ISOSPIN DEPENDENCE OF THE η' MESON PRODUCTION IN NUCLEON-NUCLEON COLLISIONS

A comparison of the close-to-threshold total cross section for the �' production in pp → pp�' and pn → pn�' reactions constitutes a tool to investigate the �' me- son structure and the reaction mechanism in the channels of isospin I = 0 and I = 1 and may provide insight into the flavour-singlet (perhaps also into gluonium) content of the �' meson. In this contribution we present preliminary results of measurement of the quasi-free pro- duction of the �' meson in the proton-neutron collisions conducted using the COSY-11