Yuri Shatunov

Electron cooling for RHIC

We introduce plans for electron-cooling of the Relativistic Heavy Ion Collider (RHIC). This project has a number of new features as electron coolers go: It will cool 100 GeV/nucleon ions with 50 MeV electrons; it will be the first attempt to cool a collider at storage-energy; and it will be the first cooler to use a bunched beam and a linear accelerator as the electron source. The linac will be superconducting with energy recovery. The electron source will be based on a photocathode gun. The project is carried out by the Collider-Accelerator Department at BNL in collaboration with the Budker Institute of Nuclear Physics.

Study of e+e-→ωπ0→π0π0γ in the energy range 1.05-2.00 GeV with the SND detector

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.

Electron Cooling of RHIC

We report progress on the R&D program for electron-cooling of the Relativistic Heavy Ion Collider (RHIC). This electron cooler is designed to cool 100 GeV/nucleon at storage energy using 54 MeV electrons. The electron source will be a superconducting RF photocathode gun. The accelerator will be a superconducting energy recovery linac. The frequency of the accelerator is set at 703.75 MHz. The maximum electron bunch frequency is 9.38 MHz, with bunch charge of 20 nC. The R&D program has the following components: The photoinjector and its photocathode, the superconducting linac cavity, start-to-end beam dynamics with magnetized electrons, electron cooling calculations including benchmarking experiments and development of a large superconducting solenoid. The photoinjector and linac cavity are being incorporated into an energy recovery linac aimed at demonstrating ampere class current at about 20 MeV.

Comissioning of Upgraded VEPP-2000 Injection Chain

The upgrade of VEPP-2000 ee collider injection chain includes the connection to BINP Injection Complex (IC) via newly constructed transfer line K-500 as well as upgrade of the booster synchrotron BEP to the energy of 1 GeV. Modernization has started in the middle of 2013 and now the electron and positron beams with highly increased production rate together with top-up injection from BEP are ready to feed VEPP-2000 ring and provide design luminosity at the whole energy range limited only by beam-beam effects. The design and operation experience of IC damping ring, 250 m transfer channel and booster BEP dealing with 2.6 T magnets at top energy will be presented.

Recent Beam-Beam Effects at VEPP-2000 and VEPP-4M

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. VEPP-4M Being a rather old machine with a moderate luminosity, VEPP-4M has several unique features, firstly a very low beam-energy spread, and a system for precise energy measurement, providing an interesting particle physics program for the KEDR detector. Over recent years VEPP4M was taking data at a low energy range with two bunches in each beam. The luminosity at this range is limited by beam–beam effects with the threshold beam– beam parameter ξy ≤ 0.04 [1]. In this case the luminosity

Measurement of the e{sup +}e{sup {minus}}{r_arrow}{pi}{sup +}{pi}{sup {minus}} cross-section with the CMD-2 detector

The general purpose detector CMD-2 at the VEPP-2M electron-positron collider at Novosibirsk has collected about 11 pb−1 of integrated luminosity in the center-of-mass energy range from 0.36 up to 1.38 GeV. Data in the ρ-meson energy range from 0.61 to 0.96 GeV have been analysed and preliminary results on the e+e−→π+π− cross-section in this energy range are presented.