Abstract

CDF (the acronym stands for Collider Detector at Fermilab) is the experiment that in 1994 and 1995 suggested and then confirmed the discovery of the top quark, using 1.8 TeV collisions of protons with antiprotons at the Fermilab Tevatron. To assemble convincing evidence for the top quark, the CDF group collected data from a large number of proton-antiproton collisions during the 1992-93 running period. Then, with the top quark safely salted away, the CDF group has been examining their accumulated data for other aspects of the p+p-bar collisions. One such study of the CDF group focuses on "jets" from the p+p-bar collisions. "Jet" is high-energy physics jargon for a cluster of high energy particles emitted in the same direction. Free unattached quarks are not permitted by the rules of QCD. Within the colliding protons, the constituent quarks are tied together with gluons that form "color strings" connecting the quarks. If a quark strikes another quark in a head-on collision and is ejected from its surrounding proton, its attempted escape from this confinement stretches the string until it breaks, with a new quark and anti-quark forming at the broken string ends. The resulting multitude of new quarks combine to form a multitude of new particles, all moving in the same direction as the original quark, thereby forming a "jet". When a very high energy quark is ejected from a collision, a jet is what actually reaches the detector