Search for neutral strangelets at the relativistic heavy ion experiment E864

We report on the first search for neutral strange quark matter in Au+Pb reactions at 11.6 A GeV/c in experiment E864 at the Brookhaven National Laboratory AGS. We have sampled approximately 1.3 billion 10% most central Au+Pb interactions and have observed no evidence for the production of neutral strangelet states with a baryon number in the range 3<A<100. We thus set production limits at the level of 8x10-8 for these exotic objects in the mass range 15<A<100, and limits between 10-4 and 10-7 in the mass range 3<A<15. These limits are rather insensitive to the details of production models thanks to the large acceptance of the E864 spectrometer. The limits for neutral strangelets reported in this work complement other limits reported by our collaboration for positive and negative strangelets (Xu Z 1999 J. Phys. G: Nucl. Part. Phys. 25 403, Van Buren G 1999 J. Phys. G: Nucl. Part. Phys. 25 411). (author)