Search for scaling onset in exclusive reactions with the lightest nuclei

Abstract

The dimensional scaling of the differential cross sections of binary reactions $d\sigma /dt\sim s^{-(n-2)}$, where $n$ is given by constituent quark counting rules, was predicted for asymptotically high energies $\sqrt{s}\gg m_i$ and transferred momenta $-t\gg m_i^2$ 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 ${}^{3}He$ 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, ${}^{3}H$, ${}^{3}He$, and ${}^{4}He$ nuclei is still absent. We consider a possibility to carry out this study in $dd$ collisions at the JINR Nuclotron.

Comments: 5 pages, 3 eps-figures, accepted by the European Physical Journal A