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

Abstract

Using dioctyl-phthalate-doped CR-39 plastic track detectors with charge resolution ${\ensuremath{\sigma}}_{Z}\ensuremath{\approx}0.06e$, the authors have made the first dynamic search for fractionally charged particles bound to nuclei. They find, from charge measurements in the first \ensuremath{\sim} 2 cm after production, that no more than 3 \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}3}$ (95% confidence level) of the projectile fragments of 1.85-GeV/u $^{40}\mathrm{Ar}$ interactions with $10<~Z<18$ 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.