| Subject: Re: quark-gluon plasma |
Author:
Blobrana
|
[
Next Thread |
Previous Thread |
Next Message |
Previous Message
]
Date Posted: 00:15:00 04/19/05 Tue
In reply to:
Info
's message, "quark-gluon plasma" on 20:00:53 06/19/03 Thu
Scientists using the Relativistic Heavy Ion Collider - a giant atom smasher - have created a new state of matter and showed what the early universe looked like for a very, very brief time. <br>For a tiny fraction of a second after the "big bang" birth of the universe, all matter was in the form of a 'Perfect' liquid, called a quark-gluon plasma.
At temperatures 10,000 times hotter than those found inside the sun and with just a few thousand particles, the nuclear physicists saw quarks behaving like a perfect liquid, flowing together like a school of fish, without turbulence or random motion.
The unexpected results agree with what string theory calculates how quarks should move in a quark gluon plasma
>The scientists are not yet ready to claim a definite
>discovery of this ancient state of matter, however.
>They say that must await corroborating experiments,
>also under way at the RHIC.
>The latest RHIC findings come from experiments
>conducted from January through to March 2003, in which
>a beam of heavy gold nuclei collided head-on with a
>beam of deuterons - much smaller and lighter nuclei,
>each consisting of one proton plus one neutron.
>These deuteron-gold experiments, along with other
>experiments using two colliding beams of protons,
>serve as a basis for comparison with collisions of two
>gold beams at the RHIC.
>The gold-gold collisions, which bring nearly 400
>protons and neutrons into collision at once, are
>designed to recreate, for a fleeting instant, the
>extremely hot, dense conditions of the early Universe.
>When two gold nuclei collide head-on, the temperatures
>reached are more than 300 million times the surface
>temperature of the Sun. It is thought the individual
>protons and neutrons inside the merged gold nuclei
>"melt" to form a tiny sample of quark-gluon plasma.
>When this happens a pair of energetic quarks can be
>knocked loose from within a proton or neutron. Each of
>these loose quarks produces a stream of particles
>emerging in opposite directions from the site of the
>collision.
>In the deuteron-gold experiments, back-to-back jets
>were seen to emerge but, puzzlingly, in head-on
>collisions from the earlier gold-gold experiments, one
>of the two jets was missing.
>In addition, fewer highly energetic individual
>particles were seen coming from gold-gold than from
>deuteron-gold collisions.
>Scientists are intrigued by these distinctions, which
>clearly show that head-on gold-gold collisions are
>producing a nuclear environment quite different from
>that of deuteron-gold collisions.
>One possible explanation is that if a quark pair is
>produced near the surface of the quark-gluon plasma,
>the outward-bound quark is able to escape, while the
>inward-bound quark is absorbed.
>This phenomenon is called "jet quenching" and was
>predicted to occur in quark-gluon plasmas.
>If further work proves that a quark-gluon plasma has
>been made then scientists hope to learn more about the
>strong nuclear force - the force that holds quarks
>together in protons and neutrons.
[
Next Thread |
Previous Thread |
Next Message |
Previous Message
]
| |
Feedback: 