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I. N. Nesterenko

Publications and source records attributed to I. N. Nesterenko.

15 recordsLinked to original sources
arXiv2013

Study of e+e- --> omega pi0 --> pi0 pi0 gamma in the energy range 1.05--2.00 GeV with SND

The cross section for the process e+e- --> omega pi0 --> pi0 pi0 gamma has been measured in the energy range 1.05--2.00 GeV. The experiment has been performed at the e+e- collider VEPP-2000 with the SND detector. The measured e+e- --> omega pi0 cross section above 1.4 GeV is the most accurate to date. Below 1.4 GeV our data are in good agreement with the previous SND and CMD-2 measurements. Data on the e+e- --> omega pi0 cross section are well described by the VMD model with two excited rho-like states. From the measured cross section we have extracted the gamma^* --> omega pi0 transition form factor. It has been found that the VDM model cannot describe simultaneously our data and data obtained from the omega --> pi0 mu+ mu- decay. We have also tested CVC hypothesis comparing our results on the e+e- --> omega pi0 cross section with data on the tau- --> omega pi- nu_{tau} decay.

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

Direct measurement of the phi(1020) leptonic branching ratio

The process e+e-->mu+mu- has been studied by SND detector at VEPP-2M e+e- collider in the phi(1020)-resonance energy region. The measured effective phi meson leptonic branching ratio: B(phi->l+l-)=sqrt{B(phi->e+e-)*B(phi->mu+mu-)}=(2.89+-0.10+-0.06)*10^{-4} agrees well with the PDG value B(phi->e+e-)=(2.91+-0.07)*10^{-4} confirming mu-e universality. Without additional assumption of mu-e universality the branching ratio B(phi->mu+mu-)=(2.87+-0.20+-0.14)*10^{-4} was obtained.

hep-ex↗
arXiv2000

The process $e^+e^-\toωπ^0\toπ^0π^0γ$ up to 1.4 GeV

The cross section of the $e^+e^-\toωπ^0\toπ^0π^0γ$ 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 $ρ$, $ρ^{\prime}$ and $ρ^{\prime\prime}$ contributions are presented.

hep-ex↗
arXiv1999

Upper limit on the Ks ---> 3 pi0 decay

The search for CP-violating K_S\to3π^0 decay was performed with SND detector at VEPP-2M e^+e^- collider. The total amount of data corresponding to 7 million produced K_S mesons was analyzed. No candidate events were found, giving an upper limit of the decay branching ratio: Br(K_S\to3π^0) < 1.4\cdot10^{-5} at 90% confidence level.

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↗