Brookhaven National Lab and the Nobel Prize
Photo of CP detection equipment

Detection equipment used in the CP violation experiment at the AGS beam line.

CP Violation

In 1980, the physics Nobel went to two researchers whose discovery at Brookaven's Alternating Gradient Synchrotron (AGS) was the opposite of what they had expected to find when they began their experiment in 1963.

James W. Cronin and Val L. Fitch, both then of Princeton University, proposed using Brookhaven's AGS to verify a fundamental tenet of physics, known as CP symmetry, by showing that two different particles did not decay into the same products. They picked as their example neutral K mesons, which are routinely produced in collisions between a proton beam and a stationary metal target.

The experiment set out to show that in millions of collisions, the short-lived variety of K meson always decayed into two pi mesons, while the long-lived variety never did. But to their surprise, a "suspicious-looking hump" in the data showed an unexpected result that years of subsequent experimentation and theory have been unable to explain: occasionally, the long-lived neutral K meson does decay into two pi mesons. Cronin and Fitch had found an example of CP violation.

The discovery's ramifications stretched far beyond the neutral K mesons; Cronin and Fitch had discovered a flaw in physics' central belief that the universe is symmetrical.

Val Fitch was actively involved with the Board of Trustees of Associated Universities, Inc., which managed Brookhaven Lab for the U.S. Department of Energy from 1947 to 1997. From 1961-1967, and 1988-1991, he was a trustee; from 1991-1993, he served as Chairman of the Board; and in 1993, he returned to the Board as a member.