BY FRANK A. WILCZEK
School of Natural Sciences
Institute for Advanced Study
" Although the standard model of particle physics largely crystallized in the mid-1970s and has been verified by numerous experiments, some of the conceptually clearest and most decisive experiments have been difficult to perform for various technical reasons. It is a pleasure to note that two such experiments have been done recently that mark milestones in our understanding of the microworld. One directly confirms the existence of couplings among color gluons, with the required form and magnitude.
I.H. Park, S. Schnetzer, J. Green, S. Sakamoto, et al, “Experimental evidence for the non-Abelian nature of QCD from a study of multijet events produced in e+ e- annihilations,” Physical Review Letters, 62, 1713-6, 10 April 1989. (The AMY Collaboration, representing 20 institutions worldwide)
The second reports measurement of the most fundamental interaction process between electrons...