Search for Strange-Pentaquark Production in e+e- Annihilation at √s=10.58 GeV and in Upsilon(4S) Decays

We search for strange pentaquark states that have been previously reported by other experiments --the Θ(1540)+, Ξ(1860)2, and Ξ5(1860)0--in 123 fb-1 of data recorded with the BABAR detector at the PEP-II e+e- storage ring. We find no evidence for these states and set 95% confidence level upper limits on the number of Θ(1540)+ and Ξ5(1860)2 pentaquarks produced per e+e- annihilation into q(bar q) and per Υ(4S) decay. For q(bar q) events these limits are about eight and four times lower, respectively, than the rates measured for ordinary baryons of similar mass