Nuclotron based Ion Collider fAcility (NICA) project is in progress at the Joint Institute for Nuclear Research and will start experiments with heavy ions. In the context of the NICA hadronic physics programme double polarized \(pp\)-, \(dd\)- and \(pd\)-collisions even at lower energies of \(\sqrt {{{s}_{{NN}}}} = 3.4{\kern 1pt} - {\kern 1pt} 10\) GeV, which will be accessible already at the initial stage of experiments,are essential tools for precise studying the spin dependence of the nucleon–nucleon strong interactions, in both elastic and deep-inelastic regimes. A special interest is interaction in few baryon systems at double strangeness, charm and beauty thresholds.For instance, polarized large-angle elastic \(pp\) and \(pn\) scattering near the charm threshold allows one to get an access to properties of possible exotic multiquark states and their relation to the states recently observed at LHCb.Large angle scattering of protons and deuterons on the deuteron contains unique information on the short-range structure of the deuteron, its nonnucleonic degrees of freedom and also on color transparency phenomenon. Furthermore, double polarized proton–deuteron scattering offer a possibility to test the Standard Model through the search for time-invariance (or CP-invariance under CPT symmetry) violation and parity-violation in single-polarized scattering. This paper contains suggestions for experiments with usage of the Spin Physics Detector (SPD) and discusses perspectives of the first stage of the SPD Programme. This includes experiments with nonpolarized beams too as well as collisions like ¹²С–¹²С and ⁴⁰Сa–⁴⁰Ca.

We have recently highlighted the presence of a periodically oscillating 10% modulation in the BABAR Collaboration data on the proton timelike form factors, expressing the deviations from the pointlike behavior of the proton-antiproton electromagnetic current in the reaction $e^{+}+e^{-}\to \overline{p}+p$. Here we deepen our previous data analysis and confirm that in the case of several standard parametrizations it is possible to write the form factor in the form $F_0+F_{\mathrm{osc}}$, where $F_0$ is a parametrization expressing the long-range trend of the form factor (for $q^2$ ranging from the $\overline{p}p$ threshold to 36 ${\mathrm{GeV}}^2$), and $F_{\mathrm{osc}}$ is a function of the form $exp(-Bp)cos\left(Cp\right)$, where $p$ is the relative momentum of the final $\overline{p}p$ pair. Error bars allow for a clean identification of the main features of this modulation for $q^2<10{\mathrm{GeV}}^2$. Assuming this oscillatory modulation to be an effect of final-state interactions between the forming proton and the antiproton, we propose a phenomenological model based on a double-layer imaginary optical potential. This potential is flux absorbing when the distance between the proton and antiproton centers of mass is $\gtrsim 1.7–1.8$ fm and flux generating when it is $\lesssim 1.7–1.8$ fm. The main features of the oscillations may be reproduced with some freedom in the potential parameters, but the transition between the two layers must be sudden (0–0.2 fm) to get the correct oscillation period. The flux-absorbing part of the $\overline{p}p$ interaction is well known in the phenomenology of small-energy antiproton interactions and is due to the annihilation of $\overline{p}p$ pairs into multimeson states. We interpret the flux-creating part of the potential as due to the creation of a $1/q$-ranged state when the virtual photon decays into a set of current quarks and antiquarks. This short-lived compact state may be expressed as a sum of several hadronic states including the ones with large mass $Q_n\gg q$, that may exist for a time $t\sim 1/(Q_n-q)$. The decay of these large-mass states leads to an intermediate-stage regeneration of the $\overline{p}p$ channel.

The possible contribution of two-photon exchange to electron deuteron elastic scattering at relatively high momentum transfer is discussed. This study was motivated by the high precision data recently obtained at the Jefferson Laboratory. Using general arguments, based on crossing symmetry for the processes $e^{-}+\overrightarrow{h}{e}^{-}+h$ and $e^{+}{+e}^{-}\to h+\overline{h},$ we find a parametrization for the angular dependence of the interference between the one- and two-photon exchanges in the differential cross section for elastic $\mathrm{ed}$ scattering in terms of a new kinematical variable and compare our findings to the recent data.