We search for new particles that decay into b¯b and are produced with W bosons in p¯p collisions at √s=1.8TeV. The search uses 109±7pb⁻¹ accumulated by the CDF experiment at Fermilab. We select events with an eν or μν, and two jets, one of them b tagged. The number of events and the two-jet mass distribution are consistent with expectations. Using W+Higgs production as a model for the acceptance, we set an upper limit on the production cross section times branching ratio for the new particle ranging from 14 to 19 pb (95% C.L.) as the particle mass varies from 70 to 120GeV/c².