- Quote: By discovering the compression field and the leaning field, and perhaps others, and by studying how these fields behave and how they interact, you could begin to learn a great deal about their medium—for instance, that it’s a three-dimensional solid.
- Endnote: You might even discover these obscure fields by accident. For instance, you might observe processes that seemingly cause energy to disappear. That energy must have gone somewhere, and some poking around might reveal that it has been carried off by waves in a previously unknown field. Neutrino fields were discovered in much this way.
A class of radioactive processes observed in the early part of the 20th century, called “beta decay”, take the following form: an initial nucleus is transformed into a second nucleus plus what we now call an “electron”.
A problem soon became clear clear: energy and momentum are not conserved among the observed particles. Here’s the issue.
Suppose the initial nucleus is stationary. Then, if the particles after the decay really were only the second nucleus and the electron, energy and momentum conservation would impliy that the electron would always be observed to have the same amount of total energy.
But one finds experimentally that this is not the case; the electron’s total energy varies, and is different every time the process is observed.
After careful study, though, a clue emerged: the electron’s energy is always less than would be predicted by energy and momentum conservation. This suggests that perhaps there is a third, unobserved particle in the beta decay process, an electrically neutral particle with a relatively small rest mass, that carries off some energy. This would then leave less energy for the electron than we’d otherwise expect, and would lead the electron’s energy to vary depending on the motion of the unobserved particle..
This is what Wolfgang Pauli proposed, rather haphazardly, in late 1930 — that in beta decay, a particle of very small rest mass and no electric charge was being emitted along with the electron. He considered the idea too speculative to publish.
But by 1934, Enrico Fermi had incorporated Pauli’s idea into a detailed theory of beta decay — one which worked well right away, and which turned out to be a correct explanation of the phenomenon. [Fermi gave Pauli’s proposed particle the name “neutrino”, to distinguish it from the “neutron” which was directly discovered in 1933.] For instance, in the simplest form of beta decay, a neutron decays to a proton plus an electron plus an anti-neutrino.
Neither Pauli nor Fermi won their Nobel prizes for their contributions to neutrino physics — but perhaps they ought to have done. Pauli’s prize was for the Pauli Exclusion Principle (see chapters 16 and 25), of no less importance. As for Fermi, he won his prize for something that turned out to be a mistake — a misinterpretation of a discovery he’d made! (Oops.) Ah well.
But it hardly matters. Fermi was responsible for an enormous variety of crucial advances in both experiment and theory, and his Nobel prize was richly deserved, even if, in detail, it was awarded for the wrong thing.
