M. N. Achasov, 2 V. M. Aulchenko, 2 A. Yu. Barnyakov, 2 K. I. Beloborodov, 2 A. V. Berdyugin, 2 D. E. Berkaev, 2 A. G. Bogdanchikov, A. A. Botov, T. V. Dimova, 2 V. P. Druzhinin, 2 V. B. Golubev, 2 L. V. Kardapoltsev, 2 A. S. Kasaev, A. G. Kharlamov, 2 A. N. Kirpotin, I. A. Koop, 2, 3 L. A. Korneev, ∗ A. A. Korol, 2 D. P. Kovrizhin, S. V. Koshuba, A. S. Kupich, 2 N. A. Melnikova, 2 K. A. Martin, A. E. Obrazovsky, A. V. Otboev, E. V. Pakhtusova, K. V. Pugachev, 2 Yu. A. Rogovsky, 2 A. I. Senchenko, 2 S. I. Serednyakov, 2 Z. K. Silagadze, 2 Yu. M. Shatunov, 2 D. A. Shtol, D. B. Shwartz, 2 I. K. Surin, Yu. V. Usov, and A. V. Vasiljev 2 Budker Institute of Nuclear Physics, SB RAS, Novosibirsk, 630090, Russia Novosibirsk State University, Novosibirsk, 630090, Russia Novosibirsk State Technical University, Novosibirsk, 630092, Russia

Injection Complex VEPP-5 was turned into operation in the end of 2015 in the Budker Institute of Nuclear Physics (Novosibirsk, Russia). The main task of the facility is production, acceleration and transportation of high intensity electron and positron beams for two BINP's colliders. Now, VEPP-5 successfully delivers electron and positron beams to the collider VEPP-2000 and ready to start operation with the acceleration complex VEPP-4M. Beam diagnostics issues are very important for VEPP-5 facility tuning during the operation. Longitudinal beam diagnostic based on synchrotron radiation in the VEPP-5 Damping Ring is presented in the article. Equipment operation principle, main measurement results and future prospects are presented in this paper.

We analyze a 37 pb(-1) data sample collected with the SND detector at the VEPP-2000 e(+)e(-) collider in the center-of-mass energy range 1.05-2.00 GeV and present an updated measurement of the e(+)e(-) -> omega pi(0) -> pi(0) pi(0) gamma cross section. In particular, we correct the mistake in radiative correction calculation made in our previous measurement based on a part of the data. The measured cross section is fitted with the vector meson dominance model with three rho-like states and used to test the conserved vector current hypothesis in the tau(-) -> omega pi(-) nu(tau) decay.

M. N. Achasov, 2 A. Yu. Barnyakov, K. I. Beloborodov, 2 A. V. Berdyugin, 2 D. E. Berkaev, 2 A. G. Bogdanchikov, A. A. Botov, T. V. Dimova, 2 V. P. Druzhinin, 2 V. B. Golubev, 2 L. V. Kardapoltsev, 2, ∗ A. S. Kasaev, A. G. Kharlamov, A. N. Kirpotin, D. P. Kovrizhin, 2 I. A. Koop, 2, 3 A. A. Korol, 2 S. V. Koshuba, K. A. Martin, A. E. Obrazovsky, E. V. Pakhtusova, Yu. A. Rogovsky, A. I. Senchenko, S. I. Serednyakov, Z. K. Silagadze, 2 Yu. M. Shatunov, 2 D. A. Shtol, 2 D. B. Shwartz, 2 A. N. Skrinsky, I. K. Surin, 2 and A. V. Vasiljev 2 Budker Institute of Nuclear Physics, SB RAS, Novosibirsk, 630090, Russia Novosibirsk State University, Novosibirsk, 630090, Russia Novosibirsk State Technical University, Novosibirsk, 630092,Russia We analyze a 37 pb data sample collected with the SND detector at the VEPP-2000 ee collider in the center-of-mass energy range 1.05–2.00 GeV and present an updated measurement of the ee → ωπ → ππγ cross section. In particular, we correct the mistake in radiative correction calculation made in our previous measurement based on a part of the data. The measured cross section is fitted with the vector meson dominance model with three ρ-like states and used to test the conserved vector current hypothesis in the τ− → ωπ−ντ decay.

Budker INP hosts two e+e- colliders, VEPP-4M operating in the beam energy range of 1-5.5 GeV and the low-energy machine VEPP-2000, collecting data at 160-1000 MeV per beam. The latter uses a novel concept of round colliding beams. The paper presents an overview of observed beam-beam effects and obtained luminosities.

The idea of round-beam collision was proposed more than 20 years ago for the Novosibirsk Phi-factory design. [1] It requires equal emittances, equal small fractional tunes, equal beta functions at the IP, no betatron coupling in the collider arcs. Such an approach results in conservation of the longitudinal component of angular momentum. As a consequence, it yields an enhancement of dynamical stability, even with nonlinear effects from the beam-beam force taken into account. The Round Beam Concept (RBC) was realized at the electronpositron collider VEPP-2000 and successfully tested at the energy of 510 MeV. [2] Despite the low energy, a high single-bunch luminosity of 10 31 cm -2 s -1 was achieved together with a maximum tune shift as high as 0.1. At present the work is in progress to increase the energy of the collider to explore the range between 500 MeV and 1 GeV in collision.

VEPP-2000 electron-positron collider has been completed in the Budker INP in 2007. First beam was captured in a special lattice with switched off final focus solenoids. This regime is used for all machine subsystems test and calibration as well as vacuum chamber treatment by synchrotron radiation with electron beam current up to 150 mA. Another special low-beta lattice with solenoids switched on partially was used for the first test of the round beam option at the energy of 508 MeV. Studies of the beam-beam interaction were done in “weak-strong” and “strong-strong” regimes. Measurements of the beam sizes in both cases have indicated beam behaviour similar to expectations for the round colliding beams. Also the first collider energy calibration at the phi-meson resonance was performed with SND detector. Since the end of 2009 VEPP-2000 started first experimental work with both particle detectors SND and CMD-3 at the energies of 500-950 MeV range with the lattice mode close to project. The precise energy calibration via resonant depolarization method is in progress.