The results of searches for the process e^+e^-→η^'γ in an experiment with the SND detector at the VEPP-2000 electron–positron collider are presented. The data used in these searches and based on an integrated luminosity of about 87 pb ^-1 were accumulated at c.m. energies √(s) between 1.15 and 2 GeV. The upper limits of σ_η^'γ<28 pb for 1.15<√(s)<1.39 GeV and σ_η^'γ<12 pb for 1.39<√(s)<2.00 GeV were set at a 90 % confidence level.

The results of searches for the process $$e^{+}e^{-}\to\eta^{\prime}\gamma$$ in an experiment with the SND detector at the VEPP-2000 electron–positron collider are presented. The data used in these searches and based on an integrated luminosity of about 87 pb$${}^{-1}$$ were accumulated at c.m. energies $$\sqrt{s}$$ between 1.15 and 2 GeV. The upper limits of $$\sigma_{\eta^{\prime}\gamma}<28$$ pb for $$1.15<\sqrt{s}<1.39$$ GeV and $$\sigma_{\eta^{\prime}\gamma}<12$$ pb for $$1.39<\sqrt{s}<2.00$$ GeV were set at a 90$$\%$$ confidence level.

The present status of two operating BINP electron-positron colliders VEPP-2000 and VEPP-4M is given.

The e(+)e(-) -> K+K- cross section is measured in the center-of-mass energy range 1.05-2.00 GeV at the SND detector. The measurement is based on data with an integrated luminosity of 35 pb(-1) collected at the VEPP-2000 e(+)e(-)-collider. The obtained results are consistent with the previous most accurate data obtained in the BABAR experiment and have a comparable accuracy.

In precise experiments with polarized beam it’s very often appear a necessity to change beam polarization on opposite. If such operation does not change other beam parameters, it helps to avoid or minimize some systematic errors. It is especially important in experiments, where spin dependent effect is small enough. This paper describes two set of equipments, that make spin flip for extracted beams. In both cases, these devices are absolutely distinct, because they are appropriate for different particles and at different energy range. The first of them is intended for future muon (g-2) experiment, which is under preparation now at JPARC. Here, the muon spin flip will be done by chain of electrostatic and magnetic bends at the kinetic energy 340 keV. A beam matching is provided by a number of short solenoids. The other flipper (or Siberian snake) will rotate spin of protons or antiprotons, which come from Λ-meson decay with the energy up to 40 GeV. This experiment (no. 24) is planed at IHEP, Protvino. In this case, two superconducting helical magnets with opposite helicities and magnetic field 4.5 T will be used. To correct beam trajectory, additional dipole correctors are required.

The idea of round-beam collision was proposed more than twenty years ago for the Novosibirsk Phi-factory design [V.V. Danilov et al., in Proc of the EPAC 1996, Sitges, vol. 2, p. 1149]. 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 electron-positron collider VEPP-2000 and successfully tested at the energy of 510 MeV [D.E. Berkaev et al., in Proc. of the EPAC 2008, Genoa, p. 956]. Despite the low energy, a high single-bunch luminosity of 1031 cm−2s−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.

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.

Main lattice feature of the new electron-positron collider VEPP-2000 is a solenoidal focusing in two experimental straight sections. Each pair of the 13 T solenoids has an integral magnetic field equivalent to full Siberian snake. Together with high guiding magnetic field (up to 2.4 1), this scheme offers unusual possibilities for the beam radiative polarization. Different sets of solenoid's polarities can provide fast transverse or longitudinal self-polarization quite interesting for future experiments at VEPP-2000. Many interesting studies of polarization phenomena have been done at the synchrotron U-70, during 40 years of its operation. A possibility to accelerate polarized protons at the synchrotron U-70 is considered. To suppress depolarizing effects of spin resonances in the whole energy range of 2.5 - 70 GeV, a scheme with three helical partW Siberian snakes is proposed.

For intermediate energies of electrons and protons it happens that it is more convenient to construct Siberian snakes and spin rotators using solenoidal fields. Strong coupling caused by the solenoids is suppressed by a number of skew and normal quadrupole magnets. More complicate problem of the spin transparency of such devices also can be solved. This paper gives two examples: spin rotator for electron ring in the eRHIC project and Siberian snake for proton (antiproton) storage ring HESR, which cover whole machines working energy region.

A possibility to accelerate polarized proton at the synchrotron U-70 is considered. Estimations of the spin resonances are given in the energy range 2.5...70 GeV. To suppress depolarizing effects of spin resonances, a scheme of three partial Siberian snakes is suggested. Each snake consists from helical magnets with 4.5 T magnetic field. The scheme provides the adiabatic spin flip at imperfection resonances and suppresses all intrinsic resonances by quite realistic beam emittance and magnets misalignments +/- 5 mm.

Acceleration and storage of polarized proton and antiproton beams in medium and high energy circular accelerator are complicated by numerous depolarizing spin resonances. In this paper possible scenarios for accelerating and storing polarized beams in the High Energy Storage Ring (HESR) of the future GSI Facility for Antiprotons and Ions Research (FAIR) [1] are discussed.

The flip-flop effect with the linearized beam-beam force is formulated through self-consistent /spl beta/-functions and equilibrium emittances which are both affected by collision. We give the results of two models of emittance dependence. The effect of finite bunch length is also discussed.

The flip-flop effect with the linearized beam-beam force is formulated through self-consistent β functions and equilibrium emittances which are both affected by collision. We give the results of two models of emittance dependence. The effect of finite bunch length is also discussed.