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Jens 'n' Frens |
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I just wrote this for someone, and thought I'd post it here, two days before the folks at CERN give a press conference announcing the latest findings in the search for the Higgs boson.The electroweak model is built on the idea of a broken symmetry: just as the equation x2=1 is symmetric under a change in sign of x but no solution of the equation is similarly invariant, the electroweak model is symmetric but symmetric solutions require very high energies, and the symmetry in any case is not observed in the real world. The symmetry, among other things, precludes electrons and quarks from having mass; the mass terms would violate the symmetry. The Higgs field (among other things) transforms in such a way that if you stick it into the mass term for an electron or a quark, it makes the term as a whole symmetric again; the Higgs transforms in a way that cancels out the transformation in the rest of the term. This is why you read about the Higgs field "giving mass" to these particles, which isn't really wrong by science journalism standards, but doesn't feel quite right to me, either.I would note that, with the sole exception of our inability to find the Higgs boson, the electroweak model has been fantastically successful for more than thirty years; I have a book from thirty years ago that includes the masses of some electroweak bosons that were discovered the year after the book was published, and the masses are exactly right. Physicists are thus confident that the electroweak model is a very good description of most low-energy particle behavior. It is, however, an even stronger empirical result that electrons are not massless, hence the desire by the physics community to reconcile the two sets of observations. |
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