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By Root 2167 0

the problem; then he wanted to solve it his own way. Almost alone among physicists, he refused to referee papers for journals. He could not bear to rework a problem from start to finish along someone else’s track. (He also knew that when he broke his own rule he could be devastatingly cruel. He summarized one text by writing, “Mr. Beard is very courageous when he gives freely so many references to other books, because if a student ever did look at another book, I am sure he would not return again to continue reading Beard,” and then urged the editor to keep his review confidential—“for Mr. Beard and I are good personal friends.”) His persistently iconoclastic approach to other people’s work offended even theorists whom he meant to compliment. He would admire what they considered a peripheral finding, or insist on what struck them as a cockeyed or baroque alternative viewpoint. Some theorists strived to collaborate with colleagues and to set a tone and an agenda for whole groups. Gell-Mann was one. Feynman seemed to lack that ambition—though a generation of physicists now breathed Feynman diagrams. Still, he was frustrated.

He sometimes confided in his sister, Joan, who had begun a career in science herself, getting a doctorate in solid-state physics at Syracuse University. She was still living in Syracuse, and Feynman visited her when he went to Rochester. He complained to her that he could not work. She reminded him of all the recent ideas that he had shared with her and then refused to pursue long enough to write a paper. You’ve done it again and again, she said. You told me that Block might be right. And you don’t do a damn thing about it. You should write it up, for crying out loud, when you have something like this. She also reminded him that he had mentioned an idea for a universal theory of weak interactions—tying together beta decay and the strange-particle decays based on the weak force—and urged him, finally, to see where it would lead.

In its classic form, beta decay turns a neutron into a proton, throwing off an electron and another particle, a neutrino—massless, chargeless, and hard to detect. Charge is conserved: the neutron has none; the proton carries + 1 and the electron – 1. Analogously, in the meson family, a pion could decay into a muon (like a heavy electron) and a neutrino. A good theory would predict the rates of decay in such processes, as well as the energies of the outgoing particles. There were complications. The spins of the particles had to be reconciled, and for the massless neutrinos, especially, problems of handedness arose in calculating the appropriate spins. So the new understanding of parity violation immediately changed the weak-interaction landscape—for Feynman, for Gell-Mann, and for others.

In sorting the various kinds of particle interactions, theorists had created a classification scheme with five distinct transformations of one wave function into another. In one sense it was a classification of the characteristic algebraic techniques; in another, it was a classification of the types of virtual particles that arose in the interactions, according to their possible spins and parities. As shorthand, physicists used the labels S, T, V, A, and P, for scalar, tensor, vector, axial vector, and pseudoscalar. The different kinds of weak interaction had evident similarities, but this classification scheme posed a problem. As Lee pointed out at the 1957 Rochester meeting, most experiments on beta decay had demonstrated S and T interactions, while the new parity-violation experiments tended to suggest that meson decay involved V and A. Under the circumstances, the same physical laws could hardly be at work.

In reading Lee and Yang’s preprint for the meeting—Joan had ordered him, for once, to sit down like a student and go through it step by step—Feynman saw an alternative way of formulating the violation of parity. Lee and Yang described a restriction on the spin of the neutrino. He liked the idea enough to mention it from the audience during five minutes cadged from another speaker. He