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A. A. Polunin

Publications and source records attributed to A. A. Polunin.

10 recordsLinked to original sources
arXiv2003

Experimental study of the e+e- -> pi0 gamma process in the energy region sqrt(s)=0.60-0.97 GeV

Results of the study of the e+e-->pi0 gamma process with SND detector at VEPP-2M collider in the c.m.s. energy range sqrt(s)=0.60-0.97 GeV are presented. Using 36513 selected events corresponding to a total integrated luminosity of 3.4 pb^-1 the e+e-->pi0 gamma cross section was measured. The energy dependence of the cross section was analyzed in the framework of the vector meson dominance model. The data are well described by a sum of phi,omega,rho0->pi0 gamma decay contributions with measured decay probabilities: Br(omega->pi0 gamma)=(9.34+-0.15+-0.31)% and Br(rho0->pi0 gamma)=(5.15+-1.16+-0.73)*10^-4 . The rho-omega relative interference phase is phi(rho,omega}=(-10.2+-6.5+-2.5) degree.

hep-ex↗
arXiv2002

Study of the process $e^+e^- \to π^+π^-π^0$ in the energy region $\sqrt[]{s}$ from 0.98 to 1.38 GeV.}

The cross section of the process $e^+e^-\to π^+π^-π^0$ was measured in the Spherical Neutral Detector experiment at the VEPP-2M collider in the energy region $\sqrt[]{s} = 980 ÷1380$ MeV. The measured cross section, together with the $e^+e^-\to π^+π^-π^0$ and $ωπ^+π^-$ cross sections obtained in other experiments, was analyzed in the framework of the generalized vector meson dominance model. It was found that the experimental data can be described by a sum of $ω$, $ϕ$ mesons and two $ω^\prime$ and $ω^{\prime\prime}$ resonances contributions, with masses $m_{ω^\prime}\sim 1490$,$m_{ω^{\prime\prime}}\sim 1790$ MeV and widths $Γ_{ω^\prime}\sim 1210$, $Γ_{ω^{\prime\prime}}\sim 560$ MeV. The analysis of the $π^+π^-$ invariant mass spectra in the energy region $\sqrt[]{s}$ from 1100 to 1380 MeV has shown that for their descriptionone should take into account the $e^+e^-\toωπ^0\toπ^+π^-π^0$ mechanism also. The phase between the amplitudes corresponding to the $e^+e^-\toωπ$ and $e^+e^-\toρπ$ intermediate states was measured for the first time. The value of the phase is close to zero and depends on energy.

hep-ex↗
arXiv2001

Review of experimental results from SND detector

The review of experimental results obtained with SND detector at VEPP-2M $e^+e^-$ collider in the energy region $\sqrt[]{s}=0.36$ -- 1.38 GeV is given. The presented results include the following items: studies of the light vector mesons radiative decays, OZI-rule and G-parity suppressed $ϕ$-meson rare decays, $ϕ$-meson parameters measurements, studies of $e^+e^-\toπ^+π^-π^0$ process dynamics, $η$ and $K_S$ mesons rare decays, $η$ and $ϕ$ mesons conversion decays, and study of the $e^+e^-$ annihilation into hadrons.

hep-ex↗
arXiv2001

Measurements of the parameters of the $ϕ(1020)$ resonance through studies of the processes $e^+e^- \to K^+K^-$, $K_SK_L$ and $π^+π^-π^0$

The cross sections of the processes $e^+e^- \to K^+K^-$, $e^+e^- \to K_SK_L$ and $e^+e^- \to π^+π^-π^0$ were measured in the SND experiment at the VEPP-2M collider in the energy region near the $ϕ(1020)$ meson. These measurements were based on about $10^6$ $K^+K^-$, $0.5 \times 10^6$ $K_SK_L$ and $0.4 \times 10^6$ $π^+π^-π^0$ selected events. Themeasured cross sections have been analyzed in the framework of the vector meson dominance model and the main parameters of the $ϕ$-resonance were obtained, such as its mass, width, the production cross section and branching ratios of the main decay modes. The measured value of the $ϕ$ meson total width, $Γ_ϕ = 4.21 \pm 0.04$ is lower than the present world average of $4.458 \pm 0.032$ MeV. Contributions in addition to the conventional vector meson dominance model were found in the $e^+e^- \to π^+π^-π^0$ reaction cross section.

hep-ex↗
arXiv1999

Observation of the decay PHI(1020)--->OMEGA+PI0

The reaction e^+e^- ---> OMEGA+PI0 ---> PI+PI- 2PI0 has been studied with SND detector at VEPP-2M e^+e^- collider in the vicinity of the PHI(1020) meson resonance. The observed interference pattern in the energy dependence of the cross section is consistent with existence of the decay PHI ---> OMEGA+PI0 with a branching ratio of B(PHI ---> OMEGA+PI0)=(4.8+1.9-1.7+-0.8)x10^{-5}. The real and imaginary parts of the decay amplitude were measured. The PHI ---> OMEGA+PI0 decay was observed for the first time.

hep-ex↗
arXiv1998

Experiments at VEPP-2M with SND detector

Short overview of experiments with SND detector at VEPP-2M e^+e^- collider in the energy range 2E = 400 - 1400 MeV and preliminary results of data analysis are presented.

hep-ex↗
arXiv1997

First Physical Results from SND Detector at VEPP-2M

The paper describes experiments with the SND detector at VEPP-2M collider, carried out during the period from October 1995 until June 1997. The total integrated luminosity of 6.4 pb^{-1} was collected in the energy range 2E=0.4-1.4 GeV (MHAD97 experiment), corresponding to 4*10^5 mu^+ mu^- pairs produced. Preliminary results of the 1996 phi-meson experiment (FI96) are presented. The total number of phi-mesons produced is 4*10^6. New data on rare decays of phi and eta (550) mesons, in particular B(phi -> eta gamma) = (1.30+-0.06+-0.07)%, B(phi -> pi^0 pi^0 gamma) = (1.1+-0.2)*10^{-4}, (M_{pi^0 pi^0} > 800 MeV), B(phi -> f^0 gamma) = (4.7+-1.0)*10^{-4}, B(phi -> eta pi^0 gamma) = (1.3+-0.5)*10^{-4}, B(phi -> eta' gamma) < 1.7*10^{-4}, B(phi -> 2 pi^0 ) < 6*10^{-4} were obtained.

hep-ex↗