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<DIV style="MARGIN-LEFT: 1em; MARGIN-RIGHT: 1em" align=left><A
href="http://www.latimes.com/news/science/la-sci-matter19apr19,1,6756098.story">http://www.latimes.com/news/science/la-sci-matter19apr19,1,6756098.story</A><BR>
<H4>THE NATION</H4>
<H1>Atom Smasher Yields 'Perfect Fluid'</H1>
<H2>The unexpected finding could provide insight into the creation of the
universe, scientists say.</H2>By Thomas H. Maugh II<BR>Times Staff
Writer<BR><BR>April 19, 2005<BR><BR>Researchers smashing gold atoms together to
mimic conditions in the first microseconds after the creation of the universe
have observed an unexpected new state of matter.<BR><BR>Instead of the thin,
fiery gas of quarks and gluons that they expected, they found instead a dense
drop of the elementary particles that behaves like a hitherto unseen "perfect
fluid."<BR><BR>It is "a truly stunning finding," said Raymond L. Orbach,
director of the Department of Energy's Office of Science.<BR><BR>Quarks are the
fundamental building blocks of protons, neutrons and other subatomic particles,
held together in pairs and triplets by mysterious particles called gluons, whose
attractive force is so overwhelming that neither quarks nor gluons have ever
been seen separated from one another in nature. <BR><BR>When the universe was
created, however, it consisted only of a massive swarm of gluons and quarks, a
so-called quark-gluon plasma, which quickly condensed into conventional matter.
<BR><BR>Four separate international teams now believe that they have created a
small, short-lived quark-gluon plasma whose behavior will provide insights into
the moments after the big bang that started everything off.<BR><BR>"We think we
are looking at a phenomenon [similar to what happened] in the universe 13
billion years ago when free quarks and gluons … cooled down to the particles
that we know today," said Sam Aronson of Brookhaven National Laboratory in
Upton, N.Y., where the experiments were performed.<BR><BR>Aronson spoke Monday
at a news conference at a meeting of the American Physical Society in Florida,
where the results were presented.<BR><BR>"The matter that they are seeing is
even more interesting … than we thought it would be," said theoretical physicist
Berndt Mueller of Duke University. "They have presented a compelling case for
the achievement of an important milestone in the quest for the quark-gluon
plasma," a quest that has been underway since the development of modern nuclear
physics.<BR><BR>The finding was so unexpected that the teams spent more than two
years confirming their results. Their conclusion will be published in four
papers in the journal Nuclear Physics A.<BR><BR>During the 1990s, researchers
experimented by smashing hydrogen atoms and other small particles together at
speeds approaching that of light — so-called relativistic velocities. But those
collisions were too small to produce the energies necessary to form a
quark-gluon plasma.<BR><BR>In 1999, Brookhaven finished construction of the
Relativistic Heavy Ion Collider, which allowed collisions between atoms as large
as those of gold at the highest energies ever achieved in man-made particle
accelerators. Experimental runs began the next summer, and researchers have now
compiled data from hundreds of millions of collisions, each producing thousands
of particles.<BR><BR>Because the collisions produce temperatures 150,000 times
that of the core of the sun, theoretical physicists including Mueller predicted
that the quark-gluon plasma would be a gas in which individual components would
streak in every direction in an uncoordinated fashion.<BR><BR>What the teams
found instead was that the particles in the plasma formed a liquid in which the
individual components moved in a coordinated fashion, much like a school of fish
in the ocean. "The data indicate that it is the most perfect fluid we have ever
seen," Mueller said.<BR><BR>A perfect fluid is a theoretical ideal, a
low-viscosity, frictionless liquid whose behavior is described precisely by the
equations of fluid mechanics. Honey is the exact opposite of a perfect fluid,
gooey and viscous, resistant to any motion through it. <BR><BR>"Creating a
perfect fluid means the viscosity is very, very low," Mueller said. "If you
could drag a spoon through it, it would have almost no resistance."
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