Search for Stable Strange Quark Matter in Lunar Soil using the Mass   Spectrometry Technique
  Strange quark matter is a postulated state which may be the true ground state of cold hadronic matter. Physicists have been searching for strange quark matter in the last several decades but found no definite evidence of its existence. In our experiment, we used the Yale tandem accelerator as a mass spectrometer to identify possible stable strangelets (small chunks of strange quark matter) in lunar soil. The search covers the mass range from A=42 to A=70 amu for nuclear charges 6, 8, and 9. No strangelets are found at sensitivity levels down to $\sim10^{-17}$. The implied limit on strangelet flux in cosmic rays is the most sensitive to date for the covered mass range. 
Ke Han (for the LSSS Collaboration)