A Search for Lightly Ionizing Particles with the MACRO Detector
  A search for lightly ionizing particles has been performed with the MACRO detector. This search was sensitive to particles with charges between $\fractional{5}$$e$ and close to the charge of an electron, with $\beta$ between approximately 0.25 and 1.0. Unlike previous searches both single track events and tracks buried within high multiplicity muon showers were examined.   In a period of approximately one year no candidates were observed. Assuming an isotropic flux, for the single track sample this corresponds to a 90% C.L. upper flux limit $\Phi \leq 9.2 \times 10^{-15} cm^{-2} sec^{-1} sr^{-1}$ . 
MACRO Collaboration