On problem of pion and neutron bound state

The problem of existence of the bound states of negativ pions and neutrons has been widely discussed for the last years. In this paper possibilities of the experimental observation of pion-neutron clusters, if they do exist, in nucleus-nucleus collisions are considered. The yields of exotic fragments π-ZnA in the interactions of 12C and 56Fe with 208Pb at the energies from 0.3 to 3.7 GeV per nucleon are calculated. For 40Ar+238U and 139La+238U collisions, the calculations were performed at the energies of 1.8 GeV and 1.3 GeV per nucleon respectively. These calculations were performed in the framework of the coalescence mechanism with the differential cross sections for pion and neutron production generated by the firestreak model. The differential cross sections for production of π-1n2, π-2n2, π-2n4, π-4n6, and π-12n6 were calculated. It is shown that the use of very heavy projectiles like 56Fe and 139 La has a great advantage in the experimental search for the exotic clusters