Электромагнитные формфакторы протона являются важнейшим источником наших знаний о его внутренней структуре. Два различных метода измерения этих формфакторов, метод Розенблюта и метод передачи поляризации, дают противоречивые результаты. Предполагается, что это противоречие может быть устранено при учете жесткой части вклада двухфотонного обмена в сечение упругого -рассеяния. Этот вклад может быть измерен экспериментально, путем прецизионного сравнения сечений упругого рассеяния позитронов и электронов на протонах. В настоящей работе описано такое измерение, проведенное на накопительном кольце ВЭПП-3, Новосибирск, при двух энергиях пучка, и ГэВ, и углах рассеяния позитронов/электронов , в первом случае и во втором случае. Приводятся предварительные результаты эксперимента и их сравнение с теоретическими предсказаниями.

Proton electromagnetic form factors are among the most important sources of information about the internal structure of the proton. Two different methods for measuring these form factors, the method proposed by Rosenbluth and the polarization-transfer method, yield contradictory results. It is assumed that this contradiction can be removed upon taking into account the hard part of the contribution of two-photon exchange to the cross section for elastic electron-proton scattering. This contribution can measured experimentally via a precision comparison of the cross sections for the elastic scattering of positrons and electrons on protons. Such a measurement, performed at the VEPP-3 storage ring in Novosibirsk at the beam energies of 1.6 and 1.0 GeV for positron (electron) scattering angles in the ranges of θ e = 15°–25° and 55°–75° in the first case and in the range of θ e = 65°–105° in the second case is described in the present article. Preliminary results of this experiment and their comparison with theoretical predictions are described.

At BINP the construction of the tagging system for almost-real photons (TS) is in progress. The energy of tagging photons can be up to 1.5 GeV. The projected energy resolution of TS is better then 1%. For at least a half of photons the linear polarization can be determined. The tagging system will extend the possibilities for photoreaction studying at VEPP-3 significantly. TS would allow to perform a complete kinematics reconstruction, thus permitting a reliable rejection of the background processes; to extend the measurements to higher photon energy; to enabling Σ-asymmetry measurements and double polarization experiments.

The VEPP-2000 electron-positron collider was commissioned in 2010. About 60 pb-1 were collected so far by CMD-3 detector in the whole available c.m. energy range from 0.32 GeV to 2.0 GeV. The preliminary results of data analysis for various modes of e+e− → hadrons are discussed.

We report preliminary results on the measurement of the e + e -→ K + K -π + π -cross section in the c. m. energy range from 1.5 GeV to 2 GeV.It was found that the cross section is dominated by the contributions of the K + K -ρ, K * Kπ, φ π + π -and K * K * intermediate states.

We describe a precise measurement of the ratio of the ( e + p ) to ( e − p ) elastic scattering cross sections. This comparison is sensitive to the effect of two-photon exchange contributions which may be the cause for inconsistent extractions of the proton form factors obtained using different methods. The experiment was performed at storage ring VEPP–3, Novosibirsk at energies of positron/electron beams of 1.0 and 1.6 GeV with electron/positron scattering angles θ = 65÷105° for the first case and 15÷25° and 55÷75° for the second case. Details of the experiment and the preliminary results are presented.

Since 2010 the CMD-3 detector has been collecting data at the e+e− collider VEPP-2000 at Budker Institute of Nuclear Physics. CMD-3 is a general purpose detector designed to study e+e− annihilation into hadrons in the wide energy range √s = 0.3−2GeV. The barrel electromagnetic calorimeter of the detector has a thickness equal to 13.5X0 and consists of two subsystems: closest to the beam pipe is the Liquid Xenon calorimeter (LXe) and the outer one is based on CsI scintillation crystals (CsI). The design of the LXe calorimeter and its current performance are presented.

During years 2011 and 2012 data taking runs have been carried out at VEPP-2000 e+e- collider to measure the production of the nucleon-antinucleon pairs [Formula: see text] near threshold. In this talk the preliminary results on the nucleon timelike electromagnetic form factors (FF) and the |GE/GM| ratio are presented.

We report preliminary results on the measurement of the [Formula: see text] cross section with the CMD-3 detector at the VEPP-2000 electron-positron collider based on 4.5 pb-1 of integrated luminosity collected in the c.m. energy range 1.92 - 2.0 GeV. Event selection using information from the Drift Chamber and Calorimeters provides a clean sample of [Formula: see text] events. The obtained results are in good agreement with the previous measurements.

The cross section of the process e+e−→3(π+π−) has been measured using a data sample of 22pb−1 collected with the CMD-3 detector at the VEPP-2000 e+e− collider. 7956 signal events are selected in the center-of-mass energy range 1.5–2.0 GeV. The measured cross section exhibits a sharp drop near the pp¯ threshold. A first study of dynamics of six-pion production has been performed.

The decay phi --> eta'gamma has been observed by the CMD-2 detector at the e(+)e(-) collider VEPP-2M at Novosibirsk. Of 5.5 million produced phi's, six events of the phi --> eta'gamma decay were selected with the expected background less than one event. The corresponding branching ratio is B(phi --> eta'gamma) = 1.2(-0.5)(+0.7).10(-4). It is the first observation of this radiative decay. (C) 1997 Published by Elsevier Science B.V.

The first results of the luminosity measurement with the CMD-3 detector at the VEPP-2000 e+e− collider are presented. The luminosity was measured using two different processes e+e−→e+e− and e+e−→γγ, that allowed to better understand and estimate the systematic accuracy which was found to be ∼2%. The analysis of the data was done on the integrated luminosity about 20 pb−1. A Monte-Carlo Generator Photon Jets (MCGPJ) [A.Arbuzov et al., EPJ C46, 689 (2006); S.Actis et al., EPJ C66, 585 (2010)] to simulate Bhabha scattering events as well as production of two photons was adopted for analysis of the data. A theoretical precision of these cross sections with radiative corrections (RC) is estimated to be better than 0.2%.

Gennady Nikolaevich Kulipanov, Deputy Director of Budker Institute of Nuclear Physics of the Siberian Branch of the Russian Academy of Sciences (RAS) and Director of the Siberian Synchrotron and Terahertz Radiation Centre, Full Member of the RAS, celebrated his 70th birthday on January 25, 2012.

Two e+e− colliders, VEPP-4M and VEPP2000, are taking data at the Budker INP in Novosibirsk, Russia. KEDR detector at the VEPP-4M collider continues deliver precision measurements of the charmonium family. Results of the ψ(2S ) and ψ(3770) study are presented. Two energy scans of a center-of-mass energy range from 1 GeV to 2 GeV has been performed by the VEPP2000 collider with an integrated luminosity of about 35 pb−1, collected by each of the CMD-3 and SND detectors. This paper reports the latest results from VEPP-2000 obtained by the CMD-3 collaboration.

The phi(1020) meson leptonic width has been determined from the combined analysis of 4 major decay modes of the resonance (phi > K+K-, (KLKS0)-K-0, pi(+)pi(-)pi(0), eta gamma) studied with the CMD-2 detector at the VEPP-2M e(+)e(-) collider. The following value has been obtained: Gamma(phi -> e(+)e(-)) = 1.235 +/- 0.006 +/- 0.022 keV. The phi(1020) meson parameters in four main decay channels have been also recalculated: B(phi -> K+K-) = 0.493 +/- 0.003 +/- 0.007, B(phi -> K-L K-S) = 0.336 +/- 0.002 +/- 0.006, B(phi -> pi(+)pi(-)pi(0)) = 0.155 +/- 0.002 +/- 0.005, B(phi -> eta gamma)= 0.0138 +/- 0.0002 +/- 0.0002. (C) 2010 Elsevier B.V. All rights reserved.

Nikolai Sergeevich Dikansky (on his 70th birthday), Lev M Barkov, A E Bondar', Gennadii I Dimov, E P Kruglyakov, Gennadii N Kulipanov, Vasilii V Parkhomchuk, D V Pestrikov, Aleksandr N Skrinsky, Iosif B Khriplovich, Yuriy M Shatunov