[Paleopsych] NYT: At One Trillion Degrees, Even Gold Turns Into the Sloshiest Liquid
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Tue Apr 19 13:56:56 UTC 2005
At One Trillion Degrees, Even Gold Turns Into the Sloshiest Liquid
[CHE writeup appended.]
By KENNETH CHANG
It is about a trillion degrees hot and flows like water.
Actually, it flows much better than water.
Scientists at the Brookhaven National Laboratory on Long Island
announced yesterday that experiments at its Relativistic Heavy Ion
Collider - RHIC, for short, and pronounced "rick" - had produced a
state of matter that is unexpectedly sloshy.
"Every substance known to mankind before would evaporate and become a
gas at two million, three million degrees," said Dr. Dmitri Kharzeev,
a theoretical physicist at Brookhaven. "So the big surprise here is
the matter created at RHIC is a liquid."
It even approaches the best of all possible liquids, with almost no
viscosity. "It's more fluid than the water in this glass," Dr.
Kharzeev said, referring to a glass of water in front of him at a news
conference at a meeting of the American Physical Society in Tampa,
Four scientific papers totaling hundreds of pages and analyzing three
years of data from the RHIC have been accepted for publication in the
journal Nuclear Physics A.
But as they have for the last couple of years, the scientists stopped
short of announcing that they had created a subatomic soup known as
quark-gluon plasma, the impetus for building the $600 million
Physicists are interested in quark-gluon plasma because it will help
them understand the "strong force" that holds protons and neutrons
together, and the RHIC experiment also recreates the state of matter
that filled the universe for up to the first ten-thousandth of a
second after the Big Bang.
The mathematics that describe the strong force are notoriously hard to
solve. One reason theorists had focused on the quark-gluon plasma's
being a gas was that idea simplified the equations to ones they could
Trying to understand the more fluid state, some theorists have
reported progress using mathematical tools from string theory, while
others have pulled in cosmology and black holes. "You look for
analogies where the mathematics is tractable," Dr. Berndt Mueller, a
professor of physics at Duke University, said in an interview.
The RHIC accelerates gold nuclei - atoms without their usual shroud of
electrons -to 99.995 percent of the speed of light around two
2.4-mile-wide rings and smashes them together.
Physicists expect that in the fireballs of these violent collisions,
protons and neutrons in the nuclei melt into smaller pieces known as
quarks and gluons. In ordinary everyday matter, quarks are too tightly
bound together by the gluon particles to pull out a single quark for
In 2000, scientists at the CERN particle physics laboratory in
Switzerland claimed to have created a quark-gluon plasma, but many
criticized that announcement as premature. The RHIC scientists say
they want all of their experimental data in place before putting in
their official announcement. The expectation, though, is that they
have been making quark-gluon plasma ever since the collider began
running in 2000.
"Circumstantially, this is a liquid of quarks and gluons," said Dr.
Samuel Aronson, the laboratory's associate director for high energy
and nuclear physics. "Circumstantially, that is what fits the data."
At the news conference yesterday, participants danced around what to
call what they had made and focused instead on its surprising
When two gold nuclei collide head on, the protons and neutrons
dissolve into a tiny droplet. It lasts a fraction of a second before
condensing into a shower of ordinary matter particles that fly
outward. Protons and neutrons consist of the two most common types of
quarks, up and down, but the immense energy of the collisions also
produces heavier quarks known as charm, strange and bottom.
The pattern of particles recorded by the four detectors at the RHIC
tells physicists that the conditions that existed in the droplet were
In the last two years, additional experimental runs at the laboratory
have looked at collisions of copper nuclei to "make sure what we think
we now understand about this liquid is true," said Dr. Timothy J.
Hallman, the spokesman for one of the four detectors.
The most recent runs have also been testing the prediction that a
reduced amount of charmonium - a particle that consists of a charm
quark paired with an anticharm antiquark - would be emitted in the
presence of a quark-gluon plasma.
A definitive quark-gluon plasma announcement could be made this year.
But the pace of future discoveries may slow. Proposed budget cuts at
Brookhaven would cut the time for the collider experiments, from 30
weeks this year to 12 weeks next year. Brookhaven would also have to
lay off some of its staff.
"It means," Dr. Aronson said, "that physics will come out, I would
say, something like half speed."
The Chronicle: Daily news: 04/19/2005 -- 02
'Perfect Fluid' Emerges in High-Energy Experiments That Mimic Big Bang
By RICHARD MONASTERSKY
Physicists announced on Monday that they had created a new state of
matter, an almost perfect liquid that mimics the hellish conditions
just after the Big Bang.
At a meeting of the American Physical Society in Tampa, Fla., the
researchers announced the results of experiments at Brookhaven
National Laboratory, in New York, where physicists have been smashing
atoms together to create subatomic fireballs of one trillion degrees.
Their experimental facility, known as the Relativistic Heavy Ion
Collider, or RHIC, was built to explore a type of primordial matter
called a quark-gluon plasma.
Quarks and gluons are the building blocks of ordinary matter. In
today's world, they are normally locked up tight within protons,
neutrons, and other particles by the strong force, one of the four
fundamental forces in nature. But a fraction of a microsecond after
the Big Bang, the universe was so hot and dense that quarks and gluons
whizzed around freely.
Over the past five years, researchers at RHIC have been accumulating
evidence that when gold nuclei collide at close to the speed of light,
they temporarily create a new state of matter with free quarks and
gluons, if only for 10^-23 seconds. The brevity and small size of the
collisions ensure that the experiment does not pose a risk to public
safety, laboratory officials said. Some of the scientists say that the
state of matter is the long-sought quark-gluon plasma, while others
have been reluctant to use that term until more evidence comes in.
This week, however, the researchers announced that the material
created by the collisions is a fluid, not the expected gas. And that
fluid has unusual properties.
"The state of matter we created behaves like a very-low-viscosity,
perfect fluid," said Samuel H. Aronson, the associate lab director at
Brookhaven who oversees RHIC. It is the closest thing to a perfect
fluid ever observed, he said.
Evidence from particles that fly out of the collision zone suggests
that the quarks and gluons flow together in a coordinated way, with
very little friction between particles. Normal fluids have some
viscosity, some sticking friction that absorbs energy and impedes its
flow. But the material created at RHIC -- whether it is a quark-gluon
plasma or some other quark-gluon matter -- comes extremely close to
behaving like a fluid without any viscosity, said the researchers, who
will publish their results in a future issue of Nuclear Physics A.
Peter Braun-Munzinger, a professor of physics at the Darmstadt
University of Technology, in Germany, and one of the directors of the
GSI heavy-ion-research laboratory, also in Darmstadt, called the new
results surprising. "The apparent viscosity is so low that it behaves
almost like an ideal fluid," he said.
The results thus far are strong indications, he said, "but this is
still theoretical speculations." The hypothesis about a nearly perfect
fluid will be the center of the debate at a conference on quark matter
in Budapest in August, he said.
Background articles from The Chronicle:
* Smashing Gold (3/12/2004)
* Crazy for Quarks (4/26/2002)
45. mailto:rich.monastersky at chronicle.com
E-mail me if you have problems getting the referenced articles.
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