Recent investigations have suggested that the six-quark combination uuddss could be a deeply bound state (S) that has eluded detection so far, and a potential dark matter candidate. We report the first search for a stable, doubly strange six-quark state in Υ→S ̄Λ ̄Λ decays based on a sample of 90×106Υ(2S) and 110×106Υ(3S) decays collected by the BABAR experiment. No signal is observed, and 90% confidence level limits on the combined Υ(2S,3S)→S ̄Λ ̄Λ branching fraction in the range (1.2–1.4)×10−7 are derived for mS<2.05 GeV. These bounds set stringent limits on the existence of such exotic particles.
