-of-mass energy range from 1.075 to 2 GeV are presented. We analyze data with an integral luminosity of 746 pb$^{-1}$ accumulated with the SND detector at…
High-energy behavior of R-ratio of electron-positron annihilation into hadrons is studied. In particular, it is argued that at any given order of perturbation theory the re-expansion of the R-ratio in the ultraviolet asymptotic can be…