RETRACTED: Quasi-frozen spin concept of magneto-optical structure of NICA adapted to study the electric dipole moment of the deuteron and to search for the axion

Abstract

The “frozen spin” method is based on the idea that at certain parameters of the ring, the particle spin rotates with the frequency of the momentum, creating conditions for the continuous growth of the electric dipole moment signal. The Nuclotron-based Ion Collider fAcility (NICA) is under construction in Joint Institute for Nuclear Research [1]. Since a straightforward implementation of the frozen spin regime at NICA is impossible, we suggest an alternative “quasi-frozen spin” concept. In this new regime, the reference particle’s spin-vector precesses with a spin phase advance π ⋅ γG/2 per beam revolution, locally recovering the longitudinal orientation at the location of the electric-magnetic elements, Wien filters, placed in the straight sections. In the deuterons case, thanks to the small magnetic anomaly G, the spin-vector continuously oscillates relative to the direction of the momentum-vector with a small amplitude of a few degrees and the expected EDM effect is reduced only by a few percent. In this paper, we study the spin-orbital motion with the aim of using the NICA collider to measure the EDM. We also comment on the potential of NICA as an axion antenna in both the quasi-frozen spin regime and beyond.