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The Budker Institute of Nuclear Physics, Siberian Branch, Russian Academy of Sciences (BINP SB RAS), plans to create the Super Charm-Tau Factory (SCTF) accelerator complex, it will operate in a wide energy range of 2E = 2–5 GeV in c.m. and have design luminosity of L = 1 × 1035 cm–2 s–1. As part of the physical program, it is proposed to carry out the experiment by measuring the Weinberg running weak mixing angle for the J/ψ meson energy. Due to the smallness of the predicted effect, it is necessary to exclude the influence of systematic errors from unpredictable changes in the magnet lattice and the beam background. To do this, we have to organize frequent changes in sign of the longitudinal polarization of the electron beam at the interaction point. In this paper we have investigated the possibility of the spin-flip using the spin RF-rotator in a colliding electron ring with three Siberian snakes. Based on the simulation results, conclusions about the possibility of using this approach are made. [ABSTRACT FROM AUTHOR]

In future electron-positron colliders, such as FC-ee and CEPC, it is planned to accurately measure the beam energy by resonance depolarization. In this paper, we propose an alternative approach based on the rapid resonant rotation of the spins into the horizontal plane of the ring and their subsequent free rotation around the equilibrium vertical direction. The frequency of free coherent spin precession is proposed to be measured by the beats of the number of scattering events of electrons interacting with circularly polarized laser light. Fourier analysis of the number of electrons dropped out of the ring aperture to determine the frequency of free precession. In this paper, spin dynamics is simulated at all stages of the process, taking into account synchrotron oscillations and energy diffusion, and statistical estimates of the accuracy of determining the frequency of spin precession for beam parameters in FCC-ee are made. [ABSTRACT FROM AUTHOR]

VEPP-2000 is the only electron–positron collider with round beams. This factor enables one to increase the beam–beam effect limit. During the 2018–2019 season, the experimental program was focused on the energy range of 550–990 MeV per beam. Data accumulation was performed using CMD-3 and SND detectors. The measured luminosity integral proved to have a record value of 68 pb–1 per detector. After connecting to the BINP injection complex in 2016, the luminosity of VEPP-2000 is limited by the beam–beam effects in the entire energy range. [ABSTRACT FROM AUTHOR]

Possible approaches to experimentally detecting P-parity violation in polarized proton or deuteron interactions with an unpolarized target are discussed. Within the first approach, a polarized proton or deuteron beam is scattered on a thick internal target deployed in one of rings of the NICA collider, and the spin state of the circulating beam is transformed to the mode of precession in the horizontal plane using an RF spin flipper. In this case, parity-violating effects can be probed by measuring the correlation between the interaction cross section and the particle spin direction. In an alternative experimental approach, beam-particle spins are rotated into the horizontal plane using a spin flipper, and then the beam is extracted to a beamline at a definite stage of spin precession. In this experimental scheme, which can be viewed as more traditional, one then collides the extracted beam with a dense external target and compares the measured cross sections for particles with opposite helicities passing through the target. [ABSTRACT FROM AUTHOR]

The VEPP-2000 electron-positron collider has been operating at the Budker Institute of Nuclear Physics (BINP) since 2010. Applying the concept of round colliding beams allowed the record value of the beam-beam parameter ξ ∼ 0.12 to be reached. The upgrading of the VEPP-2000 complex, including the connection to the new BINP Injection Complex and modification of the electron-position booster and the BEP-VEPP-2000 transfer channels to work at 1 GeV, resulted in a significant increase in luminosity. Work on statistical data collection using detectors is in progress. [ABSTRACT FROM AUTHOR]

One of the main tasks of the NICA project is to produce colliding beams of polarized protons. It is planned to accelerate polarized protons from the source to the maximum energy in the existing proton synchrotron. We consider all depolarizing spin resonances in the Nuclotron and propose methods to overcome them. [ABSTRACT FROM AUTHOR]

The e e → ηππ cross section in the η → 2γ channel has been measured in the $$ \sqrt s $$ = 1.04- to 1.38-GeV energy range. The data with a total integrated luminosity of 9.05 pb were collected on a spherical neutral detector at the VEPP-2M collider. The results are consistent with the BaBar and CMD2 data and have a higher statistical accuracy. [ABSTRACT FROM AUTHOR]

We have searched for the process e+e- → K+K-π0 at energies up to 1.38 GeVin an experiment with the spherical neutral detector at the VEPP-2M e+e- collider. The upper limits of the cross sections for the processes σ(e+e →; φπ: → K+K-π0) < 0.023 nb and σ(e+e- → KK*(892) → K+K-π0) < 0.059 nb have been established at a 95% confidence level. [ABSTRACT FROM AUTHOR]

The cross section for the process e+ e− → π+π−π0π0 has been measured in an experiment with a spherical neutral detector, with the cross section at energies √ s < 920 MeV having been measured for the first time. The model of vector dominance describes well the data obtained if the ρ, ρ′, and ρ″ resonances are taken into account. The probability of the decay ρ → π+π−π0π0 is B(ρ → π+π−π0π0) = (1.60 ± 0.74 ± 0.18) × 10−5. The upper limit for the decay ω → π+π−π0π0 has been improved by two orders of magnitude compared to previous measurements and is B(ω → π+π−π0π0) < 2 × 10−4 at a 90% confidence level. [ABSTRACT FROM AUTHOR]

The e + e − → ω, ρ → π0 e + e − processes have been investigated in the experiments with Spherical Neutral Detector at the VEPP-2M e + e − collider. The measurements provide the probability ℬ(ω → π0 e + e −) = (0.761 ± 0.053 ± 0.064) × 10−3 of the ω → π0 e + e g- conversion decay and the upper limit ℬ(ρ → π0 e + e −) < 1.2 × 10−5 (at 90% CL) for the ρ → π0 e + e − decay. The transition form factor was measured at three values of the 4-momentum transfer squared. [ABSTRACT FROM AUTHOR]

The corrected cross section of the e + e − → π+π− process measured in the spherical neutral detector experiment at the VEPP-2M e + e − collider is presented. The update is necessary due to a flaw in the e + e − → π+π− and e + e − → μ+μ− Monte Carlo event generators used previously in data analysis. [ABSTRACT FROM AUTHOR]

The cross section of the process e+e- ↵ π+π- was measured in the spherical neutral detector experiment at the VEPP-2M collider in the energy region 400 < √s < 1000 MeV. This measurement was based on about 12.4 ⊗ 106 selected collinear events, which include 7.4 ⊗ 106 e+e- ↵ e+e-, 4.5 ⊗ 106 e+e- ↵ π+π-, and 0.5 ⊗ 106 e+e- ↵ μ+μ- selected events. The systematic uncertainty of cross section determination is 1.3%. The r-meson parameters were determined as mρ = 774.9 ± 0.4 ± 0.5 MeV, Γρ = 146.5 ± 0.8 ± 1.5 MeV, and σ(ρ ↵ π+π-) = 1220 ± 7 ± 16 nb and the parameters of the G-parity suppressed decay ω π+π- as σ(ω ↵ π+π-) = 29.9 ± 1.4 ± 1.0 nb and Φρω = 113.5 ± 1.3 ± 1.7°. [ABSTRACT FROM AUTHOR]

Results from the Spherical Nonmagnetic Detector (SND) on Δ(1232) isobar electroproduction in the collisions of beam electrons (positrons) and residual gas nuclei in the VEPP-2M e[sup +]e[sup -] collider are presented. On the basis of the data obtained the expected counting rate of this process in future high-luminosity e[sup +]e[sup -] colliders (φ, c-τ, and b factories) is estimated. [ABSTRACT FROM AUTHOR]