Re: The neutrino has mass?!

Loren Haarsma (
Mon, 8 Jun 1998 13:39:42 -0400 (EDT)

Ah, science reporting in the popular press....
The Washington Post reporting of this story is (once again) full of
phrases such as "drastic revisions" and "devastating blow" and "holy
grail of physics."

Note another phrase tucked away in the text of the story:

> But the long-awaited observation, to be announced in Japan....

Many (probably most) physicists have been expecting an observation of
neutrino mass for some time.

When I took Quantum Field Theory ten years ago, I learned that there
were some rather straight-forward extensions of the "Standard Model"
which included neutrino mass. Already then, the solar physicists who
were particularly certain of their models told the rest of the physics
community to "expect" to find neutrino mass. There was another
experiment, a year or two ago, which reported a neutrino mass in a
measurement good enough to convince many (most?) physicists. It sounds
like the Japanese collaboration really nailed the mass measurement -- an
impressive experiment. Cosmologists and particle theorists have been
ready and waiting for this piece of data for some time.

John E. Rylander asked:

> What's the status now, within the community of physicists interested in
> foundational physics especially, of the many-universe interpretation of
> quantum mechanics? Is that picking up steam, despite it's apparent
> ontological bloat?

As far as I can tell, many-universe interpretation of quantum mechanics
is very much a "fringe" interpretation. (There was a good and fairly
accessible review of different interpretations of quantum mechanics in
the March and April 1998 issues of "Physics Today.") Of greater general
interest, perhaps, is inflationary cosmology which predicts the Big Bang
producing many different causally disconnected "universes" (each with,
perhaps, slightly different laws of physics). Inflation theory makes a
few predictions which non-inflationary cosmology does not make,
predictions which are matched by observations. That doesn't mean
inflation is necessarily right, but it does make it worth paying
attention to.

Loren Haarsma