Speaker
Description
The reactions $np \rightarrow np \pi^+ \pi^-$ was studied at the momenta of incident
neutrons $P_0$=3.83 and 5.20 GeV/c. There were calculated the contributions of various
diagrams (both of one-baryon and one-pion exchages) into the cross-section at the
momenta from the threshold up to 12 GeV/c. It was shown that the main contributions into
the reaction $np \rightarrow np \pi^+ \pi^-$ at the momenta above $P_0>$3 GEV/c
are provided by the diagrams of the reggeized $\pi$~exchange model (OPER).
The reeaction $np \rightarrow np \Delta^{++} \Delta^-$ was selected to study the spin
effect for $\Delta$-resonance decay. It was shown that the satisfactory description of
spin density matrix [$\rho_{ij}$] could be provided taking into account the diagram
of $\rho$-meson exchange. The reaction $np \rightarrow np \rho^0$ was selected using
the background subtraction. The study showed that the observed $\rho^0$ production is
provided by the 'hanged' diagram of OPER-model.\
The obtained results are in agreement with world data.
