Formation of light antinuclei and "dense gas" stage in heavy ion collisions

The antideuteron and antihelium-3 production rates at high-energy heavy ion collisions are calculated in the framework of fusion mechanism. It is supposed, that p¯,n¯,d¯,H¯e3 participating in the fusion are moving in the mean field of other fireball constituents. It is demonstrated that at the "dense gas" stage of fireball evolution, preceding the thermal freeze-out, the coalescence parameters for d¯ and H¯e3 can be found from the requirement of balance between created and disintegrated antinuclei. The explicit formulae for coalescence parameters are presented and compared with the data.