The dilepton mass spectrum in $p\overline{p}\to l^{+}{l}^{-}+X$ interactions is studied using dielectrons (ee) and dimuons (μμ) in $110{\mathrm{pb}}^{-1\mathrm{}}$ 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 $g_0^2/4\mathrm{}\pi =1\mathrm{}$, limits on chiral quark-electron and quark-muon compositeness scales in the range of 2.5 to 4.2 TeV are obtained.

• Received 30 May 1997

DOI:https://doi.org/10.1103/PhysRevLett.79.2198