Study of Polarization Phenomena and Spin Effects

at the JINR Nuclotron-M/NICA Facility

Participating countries and international organizations:

France, Japan, Romania, Russia, Slovakia, Sweden, United Kingdom, USA, Uzbekistan.

The problem under study and the main purpose of the 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.  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 and modernized Delta-Sigma spectrometer is under consideration. 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, 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. 

 Projects:

Brief annotation and scientific rationale:

At present, it is necessary to measure the analyzing powers of protons and neutrons in scattering on CH2, CH and other targets. Such data are necessary for experiments requiring measurements of the polarization of protons and neutrons in nuclear reactions. It also needs optimization hadronic polarimetry and expanding the database on analyzing powers both for protons, the same for neutrons. This is possible only in Dubna, where polarized proton beams and neutrons obtained by fragmentation of accelerated polarized deuterons.

Expected results upon completion of the project:

Investigation of the analyzing powers in the scattering of polarized protons (at momenta up to 7.5 GeV) and neutrons (at momenta up to 6 GeV) on polyethylene, at the ALPOM-2 setup.

Expected results of the project in the current year:

Completion of the modernization of the setup (new drift chambers and a new wide-aperture hadron calorimeter), the beginning of measurements on beams of polarized nucleons.

Brief annotation and scientific rationale:

Study of the structure of 2- and 3-nucleon correlations in the reactions of deuteron-proton elastic scattering and deuteron decay by measuring the tensor analyzing power and spin correlation in dp-scattering reactions in the region of the deuteron nucleus, as well as other processes important for the development theoretical models describing the interactions of the simplest nuclear systems, taking into account relativism and the contribution of the meson and quark-gluon components of the internal motion of components in nucleons. 

Expected results upon completion of the project: 

Measurement of the structure of 2- and 3-nucleon correlations in deuteron-proton elastic scattering and mesonless decay of the deuteron in experiments on the internal target of the Nuclotron. Measurement of cross sections and analyzing powers of these reactions. Performing experiments on control of the proton spin on the internal target of the Nuclotron.

Expected results of the project in the current year:

Completion of the analysis of data on the analyzing powers A_y, A_yy and A_xx of the deuteron-proton scattering at energies
400-1300 MeV. Modernization of the proton polarimeter on the internal target. Publication of the results obtained on polarimetry and on deuteron analyzing powers deuteron-proton scattering up to an energy of 1800 MeV.

Brief annotation and scientific rationale:

The possibility of obtaining beams of accelerated polarized protons in the Nuclotron without significant investment, demonstrated in 2017, became the basis for the intensification of work on the spin program of the NICA project and, in particular, for the development of polarimetry methods, the creation of new methods precise control of the direction of rotation of protons, deuterons and other particles. This part of the work topic is directly related to the creation of the NICA complex and the development of a new approach to management polarization in the spin transparency regime. Of undoubted interest is also the study the possibility of setting up experiments on the collider to measure the EDM and parity violation.

Expected results upon completion of the project:

Development of infrastructure for spin research at the Nuclotron-M/NIKA complex and other installations. Preparation of technical projects for spin control systems and polarimetry. Analysis of the possibility of setting up new experiments with polarized proton beams and deuterons at the NICA complex, in particular on the search for EDM. 

Expected results of the project in the current year:

Creation of a project for the placement of elements of polarimetry for beam diagnostics and polarization control in the SPD section of the NICA collider ring. Completion of the modernization of the polarimeter in the F3 focus. Preparation of terms of reference for the manufacture of a proton polarimeter based on a cluster target.

Collaboration