Limits on quark-lepton compositeness scales from dileptons produced in 1.8 TeV $p\bar{p}$ collisions

The dilepton mass spectrum in p{bar p}{r_arrow}l{sup +}l{sup {minus}}+X interactions is studied using dielectrons ({ital ee}) and dimuons ({mu}{mu}) in 110 pb{sup {minus}1} of data collected with the Collider Detector at Fermilab. The data are consistent with standard model predictions. The mass spectrum, being a probe for new physics, is examined for new interactions of quarks and leptons from a common composite structure. Assuming a contact interaction with the conventional coupling g{sup 2}{sub 0}/4{pi}=1 , limits on chiral quark-electron and quark-muon compositeness scales in the range of 2.5 to 4.2TeV are obtained. {copyright} {ital 1997} {ital The American Physical Society}