Is there strange-quark matter in galactic cosmic rays?

In the analysis of background events from a counter-technique experiment to study cosmic-ray nuclei above 8-GV rigidity two events were observed which are consistent with the assumption of Z∼14, A∼350, and 450 MeV/nucleon, and which cannot be acocunted for by more conventional background. Such events may be explained by the hypothesis of strange-quark matter (SQM). It is concluded that the existence of SQM has not been excluded by experiment at a flux level of ∼6×${10}^{\mathrm{-}9}$ ${\mathrm{cm}}^{\mathrm{-}2}$ ${\mathrm{s}}^{\mathrm{-}1}$ ${\mathrm{sr}}^{\mathrm{-}1}$.