Arizona, Chicago, Colorado, Elmhurst, Fermilab, Osaka,
Rice, Rutgers, UCLA, UCSD, Virginia, Wisconsin

Continuing research interests of our collaboration members (some 80 physicists and 12 institutions) include the study of fundamental symmetries, rare decay processes, weak interactions, and polarization phenomena. A striking asymmetry of our world is the fact that the universe appears to be composed entirely of matter and no astronomical object made of anti-matter has ever been detected. In fact, the only anti-matter we find anywhere is minute quantities produced in high energy particle interactions like those studied here at the Fermi National Accelerator Laboratory (Fermilab).

We know only one other place where an asymmetry of this kind formally called "CP violation" has been observed. This is a tiny effect (about 1 part in 500) in certain decays of a particular elementary particle called the neutral Kaon. As always, intellectual progress is most likely to occur when exploring the limits of established ideas. Thus our current Fermilab experiments seek to determine whether or not this effect can be fully understood in the context of the present picture of matter (the "Standard Model"). We go by the name "KTeV" for "Kaons at the TeVatron."

To do this we are performing high-precision measurements on decays which are known to manifest CP violation and studying a variety of extremely rare decay processes. Both require large numbers of neutral Kaons. These are produced by the world's highest energy proton beam from Fermilab's TeVatron accelerator. Then fast, precise position and energy measurements are necessary for both electrically and neutral particles arising from the decays. The KTeV experimental apparatus thus consists of a tandem series of state-of-the-art detectors to do this and to help us identify the types of particles emerging from the decays. Data from the detectors are organized, monitored, displayed, culled, and recorded on magnetic tape by programs running on a powerful 34-processor on-line computer system.

A 15-month data collection period ("fixed target run") has just ended. Though this required a 24-hour/day effort, we also managed to perform some preliminary data analysis during this time. We have already discovered two new decay processes which had never before been seen and are systematically studying them. Now that our attention is focused on data analysis, many new results will emerge. These investigations are particularly exciting because they provide a great variety of alternative windows on CP violation and other phenomena with extraordinary potential to enhance our understanding of nature.

E.S., September, 1997