space@mit-mc (03/21/85)
From: Hans.Moravec@cmu-ri-rover.arpa
n130 2330 20 Mar 85
BC-PARTICLES
By WALTER SULLIVAN
c.1985 N.Y. Times News Service
NEW YORK - Astrophysicists say they believe a cosmic power source
far out in space may be bombarding the earth with subatomic particles
different from any known to science.
Recordings taken deep in a mine at Soudan, Minn., an Ohio salt mine
and beneath a World War II bunker at the University of Kiel in West
Germany are believed to include scores of high-energy particles from
the general direction of Cygnus X-3, a double-star system in the
constellation Cygnus.
Scientists said Wednesday that they were at a loss to explain the
new data in terms of known forms of radiation, and stressed that the
recordings needed much more analysis.
But they said the data called into question the suggestion made
several weeks ago, on the basis of particles detected in a salt mine
beneath Lake Erie, that Cygnus X-3 may be a major source of extremely
high energy neutrinos.
Neutrinos are the most penetrating and elusive of all known
subatomic particles. They can pass through the earth or almost any
amount of detecting material without producing any effect.
In recent days, reports of the Minnesota and Ohio observations have
prompted underground observatories elsewhere to seek verification,
including those in the Frejus and Mont Blanc tunnels that link France
and Italy under the Alps.
Dr. Donald Cundy of CERN, the European Organization for Nuclear
Research in Geneva, Switzerland, said Wednesday that his recordings
under Mont Blanc had shown ''something interesting,'' but he was not
prepared to say more.
One member of the Ohio salt mine team, Dr. John Learned of the
University of Hawaii, who has analyzed the observations there, says
he is ''pretty well convinced'' that some new form of physics is
involved in the observed particles.
But Dr. Shelton Glashow of Harvard University, winner of a Nobel
Prize for his theoretical contributions to high-energy physics,
described the reports as ''unconvincing evidence for an unbelievable
result.'' In a telephone interview, he termed the findings ''really
wild,'' but said their validity ''is, of course, possible.''
The bunker observations in West Germany were actually reported
several years ago, but until now were widely regarded as an
experimental error.
Cygnus X-3 was originally identified as a source of powerful X-rays.
It is now believed to be two extremely dense stars circling one
another at close range and, in some unknown manner, emitting profuse,
high-energy radiation in tempo with the motion of the two objects
around one another every 4.8 hours.
In analyzing the salt mine data for evidence of neutrinos from
Cygnus X-3, scientists assumed those that had passed through
thousands of miles of rock would be most easily distinguished from
other forms of radiation. The search, therefore, focused on particle
tracks originating when Cygnus X-3 was below the horizon or very low
in the sky. About 20 candidate events fit the direction and 4.8-hour
period of that source.
On learning of the salt mine results, the Minnesota group began
examining their data, but included arrivals from directly overhead.
They found that candidate particles arrived readily when Cygnus was
high in the sky but not when it was below the horizon. This indicated
that, unlike neutrinos, the particles can traverse only a limited
amount of rock. Further, far too many particles were recorded for
them to have the elusive character of the ghostly neutrinos.
In any case, the particles detected are assumed to be muons - heavy,
short-lived counterparts of electrons - produced by high-energy
particles hitting material in the detectors or nearby walls. Attempts
to identify sources of cosmic rays, which are extremely high-energy
particles that rain on the earth, are conducted deep under ground to
avoid less energetic forms of radiation. Even so, the detectors still
record large numbers of muons generated by less powerful cosmic rays
hitting the atmosphere.
Thus, according to Dr. Marvin L. Marshak of the University of
Minnesota, his group's underground evidence of Cygnus X-3 bombardment
has been extracted from 870,000 recorded muon penetrations.
The first step was to set aside all but those arriving from within 3
degrees of the direction of that hypothetical source. This reduced
the sample to 1,100 penetrations, or events. The second step was to
analyze their arrival times to see if a significant number fit into
the 4.8-hour cycle of known emissions from Cygnus X-3.
Surface observatories in the United States, Britain and Germany have
shown that Cygnus X-3's output of other radiation, such as extremely
high-energy gamma rays, shows such a periodicity. Analysis of
recordings in the Soudan mine by a collaboration of the University of
Minnesota and Argonne National Laboratory has attributed 80 events to
Cygnus X-3, with an error margin of 20.
Marshak and his colleagues reported their data, in tentative form,
to Physical Review Letters. However, collaborators in the salt mine
observations, including physicists from the University of California
at Irvine, the University of Michigan and Brookhaven National
Laboratory, have not done so as they sought to strengthen their
analysis.
nyt-03-21-85 0229est
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