Search for highly ionizing particles ine+e−collisions ats=29GeV

The results of the analysis of data taken in the continuation of a previously reported search for highly ionizing particles at PEP are presented. Assemblies consisting of Lexan and CR-39 plastic track detectors were exposed in two runs to integrated luminosities of 30×${10}^{36}$ ${\mathrm{cm}}^{-2\mathrm{}}$ and 150×${10}^{36}$ ${\mathrm{cm}}^{-2\mathrm{}}$. The search was sensitive to particles with magnetic charge $20e<~g<~200e$ or electric charge $3<~Z<~180$. A combined (95% C.L.) upper limit on the production cross section of $\sigma <3.2\mathrm{}\times {10}^{-38\mathrm{}}$ ${\mathrm{cm}}^2$ is obtained, improving our previous limits by more than an order of magnitude.