The paper presents solution of quantum problem of neutron propagation in the magnetic field with multipole field expansion. Rigorous solution of the Pauli equation for neutron reveals existence of two solutions, finite and infinite, for any multipole configuration. As an example, we present detailed study of neutron motion in quadrupole and sextupole magnets. Our predictions agree with the results of Stern-Gerlach experiment for neutrons. To verify existence of finite and infinite motion, we discuss an experiment which could be performed in the Budker Institute of Nuclear Physics using existing equipment. We conclude with considerations of neutron storage ring with straight section and discrete magnets focusing the beam.

New measurements of the T20 component of tensor analyzing power in the reaction γd→ppπ− for photon energies 400−700 MeV are presented. The experiment was carried out on an internal tensor-polarized gas deuterium target of the VEPP-3 electron storage ring in 2023 with the use of tagged quasi-real photons and two-proton coincidence. For determination of T20, the asymmetry caused by a change of the sign of the tensor polarization of the deuteron target was measured. The new data are compared with the results of theoretical calculations based on the quasi-free approximation including πN and NN rescattering effects.

All modern electron-positron collider designs use Crab Waist collision scheme as a basic principle for substantial luminosity increase. However, this approach has strong demands on beam dynamics and technical collider design, which are very difficult to satisfy. This paper discusses a program to study fundamental features of Crab Waist collision scheme at Budker Institute of Nuclear Physics.

To obtain a harder energy spectrum and increase the photon flux and brightness of synchrotron radiation of the Synchrotron Radiation Facility—Siberian Circular Photon Source “SKlF” synchrotron light source, it is planned to use multipole superconducting insertion devices—radiation generators (wigglers and undulators). Having a short period and large amplitude of the magnetic field, such devices have a serious impact on the optics and dynamics of the electron beam. In the proposed work, we consider various aspects of this influence (changes in radiation parameters, distortion of optical functions, and a reduction in dynamic aperture) and discuss possible options for correcting the undesirable consequences of installing wigglers and undulators in the SKIF storage ring.

The experiment on photodisintegration of tensor polarized deuteron is in progress. It is carried out at VEPP-3 storage ring using the internal polarized gas target technique. The component T20 of the tensor analyzing power is obtained by measuring the target polarization asymmetry in the photon energy range up to 1600MeV. The energy of photons is defined by the system that tags nearly real photons developed at the Budker Institute of Nuclear Physics (BINP).

The Resource Sharing Centre "The Siberian Circular Photon Source" "SKIF")-is a fourth-generation synchrotron radiation (SR) source currently under construction in Novosibirsk. Ensuring the mechanical stability of the magnetic elements of a modern SR source is a complex and important task, since even small displacements of magnets relative to the design position, caused, among other things, by seismic vibrations of the construction site surface, can significantly degrade the installation parameters. The article presents the results of a study of the seismic situation in the area of the construction site of the "SKIF," the main sources of the seismic background are identified and, based on the data obtained, the parameters of the feedback system are estimated, which allows dynamically adjusting the position of the electron beam at radiation points, stopping the negative impact of seismic effects on the efficiency of the SR source work.

Electron-positron collider Super Charm Tau factory is planned to be built in the National center for physics and mathematics, Sarov. It is a double ring collider with crab waist collision scheme operating in wide beam energy range from 1.5 GeV to 3.5 GeV with peak luminosity of 10 35 cm -2 s -1 . The polarized electron source and three Siberian Snakes provide 80% longitudinally polarized electron beam at 2 GeV. Superconducting wigglers decrease damping times, effects of intra-beam scattering and increase Touschek beam lifetime, particularly at low energy. The paper presents the status of collider design and optimization of luminosity and beam lifetime.

— The review presents the experiments performed with the KEDR detector at the e^ + e^ - collider VEPP-4M in the energy range of √(s) = 1.84–3.88 GeV. The cross section of e^ + e^ - annihilation to hadrons was measured at 22 points of this range and the search for narrow resonances was conducted below 3.1 GeV. The masses of J / . -0emψ and ψ (2S) mesons were measured with a record accuracy better than 3 ×10^ - 6 ; their partial and total widths were determined. Measurements of the tau lepton mass and masses of charged and neutral D mesons were performed with high precision. The measurements of the ψ (3770) parameters are discussed, and attention is drawn to some inconsistency of the procedure employed by the Particle Data Group for determining its parameters.

Using the MADX options, the stages of orbit correction and then optics correction were simulated, taking into account the specified tolerances for the positioning of magnetic elements and girders in the Siberian Circular Photon Source (SKIF, the Russian acronym). Numerical modeling of hte effect of residual perturbations of the guide field on the vertical emittance and vertical size of the beam has been carried out. A generalized method of skew-quadrupole coupling correction in SKIF has been developed and verified by simulation, which allows simulteneously minimizing the vertical dispersion and compensating for the linear difference coupling resonance.

New results for the T20-component of the tensor-analyzing power of the incoherent negative pion photoproduction are presented. The experiment was performed for the electron beam energy of 800 MeV at the VEPP-3 storage ring in 2021. To extract the T20-component, we used asymmetry with respect to the change in the sign of the tensor polarization of the deuteron target. Identification of the reaction events was carried out by the detection of two protons in coincidence. Experimental data were compared with the results of statistical simulation, considering the interaction between the NN and πN subsystems in the final state of the reaction.

We present the study of the decay J/ψ → ρπ . The results are based on of 5.2 million J/ψ events collected by the KEDR detector at the VEPP-4M collider. The branching fractions are measured to be ℬ ( J/ψ → ρπ ) = (2 . 072 ± 0 . 017 ± 0 . 062) ∙ 10 − 2 and ℬ ( J/ψ → π + π − π 0 ) = (1 . 878 ± 0 . 013 ± 0 . 051) ∙ 10 − 2 , where the first uncertainties are statistical and the second systematic. Our results are more precise than the previous relative measurements.

The super τ-charm facility (STCF) is an electron–positron collider proposed by the Chinese particle physics community. It is designed to operate in a center-of-mass energy range from 2 to 7 GeV with a peak luminosity of 0.5 × 1035 cm−2·s−1 or higher. The STCF will produce a data sample about a factor of 100 larger than that of the present τ-charm factory — the BEPCII, providing a unique platform for exploring the asymmetry of matter-antimatter (charge-parity violation), in-depth studies of the internal structure of hadrons and the nature of non-perturbative strong interactions, as well as searching for exotic hadrons and physics beyond the Standard Model. The STCF project in China is under development with an extensive R D program. This document presents the physics opportunities at the STCF, describes conceptual designs of the STCF detector system, and discusses future plans for detector R D and physics case studies.

The Center for Collective Use “Siberian Center for Synchrotron and Terahertz Radiation” provides users from various organizations with the opportunity to use modern analytical techniques using synchrotron radiation beams for a wide range of research work. At present, the general direction of the development of new techniques is focused on the development of new original approaches to the use of synchrotron radiation.

Particle accelerators are unique scientific tools that offer unrivalled energy per constituent of their charged particle beams compared to sources normally available in laboratories.Focused high-density beams of electrons, positrons, protons, antiprotons, ions, and other elementary particles are used.Since the early twentieth century, accelerators have been widely applied to physics research, and great progress in science and technology has been driven by the development of more and more powerful accelerators needed for fundamental physics research [1].Circular accelerators, and specifically colliders, occupy a special place [2, 3] among particle accelerator facilities.These innovative scientific tools allowed fundamental advances in scientific discoveries in high-energy physics.Collider technology and beam physics have advanced greatly, and modern facilities are now operating with energy and luminosity of several orders of magnitude higher than those of pioneer colliders in the early 1960s.Analysis of all Nobel Prize-winning physics research since 1939 [4] reveals that accelerators have played an integral role in influencing more than a quarter of physics prize recipients by either inspiring them or facilitating their research.Moreover, accelerators have contributed on average to one Nobel Prize in physics per three years [5], and four Nobel Prizes directly recognised breakthroughs in accelerator science and technology.Physics, however, is not the only domain of science to profit from the use of particle accelerators.Notably, synchrotron radiation sources based on accelerators have recently been instrumental in a number of Nobel Prize-winning research achievements in chemistry and biology.Nuclear physics is another field that has benefited from the progress made by particle accelerators [6].According to recent data [7], currently about 140 accelerators of all types are devoted to fundamental research, while in 2012 the EU's TIARA project identified 125 European public sector accelerator infrastructures in 12 countries (Austria, Denmark, Finland, France, Germany, Italy, Poland, Slovenia, Spain, Sweden, Switzerland, and the UK).Accelerator applications are particularly notable in medicine [8,9] and industry in general [10][11][12].Beyond the key role of particle accelerators as powerful instruments that is generally well known and unanimously accepted, they themselves represent an incredible source of exciting physical problems stemming from the dynamics of the charged particles that travel inside these devices.By restricting to the broad class of circular accelerators, it is nowadays fully recognised that the challenges posed by the analysis of the stability of particle beams are equivalent to those considered in Celestial Mechanics.This issue has become more relevant with the advent of superconducting accelerators, where unavoidable multipolar field errors in the main magnets make the beam dynamics intrinsically nonlinear.This has opened up the possibility of cross-fertilisation between accelerator physics and the vast and well-established field of nonlinear dynamical systems, and nonlinear physics became a fundamental background of an accelerator physicist.A circular accelerator with high-quality beam instrumentation, controllable nonlinearities, changeable tunes, etc. is an excellent tool not only for high-energy physics but also for dynamical studies (chaotic and regular motion, dynamic systems stability, etc.).These general considerations led us to undertake the enterprise represented by this Focus Point, whose goal is to showcase a selection of topics related to advances, challenges, and applications of high-energy accelerator physics.The excellent contributions included in this Focus Point testify to the vitality and diversity of scientific problems that emerge from the analysis of beam dynamics.They all indicate clearly that particle accelerators are by far not mere tools for scientific experiments.In this respect, it is our hope that accelerator physics will find its appropriate way in academia in the next future.Indeed, it is a common observation that accelerator physics is not taught in the physics departments and it is not part of the typical curriculum for master's degree in physics.Some exceptions to this rule are when a laboratory housing an accelerator is located in the vicinity of a university.It is hoped that this situation may change in the future, with a more generalised teaching of accelerator physics, particularly the more advanced aspects, such as nonlinear dynamics, collective effects, etc.It would be a great pleasure if this Focus Point could become an incentive to make some progress in this direction!

An Erratum to this paper has been published: https://doi.org/10.3103/S106287382301001X

The results of an experimental study of seismic vibrations at the site for the construction of the Siberian Ring Photon Source (SKIF), which is a synchrotron radiation source of the fourth plus generation at 3 GeV and a perimeter of 480 m, have been considered. Seismic vibrations are a hindrance that reduces the accuracy of the experimental setup when studying materials with precision accuracy and resolution. The experiment was performed with broadband seismological equipment used at seismological stations. Seismic vibrations from different types of sources have been investigated: natural and man-made earthquakes, industrial explosions, noises of automobile and railway transport, vibrations from industrial equipment at enterprises located away from the facility under construction. Natural earthquakes create the strongest broadband impact on the site. Man-made earthquakes in the area of the Gorlovka coal basin can create short-term strong seismic impacts. Industrial explosions in terms of the seismic impact on the site are significantly inferior to the effects of earthquakes and are characterized by a more limited spectral composition of vibrations. The noises of motor transport cover frequencies from 4 to 30 Hz and quickly fade away along the site with distance from the road. Railway noises have the characteristic appearance of a set of multiple harmonics covering a wide frequency range with a duration of up to 10 min. Monochromatic signals from the operation of industrial equipment on and off the site are recorded at the site. At the same time, both continuous signals and those that occur episodically are recorded. A special class consists of monochromatic oscillations with a slowly varying frequency. The information on the level, spectrum, and duration of seismic vibrations necessary for calculating the seismic protection of the SKIF Central Research Center during its creation and development of a seismological monitoring system that compensates for the seismic effect on the accuracy of experiments was obtained.

supervisor of the scientific area Synchrotron radiation (SR) at the Budker Institute of Nuclear Physics of the Siberian Branch of the Russian Academy of Sciences (SB RAS) and director of the Siberian Center of Synchrotron and Terahertz Radiation, academician Gennadii Nikolaevich Kulipanov. Gennadii Nikolaevich was born on January 25, 1942 in the town of Shchuchinsk in the Kokchetav region of Kazakh SSR. In 1963, he graduated from the Novosibirsk Electrotechnical Institute (now Novosibirsk State Technical University). Since 1963, he has been working at the Budker Institute of Nuclear Physics (BINP) SB RAS. He was elected a correspondingmember of RAS in 1997 and a full member in 2003. G NKulipanov's main studies have been dealing with the physics of nonlinear oscillations of particles in colliders, the generation and application of synchrotron radiation, and the creation of free-electron lasers. While working at the electron±electron collider VEP-1, Gennadii Nikolaevich studied experimentally, for the first time in the world, nonlinear resonances and stochastic instability of nonlinear oscillations at a cyclic accelerator to confirm the results of some theoretical predictions. Later on, guiding the start-up of the VEPP-3 electron±positron collider, Kulipanov continued investigating the nonlinear beam dynamics and simultaneously taught students, postgraduates, and trainees, who then became leading research fellows at BINP. The knowledge of particle dynamics gained in the colliders was then used by G N Kulipanov and his school to design high-radiance (low electron beam emittance) synchrotron radiation sources. By the mid-1970s, it had become clear that electron colliders, in particular, VEPP-3, can be used not only for high-energy physics but also to generate high-power synchrotron radiation with record-high spectral radiance. Gennadii Nikolaevich took an active part in working out the method of evacuation of synchrotron radiation from an accumulator vacuum chamber for a further employment of this radiation in applied experiments. Gennadii Nikolaevich advocated actively the unique properties of synchrotron radiation among members of the physical, chemical, and biological scientific communities. The widely known review, ``Utilization of synchrotron radiation: current status and prospects,'' published in the journal Uspekhi Fizicheskikh Nauk [UFN 122 369 (1977); Phys. Usp. 20 559±586 (1977)] and written together with A N Skrinskii, became a handbook for many scientists using synchrotron radiation in their studies. Gennadii Nikolaevich was an organizer and chairman of the All-Union Council in Novosibirsk on synchrotron radiation physics. Since the mid-1980s, this council has become a regularly held international conference on synchrotron radiation physics, which has in fact become the leader of the new area in Russian and world science. At the Russian research center Kurchatov Institute, G N Kulipanov and his colleagues designed and started up a specialized X-ray radiation source, Sibir'-2 (now referred to as KISI-Kurchatov), with an electron energy of 2.5 GeV, which is now the only one in Russia. Under his guidance, a superconducting multipole wiggler, a constant-magnet ondulator with a variable operating gap and a hybrid (i.e., with iron poles) constant-magnet ondulator were tested and exploited in experiments at the VEPP-3 storage ring for the first time in the world. These original constructions are now being used in dozens of facilities. G N Kulipanov and his colleagues proposed and implemented schemes for staging some experiments using specific features of synchrotron radiation, and elaborated and designed experimental equipment adequate for a radiation source, whichmade it possible to establish the SiberianCenter of Synchrotron Radiation on the basis of electron±positron Uspekhi Fizicheskikh Nauk 192 (1) 115 ± 116 (2022) Translated by M V Tsaplina PERSONALIA PACS number: 01.60.+q

Due to the Sokolov–Ternov natural radiative mechanism, the electron–positron storage rings feature a unique possibility of creating spin polarization of circulating beams. The resulting transverse polarization of particles is mainly used to precisely calibrate the beam energy by measuring the spin precession frequency using the resonant depolarization technique (RD). RD is considered the most accurate method for instantaneous determination of particle energy. To date, RD has been applied in several laboratories around the world to measure the mass of various particles. The best result was obtained in experiments at BINP (Budker Institute of Nuclear Physics of the Siberian Branch of the Russian Academy of Sciences) on the VEPP-4M collider with the KEDR detector, in which the masses of narrow resonances of $$J/\psi $$ and $$\psi (2S)$$ were measured with a world-record accuracy of $$10^{-6}$$ . We describe the principles and technical details of application of the resonant depolarization at the VEPP-4M collider. Experimental results are presented for various conditions of measuring the spin precession frequency by this method. The experience gained allows us to discuss possible features of RD application at future Higgs and Electroweak $$e^+e^-$$ Factories from the projects FCC-ee and CEPC.

Using the 1.32 pb^-1 statistics collected at the J/ψ peak with the KEDR detector at the VEPP-4M e^+e^- collider, we measured the branching fractions of J/ψ meson decays to the final states 2( π ^+π ^-)π ^0 , K^+K^-π ^+π ^-π ^0 , 2( π ^+π ^-) and K^+K^-π ^+π ^- . The results obtained for the decays J/ψ→ 2( π ^+π ^-)π ^0 , J/ψ→ K^+K^-π ^+π ^-π ^0 contradict the measurements performed by other groups in the last century, but agree well with recent results of BABAR and BESIII collaborations.

Abstract Using the 1.32 $$\hbox {pb}^{-1}$$ pb - 1 statistics collected at the $$J/\psi $$ J / ψ peak with the KEDR detector at the VEPP-4M $$e^{+}e^{-\, }$$ e + e - collider, we measured the branching fractions of $$J/\psi $$ J / ψ meson decays to the final states 2( $$\pi ^{+}\pi ^{-})\pi ^{0}$$ π + π - ) π 0 , $$K^{+}K^{-}\pi ^{+}\pi ^{-}\pi ^{0}$$ K + K - π + π - π 0 , 2( $$\pi ^{+}\pi ^{-})$$ π + π - ) and $$K^{+}K^{-}\pi ^{+}\pi ^{-}$$ K + K - π + π - . The results obtained for the decays $$J/\psi \rightarrow $$ J / ψ → 2( $$\pi ^{+}\pi ^{-})\pi ^{0}$$ π + π - ) π 0 , $$J/\psi \rightarrow K^{+}K^{-}\pi ^{+}\pi ^{-}\pi ^{0}$$ J / ψ → K + K - π + π - π 0 contradict the measurements performed by other groups in the last century, but agree well with recent results of BABAR and BESIII collaborations.