Study of Polarization Phenomena and Spin Effects
at the JINR Nuclotron-M/NICA Facility

Participating countries and international organizations:

Bulgaria, Czech Republic, France, Germany, Japan, Poland, Romania, Russia, Slovakia, Sweden, United Kingdom, USA, Uzbekistan.

Issues addressed and main goals of research:

Polarization studies are undoubtedly relevant now. They combine the efforts of the JINR Laboratories and many foreign laboratories, both participating and non-participating countries, in the design and conduct of experiments using unique beams of polarized deuterons with energies ranging from 5 MeV per nucleon to 5.6 GeV/n, secondary beams of polarized protons and neutrons, as well as beams of polarized protons directly accelerated in the Nuclotron. The possibility of obtaining beams of accelerated polarized protons in the Nuclotron without significant investment, demonstrated in 2017, became the basis for intensifying work on the spin program of the NICA project and, in particular, for the development of polarimetry techniques, the creation of new methods for precise control of the direction of the spin of protons, deuterons and other particles. This part of the work on the topic is directly related to the creation of the NICA complex and the testing of a new approach to controlling the polarization in the spin transparency mode. Of undoubted interest is also the study of the possibility of setting up experiments at the collider to measure EDM and parity violation. The most important scientific and methodological direction of work within the framework of the topic is the development of infrastructure for conducting research with polarized beams, namely: the creation and development of systems for polarimetry and spin direction control. At the forthcoming stage of work, due to the concentration of efforts on the implementation of the NICA project, this component also has the first priority. Within the framework of the theme, two projects are being carried out: ALPOM-2 and DSS. Preparation of the project on spin effects measurements in nucleon-nuclear scattering with using Movable Polarized Target Saclay-ANL-JINR (MPT) and Delta-Sigma and Delta-2 spectrometers. Extension proposals for these projects for 2019-2023. were reported at the STC VBLHEP in April 2021 and approved with a recommendation to assign the first priority to these works. Taking into account the presence of polarized beams, new experimental data will be obtained on the study of charge-exchange processes, on the study of the structure of 2- and 3-nucleon correlations in the reactions of deuteron-proton elastic scattering and deuteron breakup (experiments on the internal target of the Nuclotron), by measuring tensor analyzing power and spin correlation in the dp scattering reaction in the deuteron core region, as well as other processes that are important for the development of theoretical models describing the interactions of the simplest nuclear systems with allowance for relativism and the contribution of the meson and quark-gluon components of the internal motion of constituents in nucleons.

Expected results in the current year:

1. Works:
   a) testing a low-energy polarimeter for protons and deuterons on the injection channel into the Nuclotron;

b) designing a polarizing helium-3 target;

c) modernization of the polarimeter at focus f3.

2. Carrying out work on approved projects and agreements, taking into account their resource availability, including ALPOM-2 and DSS projects.  Completion of the data analysis on the analyzing powers A_y, A_yy and A_xx in deuteron-proton elastic scattering at the energies 400-1300 MeV. Publication and reports of the results.

3. Creation of a project for the placement of polarimetry elements for beam diagnostics and polarization control at the SPD section of the NICA collider ring.

4. Modernization of the MPT. Preparation of the Delta-Sigma and Delta-2 spectrometers. Carrying out calculation and design work on detector around target (DTS).

5. Continuation of the development of new calculation methods of the amplitudes and polarization characteristics of deuteron fragmentation and deuteron elastic scattering on protons and nuclei taking into account FSI and relativistic effects.

6. Analysis of the possibility of staging new experiments with polarized beams of protons and deuterons at the NICA complex, in particular, on the search for EDM.

Collaboration