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

A comparison of the close–to–threshold total cross section for the η' production in pp → ppη' and pn → pnη' reactions constitutes a tool to investigate the η' meson 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 η' meson. In this contribution we present preliminary results of measurement of the quasi-free production of the η' meson in the proton-neutron collisions conducted using the COSY-11 facility.