PHYS: Neutrinos have mass

Max More (maxmore@primenet.com)
Sat, 06 Jun 1998 11:58:06 -0700


Neutrino finding could be key breakthrough in physics

Copyright 1998 Nando.net
Copyright 1998 Reuters News Service
NEW YORK (June 5, 1998 11:56 a.m. EDT http://www.nando.net) - Scientists said
Thursday they have evidence that tiny sub-atomic particles called neutrinos
have mass, a finding that could be key to establishing the Grand Unification
theory of physics.
Physicists said that if the finding is confirmed by future experiments, it
will
cause a revision of the so-called Standard Model that describes
interactions of
elementary particle physics. In the Standard Model, neutrinos have no mass.
"These new results could prove to be the key to finding the Holy Grail of
physics, the unified theory," said John Learned, University of Hawaii
Professor
of Physics and Astronomy and one of the authors of a paper on a neutrinos
experiment in Japan.
"Neutrinos cannot now be neglected in the bookkeeping of the mass of the
universe."
The unified theory of physics, also called the Grand Unification, is what
scientists would like to see: A combination of what is known as strong
interaction, weak interaction and electromagnetism theory in a single
framework.
Grand Unification is a step removed however from the great quest of 20th
century physics -- coming up with the so-called "theory of everything" in our
universe that would also describe gravitational force.
Known to physicists as the "Superstring theory" it would explain everything
from what it was like in the milliseconds immediately after the Big Bang to
what keeps people and objects rooted to Earth.
The latest finding, to be presented in a paper Friday at a conference of
physics and astrophysics in Takayama, Japan, caused excitement in the
international physicist community.
"It's a really incredibly exciting moment because of all of the particles we
know neutrinos are among the most mysterious," said Professor Chang Kee
Jung of
SUNY StonyBrook in New York, one of the universities that took part in the
experiment.
He said neutrinos are tiny particles that float around without much
interaction. About 500 billion neutrinos can pass by a person's fingertip
every
second.
Neutrinos were discovered four decades ago and have been the subject of
intense
experimental and theoretical research.
An experiment deep inside a Japanese mine has yielded results that are outside
the Standard Model theory of elementary particle physics, which describes the
fundamental constituents of matter and their interactions.
"So far the Standard Model works really well, we can explain just about
everything we see but we know there has got to be something more out there,"
said Dr. Evalyn Gates, a research scientist at the University of Chicago who
was not involved in the project.
"Knowing that neutrinos do have mass begins to direct some of these models. It
would be the first definite evidence of new physics and that's why everyone is
excited about this."
The paper presented Friday in Japan has been sent to the Physical Review
Letters, a physics journal. It describes results from the first two years of
data collected from a $100 million experiment called Super-Kamiokande.
The experiment uses a 12.5 million gallon stainless steel-lined tank of highly
purified water located about 3,300 feet underground in a Japanese mine. Faint
flashes of light given off by the neutrino interactions in the tank were
observed by 13,000 lights.
The collaboration involves the University of Tokyo's Institute for Cosmic Ray
Research and includes six U.S. universities and eight from Japan.
By Grant McCool