Search for Charged Strange Quark Matter Produced in11.5AGeV/cAu+PbCollisions

We present results of a search for strange quark matter (strangelets) in $11.5A\mathrm{GeV}/c\mathrm{Au}+\mathrm{Pb}$ collisions from the 1994 and 1995 runs of experiment E864 at Brookhaven's Alternating Gradient Synchrotron. We observe no strangelet candidates and set a 90% confidence level upper limit of approximately $3\times {10}^{-8\mathrm{}}$ per 10% central interaction for the production of $|Z|=1\mathrm{}$ and $|Z|=2\mathrm{}$ strangelets over a large mass range and with metastable lifetimes of about 50 ns or more. These results place constraints primarily on quark-gluon plasma based production models for strangelets.