The dimensional scaling of the differential cross sections of binary reactions $dsigma/d tsim s^{-(n-2)}$, where $n$ is given by constituent quark counting rules, was predicted for asymptotically high energies $sqrt{s}gg m_i$ and transferred momenta $-tgg m_i^2$ at $t/s=const$ (here $s$ and $t$ are the Mandelstam variables and $m_i$ denotes a hadron mass), but manifested itself at surprisingly moderate energies of few GeV at large fixed cms angles $theta_{cm}sim 90^circ$. This behaviour is observed not only in reactions with free hadrons, but with the deuteron and $^3He$ too both for electromagnetic and pure hadronic interactions. One may suppose that observed scaling points out to effective restoration of near-conformal and, probably, chiral symmetry in these processes. A systematical experimental study of the scaling behaviour of the reactions with the deuteron, $^3H$, $^3He$, and $^4He$ nuclei is still absent. We consider a possibility to carry out this study in $dd$ collisions at the JINR Nuclotron.
The integrated cross section $widetildesigma$ for a special type of double polarized proton-deuteron scattering constitutes a null test forvtime-invariance violating but P-parity conserving effects. Using the Glauber theory for the $pd$ elastic scattering and different types of phenomenological T-odd P-even NN-interactions we show that the contribution of the lowest mass meson exchange, i.e. the $rho$-meson, to the null-test signal $widetildesigma$ vanishes. Variation of the cross section $widetildesigma$ due to strong hadronic and Coulomb interaction is studied and its energy dependence is calculated in the GeV region.
Mechanisms of the charge exchange reaction $dpto {pp}_{!s} Npi$, where ${pp}_{!s}$ is a two-proton system at low excitation energy, are studied at beam energies 1 -- 2 GeV and for invariant masses $M_X$ of the final $Npi $ system that correspond to the formation of the $Delta(1232)$ isobar. The direct mechanism, where the initial proton is excited into the $Delta(1232)$, dominates and explains the existing data on the unpolarized differential cross section and spherical tensor analyzing power $T_{22}$ for $M_X> 1.2$ GeV/$c^2$. However, this model fails to describe $T_{20}.
Antiproton scattering off $^3He$ and $^4He$ targets is considered at beam energies below 300 MeV within the Glauber-Sitenko approach, utilizing the $bar N N$ amplitudes of the Julich model as input. A good agreement with available data on differential $bar p ^4He$ cross sections and on $bar p ^3He$ and $pbar ^4He$ reaction cross sections is obtained. Predictions for polarized total $bar p ^3$He cross sections are presented, calculated within the single-scattering approximation and including Coulomb-nuclear interference effects. The kinetics of the polarization buildup is discussed.
A formalism for spin observables of the reaction $pdto ~^3Heeta$ is derived in a model independent way. The general case with a full set of six independent spin amplitudes is studied. Furthermore, approximations by five and four spin amplitudes are investigated in the near threshold region. This region is of great interest to search for a quasi-bound $^3He-eta$ state, in particular, by measurement of energy dependence of relative phases of s- and p-wave amplitudes. Complete polarization experiments, allowing determination of spin amplitudes, are analyzed. It is shown that measurement of only analyzing powers and spin correlation coefficients hardly allows one to separate the s- and p-wave amplitudes, but additional measurement of polarization transfer coefficients simplifies this problem. Specific observables, given by products of one s- and one p-wave amplitudes, are found. Measurement of these observables will provide new independent information on the $^3He-eta$ pole position.
