Search for Nonintegrally Charged Projectile Fragments in Relativistic Nucleus-Nucleus Collisions

Using dioctyl-phthalate-doped CR-39 plastic track detectors with charge resolution ${\sigma }_Z\approx 0.06e$, the authors have made the first dynamic search for fractionally charged particles bound to nuclei. They find, from charge measurements in the first ∼ 2 cm after production, that no more than 3 × ${10}^{-3\mathrm{}}$ (95% confidence level) of the projectile fragments of 1.85-GeV/u ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ar}$ interactions with $10<~Z<\mathrm{}18\mathrm{}$ have charges differing from an integer by as much as $0.3e$. This rules out explanations of anomalons based on models in which the anomalons have nonintegral charge in such charge range.