SPD (NICA)
The Spin Physics Detector is a planned experimental setup at the NICA collider is intended to study the spin structure of the proton and deuteron and the other spin-related phenomena with polarized proton and deuteron beams at a collision energy upto 27 GeV and a luminosity up to $10^{32}$ $сm^{-2}$ $с^{-1}$.
In the polarized proton-proton collisions, the SPD experiment will cover thekinematic gap between the low-energy measurements at ANKE-COSY and SATURNE and the high-energy measurements atthe Relativistic Heavy Ion Collider, as well as the planned fixed-target experiments at the LHC. As for the possibility forNICA to operate with polarized deuteron beams at such energies, it is unique. SPD is planned to operate as a universal facility for comprehensive study of the unpolarized and polarized gluon content of the nucleon at large and moderate x, using different complementary probes such as: charmonia, open charm, and prompt photon production processes. A priority of the experiment is the measurement of parton distributions depending on the transverse momentum of partons in the nucleon (TMD PDFs). The study of spin effects in the elastic scattering of protons and deuterons, and in the production of lambda-hyperons, search for dibaryon resonances, study of the charmed particles production near threshold, study of multiquark correlations, and other polarized and unpolarized physics will be available at the first stage of the collider operation withreduced luminosity and collision energy of proton and ion beams.
Expected results upon completion of the project
The main result of the experiment should be new information on the gluon helicity, gluon Sivers, Boer-Mulders and other Transverse Momentum Dependent PDFs in the nucleon, as well as the gluon transversity distribution and tensor PDFs in the deuteron, via the measurement of specific single and double spin asymmetries. The results expected to be obtained by SPD will play an important role in the general understanding of the properties of strong interaction, specifically, of the nucleon gluon content and will serve as a complementary input to the ongoing and planned studies at RHIC, and future measurements at the EIC (BNL) and fixed-target facilities at the LHC (CERN). Simultaneous measurement of the same quantities using different processes at the same experimental setup is of key importance for minimization of possible systematic effects.
