Nucleus-Nucleus Collisions at Low Energies. The Effects from Non Vacuum Exchange

Experimental data on total and differential elastic cross sections for $p+p(\bar{p})$, $n+p(\bar{p})$, $K^\pm+p$, $K^\pm+n$, $\pi^\pm+p$ starting from energy 3.5 GeV in CMS are used to determine parameters of vacuum contribution and parameters of basic non vacuum reggeons: $f$, $\omega$, $\rho$ and $A_2$. It is argued that non vacuum contributions to proton-proton and proton-neutron collisions correspond to spectrum in which baryon number is moved from the fragmentation region to central region in rapidity space. In this case it is possible that chemical potential is increased in central region of spectrum of nucleus-nucleus interaction at low energies. This effect might be important for facilities FAIR and NICA.