Forty-year anniversary: bottom quark discovery announcement

Forty years ago today, on June 30, 1977, scientist Steve Herb gave the official announcement at a seminar of the findings of E288, namely, the discovery of the upsilon particle. E288 was an experiment in the proton fixed-target area led by Leon Lederman and made up of scientists from Columbia University, Fermilab and the State University of New York at Stony Brook. The experiment sought to study the rare events that occur when a proton beam collides with a platinum target, producing a pair of muons or electrons. The experimenters observed a bump in the number of events at 9.5 GeV, indicating the existence of the upsilon particle, which was later understood to be the bound state of the bottom quark and its antiquark.

E288 experimenters. Left image (L to R): D. Hom, C. Brown, A. Ito, R. Kephart, K. Ueno, K. Gray, H. Sens, H. D. Snyder, S. Herb, J. Appel and D. Kaplan. Right image: J. Yoh (seated), L. Lederman.

The experiment began with a proposal for E70, which was submitted on June 17, 1970. The third phase of E70 ultimately became E288. The experimenters began taking data for E288 on May 15, 1977. A fire in the Proton Center pit on May 22 briefly delayed the experiment, but the group was able to resume operations on May 27. By June 15, the experimenters were confident in their results, and Steve Herb announced the discovery at a June 30 seminar in the Fermilab Auditorium. Experimenters at Fermilab would go on to discover its partner the top quark in 1995.

The Fermilab Archives contains extensive records of the discovery. You can read more about the discovery of the bottom quark at the Fermilab History and Archives Project Web page devoted to the event, which includes a special edition of The Village Crier from the summer of 1977 announcing the discovery, internal notes of the collaboration provided by John Yoh and many other materials.

Read the press release on the announcement. Check out also a logbook entry from one of the co-discovers, John Yoh, when he first noticed the bump that would turn out to be the Upsilon.

As a tribute to the 40th anniversary of the bottom quark discovery, we offer a celebratory cover of the fictional BQ magazine.