Fermilab Tevatron Collider Group Goes Over the Top—Cautiously

The evidence from Fermilab’s Collider Detector Facility group for a $\text{174‐}\mathrm{GeV}{\mathrm{/c}}^2$ top quark (see PHYSICS TODAY, May, page 20) has been received with cautious enthusiasm by the particle physics community. Since most physicists still have not seen the 153‐page preprint submitted on 22 April to Physical Review D, the demand for speakers on the result exceeds even CDF’s abundant supply of experimenters. Still, it is unlikely that new developments will suppant CDF’s present results before we’ve had time to digest them. the low top‐production rate, the large backgrounds—events that mimic top decay—and the complicated topologies of t‐quark decays all but ensure that the discovery of the t quark will be a protracted process rather than a single dramatic event. While awaiting new results from CDF and DO (the other detector at Fermilab’s 1.8‐TeV pp̄ collider), it is appropriate to evaluate CDF’s present evidence and to anticipate possible future developments.