Number 165 (Story #1), February 17, 1994 by Phillip F. Schewe and Ben Stein LEPTOQUARKS HAVE NOT BEEN FOUND at the Tevatron. Certain theories seeking to unify the electromagnetic, weak, and strong forces hold that in addition to the known families of elementary particles---the quarks and the leptons---there should exist another family, the leptoquarks, which would have both lepton and quark-like attributes. Scientists using the D0 detector at the Tevatron proton-antiproton collider have sought in vain for evidence of leptoquarks in interactions at the highest energy available at any accelerator, 1.8 TeV. If they had existed within an accessible mass range, leptoquarks would have been produced in pairs; each would have decayed into an electron and a quark. From the data, the Tevatron scientists estimate a lower limit on the leptoquark mass of 133 GeV. As if to illustrate the massiveness of the undertaking of finding a new class of fundamental particles, the published paper bears the names of 351 authors. (S. Abachi et al., 14 February 1994, Physical Review Letters.)