Genius: The Life and Science of Richard Feynman

by James Gleick

Gell-Mann and, independently, an Israeli theorist, Yuval Ne’eman, found a way in 1961 to organize the various symmetries of spins and strangeness into a single scheme. It was a group, in the mathematicians’ sense of the word, known as SU(3), though Gell-Mann quickly and puckishly dubbed it the Eightfold Way. It was like an intricate translucent object which, when held to the light, would reveal families of eight or ten or possibly twenty-seven particles—and they would be different, though overlapping, families, depending on which way one chose to view it. The Eightfold Way was a new periodic table—the previous century’s triumph in classifying and thus exposing the hidden regularities in a similar number of disparate “elements.” But it was also a more dynamic object. The operations of group theory were like special shuffles of a deck of cards or the twists of a Rubik’s cube. Much of SU(3)’s power came from the way it embodied a concept increasingly central to the high-energy theorist’s way of working: the concept of inexact symmetry, almost symmetry, near symmetry, or—the term that won out—broken symmetry. The particle world was full of near misses in its symmetries, a dangerous problem, since it seemed to permit an ad hoc escape route whenever an expected relationship failed to match. Broken symmetry implied a process, a change in status. A symmetry in water is broken when it freezes, for now the system does not look the same from every direction. A magnet embodies symmetr...