Search for strangelets in Pb + Pbcollisions at 158 A GeV/c

Abstract

The NA52 experiment at CERN has investigated lead-leadcollisions at 158 A GeV/c and searched for long-livedstrange quark matter droplets, so-called strangelets, with aunique signature of a high mass-to-charge ratio. This ratio wasmeasured in a focusing spectrometer equipped with a time-of-flight system. A total of 3×1011 Pb + Pbinteractions at positive and 1013 at negative spectrometerpolarities have been recorded. No strangelet has been observed,which sets experimental upper limits (90% CL) for thestrangelet production at 3×10-9 per interaction forpositively charged and at 2×10-10 per interaction fornegatively charged strangelets.