$6 billion particle accelerator

 
Particle Physicists Plan the Next Big Thing

By JAMES GLANZ

SNOWMASS VILLAGE, Colo., July 7 — The directors of major
physics laboratories in Europe, the United States and Japan
gathered at this mountain resort this week to make plans for a new
particle accelerator they all agreed would be so large, powerful and
expensive that it could be built only if they all cooperated on a scale
without parallel in scientific history.

The machine could cost more than $6 billion, would measure roughly 20
miles from one side to the other and would require so many advanced
technologies that no single country could supply them all. Its goal would be
to mine the areas opened up by evidence indicating that ultrapowerful
new accelerators may be crucial in explaining not just the nature of matter
and energy but also the birth of the universe and the structure of space
and time themselves.

According to some theories, the machine could see evidence for
previously unknown dimensions, beyond the usual four, lurking right under
humanity's noses. Elusive particles that account for most of the mass of
the entire universe — the so-called dark matter — could also turn up.

Scientists also hope to test theories that describe how the universe may
have behaved in its first explosive instants and to work out the detailed
properties of a particle called the Higgs boson. Believed to be the key to
why other particles have mass, the Higgs, if it exists, may be discovered
by accelerators now operating or being built.

The lab directors, here with more than a thousand other scientists for a
three-week conference on the future of particle physics, agreed easily on
the science at stake. But they were divided over more mundane but
equally complex issues, like the design of the accelerator, where it would
be built and who would supply the extraordinary amount of money needed
to pay for it.

The technical debate involves questions like whether the particles should
be accelerated in a straight line or on a circular racetrack, whether
electrons or their much heavier cousins, protons, should be smashed
together and just what technologies should be used to push the particles
to the tremendous energies that would be necessary.

The laboratory directors, who tend to favor a linear collider involving
electrons but are still divided on the best technical approach, argued that
the transformation of particle accelerators from mere probes of matter to
cosmic discovery machines justified the expense of a gigantic new
device, assuming that nations agree to pool their resources. "It is forced
on us by the richness of our science and the cost of our science," said Dr.
Jonathan Dorfan, the director of the Stanford Linear Accelerator Center,
or SLAC, in California. Nations can no longer afford to duplicate one
another's efforts, he said.

One thing that apparently will not change is the lengthy lead time needed
for big particle physics experiments. The most powerful machine now
operating is the newly upgraded Tevatron accelerator at the Fermi
National Accelerator Laboratory near Chicago. It will be several years
before the Tevatron collects enough data to have meaningful results.

Then, by 2006, the much more powerful Large Hadron Collider, or L.H.C.,
is scheduled to be finished in Geneva at CERN, the leading European
particle physics laboratory. The two machines use protons for collisions
— one reason the directors are behind an electron collider, which they
say would provide crucial complementary information.

The new machine, which would be by far the most powerful such collider
ever built, could not be ready to collect data until 2011 or 2012 at the
earliest, assuming that construction could begin by 2004 or 2005.

Unlike the Large Hadron Collider, which CERN designed before inviting
the participation of Japan and the United States, the new approach is to
include all participants at every stage. The United States is contributing
$531 million to the $4 billion hadron collider.

"I think what we're looking at is a way for the international
high-energy-physics community to come together and develop its own
plan," said Dr. S. Peter Rosen, associate director for high-energy and
nuclear physics at the Energy Department's Office of Science. That will
require new ways to carry on global collaborations so the host country
does not benefit at the expense of the other participants, said Dr. Albrecht
Wagner, director of DESY (pronounced "daisy"), a particle physics
laboratory in Hamburg, Germany.

Dr. Wagner has proposed building a kind of accelerator that can be
operated almost entirely remotely — from control rooms at Fermilab or
the KEK accelerator laboratory in Japan, say, if the machine was in
Germany. A team led by DESY has already come up with a detailed
design for a linear collider.

In Dr. Wagner's plan, elements of whatever machine is constructed would
be built at scattered sites around the world before being assembled in
one spot, a strategy designed partly to avoid favoring the host country's
manufacturers.

Several factors have already impinged on those rather utopian
perspectives. For one thing, the backing of the United States, as the
historical leader in high-energy physics and the world's leading economy,
would be a central requirement for any successful plan. Lack of United
States support "will kill the project," Dr. Wagner said.

As it happens, both of the top scientific players in the United States — Dr.
Dorfan and Dr. Michael S. Witherell, director of Fermilab — strongly favor
building the machine on American soil and, in fact, somewhere near their
own laboratories.

Despite their own calls for the globalization of the machine, Dr. Dorfan
and Dr. Witherell believe that the particle physics community in the United
States may atrophy without a new front-line device to look forward to.
They also fear that the highly specialized cadre of engineers and
physicists who design and build new accelerators, not only for high-
energy physics but also for medical and industrial uses, may leave the
country to work at the new machine if it ends up abroad.

With the Large Hadron Collider now under construction in Europe, Dr.
Dorfan said, "I think it's our turn to be the host to the next major facility."

But the American approach is already creating stark disagreements even
by the standards of particle physics, a field not known for social niceties.
This week, for example, Dr. Hirotaka Sugawara, the director of KEK,
denounced Fermilab's bid to be the site for the project.

Dr. Sugawara said the collider should be built in Japan, near SLAC in
California or some other place in the Pacific Rim — which he defined, in
so many words, as a region from which the Pacific Ocean can be seen.

"And people in the state of Illinois cannot do that," he said pointedly as Dr.
Witherell sat in the front row.

Dr. Witherell, looking stunned, went to the podium to respond.

"If we were dealing with something that cost a billion dollars, of course we
wouldn't be in this situation," Dr. Witherell said, referring to how the
multibillion-dollar price tag is forcing the collaboration. "I think for many
reasons it would be right to build the machine; it would be right to build it
at Fermilab."

But in an interview, Dr. Sugawara raised the darkest specter in the recent
history of particle physics in the United States: the death of the
Superconducting Supercollider. He pointed out that after the United
States got financing from other countries for the collider, a large
accelerator that would have been built in Waxahachie, Tex., Congress
killed the project in 1993 amid delays and cost overruns.

"There was damage to U.S.-Japan relationship," Dr. Sugawara said,
explaining that large amounts of political capital had been spent in Japan
to get the country involved. "Not just among scientific officials but also
government officials," he said.

In reply, Dr. Witherell said in an interview that the Superconducting
Supercollider was now being used as a model of how not to conduct a
scientific collaboration. For example, he said, seeking international
partners so late in the game was incorrect, as was placing the collider far
from any existing lab that could take responsibility for it.

One reason he is offering Fermilab as a site, Dr. Witherell said, is that the
underground tunnel for the accelerator could be built very close to the lab
or — unlike the SLAC proposals — even pass through its grounds.

Compared with the political complexities, the scientific and technical ones
may seem positively simple.

Assuming that some agreement is reached and the financing for a linear
machine is forthcoming, scientists will still have to choose between the
German design, dubbed Tesla — which features superconducting
materials in the cavities that accelerate particles — and the Next Linear
Collider, a more conventional design.

Several physicists at the meeting said Tesla could probably produce
more intense particle beams, leading to a higher rate of collisions, while
the Next Linear Collider could ultimately reach higher energies.

"It comes down to which one do you think is more important," said Dr.
David Burke, a SLAC physicist who is project director of the Next Linear
Collider, which he favors.

Even if that question can be ironed out, some physicists favor quickly
leaping ahead to a Very Large Hadron Collider, involving ultrapowerful
collisions between protons, rather than building an electron machine in
this country at all. A proponent of the Very Large Hadron Collider, Dr.
Peter Limon, head of the technical division at Fermilab, described the
machine at a plenary session here.

The two kinds of machines work quite differently because electrons are
pointlike particles while protons are bundles of more fundamental
particles called quarks and gluons. Although the energies of the two
machines are not directly comparable, proton colliders are seen as brute-
force probes of the energy frontier; electron colliders are often more
suited for precision measurements.

Because the host country would be expected to pay 50 to 60 percent of
the cost of any machine, some physicists oppose building a linear collider
in the United States because its financial demands would squelch other
interesting projects for decades.

"I have a hard time believing there would be money for anything else,"
said Dr. Andrew Sessler, a physicist at Lawrence Berkeley National
Laboratory and a proponent of a new project to study the nearly massless
particles called neutrinos.

For all those skirmishes, though, some scientists said the maneuvering,
including Dr. Sugawara's statements, should be seen mostly as the
opening moves in a field in which long-term strategies have — by
necessity — become an art form.

"The lab directors are thinking ahead to the end game," said a particle
physicist at the meeting. "I think Sugawara moved his queen out last
night."
 

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