Search for fractionally charged nuclear fragments in relativistic heavy ion collisions

We have investigated about 11000 fragments with charge 6{le}{ital Z}{le}10 produced by 200 GeV/nucleon {sup 32}S projectiles and about 11000 fragments with charge 6{le}{ital Z}{le}10 produced by 10.6 GeV/nucleon {sup 197}Au projectiles. Charges were measured using stacks of CR-39 plastic nuclear track detector foils. By multiple measurements on the surfaces of adjacent detector foils a charge resolution sufficient to identify fragment charges {ital Z}{plus_minus}1/3 could be achieved over a minimum track length of a few mm. We found no evidence for a fast fragment with a charge differing from an integer by as much as 1/3. {copyright} {ital 1996 The American Physical Society.}