Search for bound states of negative pions and neutrons in relativistic heavy-ion reactions

An experimental search for bound systems of {pi}{sup {minus}}'s and neutrons (pineuts) was made in collisions of {sup 40}Ar (1.8{ital A} GeV) and {sup 139}La (1.3{ital A} GeV) projectiles on a {sup 238}U target. Five candidate events survived the selection criteria but--in view of their marginal systematic consistency--they are not taken as valid evidence for pineuts. Upper limits for production cross sections are derived for singly and doubly charged systems on the order of 4{times}10{sup {minus}35} cm{sup 2}/sr(MeV/{ital c}).