Truemanfest
By Sally Dawson
On Monday, May 12, 2008, the BNL Physics Department and colleagues gathered to celebrate the retirement of Larry Trueman with a symposium. The symposium featured talks on the history of spin physics at BNL, along with talks by many of Larry’s collaborators. Larry worked at BNL for 46 years in a variety of roles. A particle theorist, he served at various times as the high energy theory group leader, Physics Department associate chair for high energy physics, and associate laboratory director for high energy and nuclear physics. As of April 1, 2008, he is a senior emeritus scientist with the high energy theory group.
High energy theory has changed dramatically during Larry’s
time at BNL. During the 1960’s, the high energy theory group
consisted of Trueman and Peierls, along with 6 post-docs. One of
these post-docs, Al Mueller, described the BNL discoveries of
this era. The landmark experiments--the two neutrino experiment,
the Ω− discovery and the discovery of CP violation are well
known--but at this time theoretical physics at BNL was also
thriving. Mueller described the classic paper of Trueman and
Wick in 1964. which set up the formalism for describing the
strong interactions using helicity amplitudes and crossing
symmetry. This formalism is necessary for understanding spin and
marked the beginning of the spin effort at BNL. Soon after, the
study of the spin dependence of high energy scattering
amplitudes by Mueller and Trueman appeared.
The spin story at BNL continued with the work of Trueman and Leader who focused in the early years on the power of spin in testing theories of the strong interaction and in determining the structure of hadronic interactions. The emphasis then was on trying to understand the structure of scattering amplitudes and from this the hope was to understand the dynamics of the theory. As described by Leader, real theoretical progress had to wait for the polarized proton experimental program. The experimental history of the spin program at BNL was reviewed by Gerry Bunce. The story started with the polarized proton program at the AGS in the mid-80’s and was galvanized by the EMC “proton spin crisis”. With the advent of the spin program at RHIC, spin physics took another step forward. The experiments needed to know the polarization of the high energy proton beams to high accuracy. Trueman and his collaborators developed a technique using carbon-nucleon interference which has been successfully used to measure the polarization at RHIC. Kopeliovich described one application of spin physics at RHIC—the attempt to understand the single spin asymmetry of forward neutrons.
During the 1980’s, Trueman’s interests moved to the calculation of W and jet production in hadronic collisions, with a focus on physics at ISABELLE. Paige, Trueman and Tadron realized that left-handed protons should produce more W’s than right-handed protons. This work on W production and diject production was the predecessor of the jet studies for supersymmetric theories described by Paige.
During Trueman’s time as associate laboratory director (reviewed by Samios), the high energy program at BNL performed a number of classic experiments, including the g-2 experiment (reviewed by Roberts) and the K→πνν experiment (reviewed by Bryman). This was also the beginning of the development of the RHIC experimental programs and the era of the light ion program at BNL.
The symposium also heard from Leo Stodolsky about advances in understanding dark matter.
Sam Aronson began the day by thanking Larry for his service to the laboratory and wishing him the best for his retirement—a sentiment echoed by all at the Truemanfest.
The Relativistic Heavy Ion Collider at Brookhaven National
Laboratory is a world-class scientific research facility primarily
funded by the U.S. Department of Energy Office of Science. Hundreds
of physicists from around the world use RHIC to study what the
universe may have looked like in the first few moments after its
creation. What physicists learn from these collisions may help us
understand more about why the physical world works the way it does,
from the smallest subatomic particles, to the largest stars.