ISSN 1063-7761, Journal of Experimental and Theoretical Physics, 2011, Vol. 113, No. 2, pp. 213–220. © Pleiades Publishing, Inc., 2011. Original Russian Text © D.E. Berkaev, D.B. Shwartz, P.Yu. Shatunov, Yu.A. Rogovskii, A.L. Romanov, I.A. Koop, Yu.M. Shatunov, I.M. Zemlyanskii, A.P. Lysenko, E.A. Perevedentsev, A.S. Stankevich, A.I. Senchenko, B.I. Khazin, A.V. Anisenkov, S.E. Gayazov, A.N. Kozyrev, A.E. Ryzhenenkov, D.N. Shemyakin, L.B. Epshtein, S.I. Serednyakov, P.M. Astigeevich, D.P. Kovrizhin, K.A. Martin, A.E. Obrazovskii, I.K. Surin, L.V. Kardapoltsev, O.V. Belikov, K.M. Gorchakov, A.N. Kirpotin, A.N. Skrinskii, 2011, published in Zhurnal Eksperimental’noi i Teoreticheskoi Fiziki, 2011, Vol. 140, No. 2, pp. 247–255. 213 1. INTRODUCTION Since 1974, the VEPP-2M electron–positron col- lider at Novosibirsk has successfully operated in the energy range from the hadron production threshold to 1.4 GeV in the center-of-mass system (CMS). A lumi- nosity integral of ~74 pb –1 was collected by the SND (spherical neutral detector) and CMD-2 (cryogenic magnetic detector). This allowed detailed study of most hadron e + e – annihilation channels. At the same time, the total number of events obtained in other experiments at energies of up to 2 GeV, where excited states of ordinary and strange quarks occur, did not exceed 10% of the data obtained using the VEPP-2M. Therefore, in spring 2000, at the Institute of Nuclear Physics, Siberian Branch, Russian Academy of Sci- ence, it was decided to modernize the VEPP-2M accelerator facility to increase the luminosity to 10 32 cm –2 s –1 and to increase the maximum energy to 2 × 1 GeV, which makes it possible to significantly increase the potential of experiments at the facility. The new project was called VEPP-2000 [1]. The physics program of the VEPP-2000 collider is as follows. (i) Precision measurement of the value of R = σ (e + e – hadron)/σ(e + e – μ + μ – ). (ii) Study of hadron channels of e + e – 2h, 3h, 4h, …, h = π, K, η annihilation. (iii) Study of excited states of vector mesons ρ', ρ'', ω', ϕ', … . (iv) Testing of the hypothesis of conservation of the vector current (CVC test), i.e., comparison of the cross section of e + e – hadron (T = 1) annihilation with the τ decay spectrum. (v) Study of electromagnetic form factors of nucleon–antinucleon pair production and the search for resonances. (vi) Hadron production during “radiative return.” (vii) Two-photon physics. (viii) Testing of quantum electrodynamics theory for higher orders 2 4, 5. To achieve the design parameters (energy and luminosity), the concept of round beams was pro- nn NUCLEI, PARTICLES, FIELDS, GRAVITATION, AND ASTROPHYSICS The VEPP-2000 Electron–Positron Collider: First Experiments D. E. Berkaev a,b, *, D. B. Shwartz a,b , P. Yu. Shatunov a , Yu. A. Rogovskii a,b , A. L. Romanov a , I. A. Koop a,b , Yu. M. Shatunov a,b , I. M. Zemlyanskii a , A. P. Lysenko a , E. A. Perevedentsev a,b , A. S. Stankevich a , A. I. Senchenko a , B. I. Khazin a , A. V. Anisenkov a , S. E. Gayazov a , A. N. Kozyrev a , A. E. Ryzhenenkov a , D. N. Shemyakin a , L. B. Epshtein a , S. I. Serednyakov a , P. M. Astigeevich a , D. P. Kovrizhin a , K. A. Martin a , A. E. Obrazovskii a , I. K. Surin a , L. V. Kardapoltsev a , O. V. Belikov a,b , K. M. Gorchakov a , A. N. Kirpotin a , and A. N. Skrinskii a a Budker Institute of Nuclear Physics, Siberian Branch, Russian Academy of Science, pr. Akademika Lavrent’eva 11, Novosibirsk, 630090 Russia b Novosibirsk State University, ul. Pirogova 2, Novosibirsk, 630090 Russia * e-mail: D.E.Berkaev@inp.nsk.su Received November 12, 2010 Abstract—In 2007, at the Institute of Nuclear Physics (Novosibirsk), the construction of the VEPP-2000 electron–positron collider was completed. The first electron beam was injected into the accelerator structure with turned-off solenoids of the final focus. This mode was used to tune all subsystems of the facility and to train the vacuum chamber using synchrotron radiation at electron currents of up to 150 mA. The VEPP-2000 structure with small beta functions and partially turned-on solenoids was used for the first testing of the “round beams” scheme at an energy of 508 MeV. Beam–beam effects were studied in strong–weak and strong–strong modes. Measurements of the beam sizes in both cases showed a dependence corresponding to model predictions for round colliding beams. Using a modernized SND (spherical neutral detector), the first energy calibration of the VEPP-2000 collider was performed by measuring the excitation curve of the phi- meson resonance; the phi-meson mass is known with high accuracy from previous experiments at VEEP-2M. In October 2009, a KMD-3 (cryogenic magnetic detector) was installed at the VEPP-2000 facility, and the physics program with both the SND and LMD-3 particle detectors was started in the energy range of 1– 1.9 GeV. This first experimental season was completed in summer 2010 with precision energy calibration by resonant depolarization. DOI: 10.1134/S1063776111060136