From my archive, on Peter Higgs and his boson.
I interviewed Higgs, who has just won the Nobel Prize for his prediction of the subatomic particle known as the Higgs boson, only briefly. It was during a coffee-break conversation after a talk he gave in Ann Arbor, Mich., in 2001. And I took his picture.
In his talk, describing the events that led to the prediction of his boson, he provided an enlightening case study about how science really works. As with so many good ideas in science, Higgs had trouble getting his paper published.
It was the summer of 1964. Physicists were in the midst of trying to understand how nature’s particles and forces fit together. A few months earlier, Murray Gell-Mann had published a paper proposing strange new particles called quarks in the journal Physics Letters. His idea stemmed from mathematical symmetries that seemed so useful for describing particle properties.
Symmetries ensure that changes in point of view don’t mess up the underlying physics. You can rotate a snowflake by 60 degrees but it still looks just the same; the laws of physics stay the same whether you’re flying through space or sitting in a chair. But symmetries in equations still allow asymmetries in real life. Particles don’t all have the same masses, for instance, and forces don’t all have the same strength. Somehow the symmetry in the equations describing particles and forces gets “broken.” Some particles have mass because something breaks the perfect symmetry of all particles being massless.
Today, everybody who follows a physicist on Twitter knows that the Higgs field, an odorless, tasteless force that is always with us, permeating all of space, is involved in the symmetry breaking that gives particles mass. Higgs and several other physicists proposed the basic idea in 1964. But Higgs was the first to specifically suggest that the field would betray its presence by the existence of a particle from the boson family. It was all thanks to young misguided physicist and a hard-to-please editor.
On July 16, 1964, Higgs read a paper by a physicist named Walter Gilbert concerning recent advances in the math describing superconductivity (in which symmetry breaking was a key idea). Some particle physicists believed that the superconductivity math might be useful in evading the Goldstone theorem. (You don’t need to know what it is, just that it was a problem.)
Gilbert contended that you couldn’t get around the Goldstone theorem by using the superconductivity method. Higgs was not convinced.
“My response after reading Gilbert’s paper was, ‘Oh yes you could,’“ Higgs said in his 2001 talk.
Eight days after reading Gilbert’s paper, Higgs sent a short paper of his own to Physics Letters, demonstrating that the Goldstone blockade could be evaded. That paper was accepted. Then Higgs worked out how a field in space could break symmetry and provide subatomic particles with mass. On July 31 he sent that paper to Physics Letters. This time, the editor rejected it.
Higgs was annoyed, but on reflection realized that he should have figured out some way in which his paper would have been “experimentally interesting.”
So he revised the paper, adding that “it is worth noting that an essential feature” of his theory was “the prediction of incomplete multiplets of scalar and vector bosons.” Translated from physics lingo into English, he was predicting new particles to be discovered. One was the scalar particle now known as the Higgs boson. (There might be more than one species, which is one of the reasons physicists at the Large Hadron Collider took so long to make sure they had discovered the right one.)
At the time, not everybody believed Higgs. “I got a letter from Walter Gilbert telling me why I was wrong,” Higgs said. But before long Higgs’ idea caught on, and Gilbert switched from physics to biology. That was obviously a good move, because Gilbert won the Nobel Prize in chemistry in 1980.
When he finished the revised version of his paper, complete with the new particle prediction, Higgs sent it off for publication — but not to Physics Letters. He was irked by the initial rejection so he sent the new version to Physical Review Letters, where it was published on October 19, 1964.
In retrospect, Higgs owed the Physics Letters editor some gratitude. It was the rejection, after all, that led to the prediction of the new boson.
“Otherwise,” Higgs told me, “I might never have mentioned it.”