The present study explores the application transition energy jump procedure in order to maintain the stability of the beam in the NICA collider. The features of the barrier and harmonic accelerating RF stations and their influence on the dynamics of longitudinal particle motion are described. Study of these features is intended to expand the understanding of the process of transition energy crossing.

A number of open questions remain in the manipulation of the spins of colliding beams, which is a key aspect in the operation of polarized beam colliders such as the Nuclotron-based ion collider facility (JINR, Dubna, Russia) and the electron ion collider (BNL, United States). The spin transparency regime, which is the only realistic regime to control the deuteron polarization, has not yet been approved experimentally. With the existing configuration of the JINR accelerator complex, a pilot spin transparency experiment could be performed on a proton beam in the Nuclotron synchrotron. The dynamics of the proton beam polarization during the fast crossing of spin resonance guided by spin navigators based on regular orbit-steerer dipoles has been analyzed in this work. A scheme has been designed to compensate the coherent action of Nuclotron lattice imperfections on spin. In this scheme, the spin field induced by lattice imperfections is determined from the adiabatic deviation of spins in the resonance region, taking into account the synchrotron energy modulation. Integer-resonance strengths can be compensated down to the limits conditioned by orbital beam emittances. The numerical simulation of the proposed spin compensator has confirmed that the spin transparency regime in an imperfect Nuclotron lattice with a strongly distorted closed orbit can be experimentally verified.

The authors describe the process of changing the orientation of the axis of polarization of a beam in developing a way to detect the electric dipole moment of a deuteron at the NICA collider facility (Joint Institute of Nuclear Research, Dubna), as it operates in the storage ring mode. The process is part of developing a procedure for calibrating the so-called effective Lorentz factor of the beam, so it is related to other tasks associated with orienting the axis of polarization in the accelerator. The process is studied to solve two problems: (1) determining the rate of reorientation of the axis required to meet the experimental conditions, and (2) its impact on the polarization coherence of the beam. Preliminary solutions to these problems are based on results from the study.

This study is motivated by the search for the electric dipole moment (EDM) of elementary particles. The most promising idea in that regard is the “Frozen Spin” concept first proposed by the BNL. This concept, however, requires the building of a brand-new facility devoted to the EDM-search. NICA is not such a facility, hence the need for a modification compatible with the existing optics; one that wouldn’t disrupt the ring’s capability for parallel experiments. Such a modification is the “Quasi-Frozen Spin” idea, realized by adding transport channels, bypassing the ring’s straight sections. Wien-filters are placed in these channels in order to compensate spin-rotations caused by the ring’s arc dipoles, thus making its net spin-transfer matrix unitary. Even though, during its movement along the beam line, the beam’s polarization vector deviates from alignment with the momentum vector, this motion is regular and fits within one beam revolution, allowing for the buildup of the EDM-signal. The present study shows that the “Quasi-Frozen Spin”-specific optics is consistent with the existing NICA lattice and that the modified structure is capable of maintaining a requisite spin-coherence time.

The spin-orbital dynamics at the COSY accelerator has been investigated. It has been shown in the numerical experiment that spin-decoherence of the beam is determined by the nonlinear part of the solution of the equation of synchronous acceleration principle. It has been shown that the effects of spin-decoherence are defined by the three parameters of the lattice: horizontal and vertical chromaticity, as well as the nonlinear momentum compaction factor.

This article has been withdrawn by IOP Publishing following the request by the authors to augment their affiliation by an institution. Upon reviewing the matter, IOP Publishing found that the institution (Moscow Institute of Physics and Technology) is subject to sanctions by the UK government. To ensure compliance with sanctions regulations, this article has been withdrawn from IOPscience.

A new experiment to measure electric dipole moments (EDMs) of elementary particles, based on measuring the frequency of the spin precession of a polarized beam, has been proposed for implementation at the NICA facility (JINR, Russia). Polarized beam experiments require long spin-coherence times on the order of 1000 s. The proposed method involves a further complication (enhancing the measurement precision by several orders of magnitude): switching the accelerator guide-field polarity as part of its CW–CCW injection procedure. For the implementation of this latter procedure, a calibration process is necessary, during which the beam polarization axis n changes its orientation from a radial (used in the measurement) to a vertical (used in the calibration) direction. With an adiabatic change in direction, the spin vectors of beam particles follow the direction of the polarization axis, which negatively affects the calibration efficiency. However, if this change is performed nonadiabatically, the question arises on the conservation of the spin coherence of the beam. We address this question in the present investigation.

We propose a system to produce multiple spin reversals of a polarized proton beam based on orbit-steerer dipoles already installed in the Nuclotron, a superconducting synchrotron at the Joint Institute for Nuclear Research, when the latter operates in the spin-transparency regime. The beam momentum of 3.54 GeV/ c corresponds to the integer spin resonance γ G = 7 . We report the results of numerical simulation of the proton spin dynamics pertinent to the acceleration up to γ G = 7 , including the adiabatic capture of spins by navigators and the subsequent multiple spin flips. A feasibility of the pilot experiment to verify our approach with the current magnetic lattice of the Nuclotron is discussed. To preserve the beam polarization during the crossing of integer resonances we propose to employ intentional resonance-strength enhancements effected by controlled variations of the beam orbit during acceleration.

The feasibility of manipulating the beam polarization axis in a spin-transparent storage ring by means of spin-navigating solenoids has been investigated. In particular, deuteron beam spin dynamics in the given lattice and the lattice's properties with respect to beam depolarization via spin decoherence have been considered.

One of the alternatives to the Standard Model (SM) of elementary particles is the supersymmetry theories; the electric dipole moment (EDM) of elementary particles can serve as an excellent tool to confirm the validity of one of these models. For example: in the case of a neutron, the EDM, compatible with the SM, is within a range of $${{10}^{{ - 33}}}$$ to $${{10}^{{ - 30}}}$$ e cm, whereas the supersymmetry theories predict the presence of an EDM of much larger value, at the level of $${{10}^{{ - 29}}}$$ – $${{10}^{{ - 24}}}$$ e cm. Experiments on the search for EDM have been carried out for more than 50 years; however, most of them are based on charge-neutral particles (neutron, atoms). The EDM of charged particles (proton, deuteron) can be measured in a storage ring with the use of the phenomenon of the beam polarization precession in an electromagnetic field. The storage ring has a number of advantages when used as a tool for EDM measurement; however, there are also a number of problems. This paper discusses the main approaches to solving these problems: the BNL, spin wheel, and frequency domain methods.

A new method for searching for the electric dipole moment (EDM) of the deuteron and other nuclei is presented. When trying to measure the EDM in a storage ring environment, magnetic dipole moment (MDM) spin precession due to machine imperfections becomes the primary source of systematic error. The proposed method aims at providing a solution to the machine imperfection problemas well as circumventing the geometric phase error. The method is based on estimating the combined MDM + EDM spin precession frequency, in which the MDM contribution is due only to field imperfections. The MDM term is canceled in the final statistic by adding frequency estimates from cycles with counter-circulating beams. Spin precession rate depends on the particle’s effective Lorentz factor; the proposed method’s core feature is a procedure for equalizing the effective Lorentz factors of the clockwise and counter-clockwise circulating beams, thus enabling the cancelation.

Currently, the "Julich Electric Dipole moment Investigations" (JEDI) collaboration, together with present EDM experiments at the COSY ring, is developing the conceptual design of a ring specifically for the search for the deuteron electric dipole moment (dEDM). One of the main problems in the EDM study is the spin precession in the vertical plane caused by the non-ideal positioning of accelerator elements through the magnetic dipole moment (MDM). The idea of how to separate the EDM from MDM is based on measuring the spin tune in different processes and comparing the results. The high precision of the spin tune measurement is achieved by collecting huge amounts of data. The JEDI collaboration aims at detecting the EDM at a level better than 10(-29) e . cm, for which one requires a precision in the frequency estimate similar to 10(-9) rad/sec. An estimate's statistical precision is conditional on the following factors: the total measurement time, determining the independent variable spread; measurement error; temporal modulation and spacing of sample points. In this paper we analyze the interplay between these factors, and estimate the best achievable precision under given conditions.