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200GeV Collisions at RHIC

Posted by michael on from the no-blackholes-yet dept.

PHENIX Experiment writes: "Brookhaven Labs has produced for the first time, collisions of gold nuclei at a center of mass energy of 200GeV/nucleon. This is a new energy regime for the high energy nuclear physics relativistic heavy ion program which is now getting underway. We have put together a bunch of nice photos of event displays for some nice central collisions, the collisions where the two nuclei hit head on. Over the next 6 months or so, we are looking to collect on the order of a petabyte of data which will then be analyzed using our VA Linux farm operated by the RHIC Computing Facility."

6 of 47 comments (clear)

  1. Re:Wow. 200GeV by deglr6328 · · Score: 3

    Fermilab already has a Tevatron.

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    - "Hear that?! The percolations are imminent! Cease your ingress!"
  2. Quark/Gluon plasma by fnordboy · · Score: 4

    One of the main reasons that RHIC was developed was to study the quark-gluon plasma. Though there are more energetic acclerators (Fermilab's Tevatron, for example), RHIC is unique because it collides gold nuclei together instead of single atoms or leptons. Even so, most of a gold nucleus is empty space, so when they collide, the nuclei basically pass through each other, but at such a high energy that the bonds that hold the quarks together are temporarily broken, creating a very hot, dense quark-gluon plasma. (BTW, gluons are the carriers of the 'strong' force and hold quarks together to make hadrons such as protons and neutrons). This allows physicists to study the properties of very hot, dense matter, such as the stuff that existed shortly after the big bang, before the era where protons and neutrons were formed. A paper describing the potential physics of it can be found here.

  3. The Hardware by daniel_isaacs · · Score: 3
    Since few of us are knowledgable enough about the details concerning the scientific expeiriment, I thought I'd point out the part of the story most of us can dig. The hardware. Managing a petabyte of data is a Herculean effort. These guys have a nice setup.

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    - Dan I.
  4. Not quite like pool, but nice english by Kibo · · Score: 3
    IIRC this device was constructed primaily to provide insight into the quark gluon plasma that may have existed/did exist in the early universe.

    The gold ions don't collide as such and shatter. IANAHEPPOAFYOLE (I am not a high energy plasma physicist or 15 year old leagal expert), but because they're traveling at relativistic speeds they pancake and pass through each other inelastically imparting some of their lost energy to the vacuum behind them. The vacuum, being unstable with this extra energy spots forth a soup of primordial particles. Particles, who's composition depends on its temperature, which in turn comes from the enegry imparted to the vacuum in the collision. One interesting particle to look at is J-psi. They could simply graph detections of J-psi artifacts vs temperature or energy density (variable the researchers control). It should look just like any phase transition diagram, such as one might do for ice to water. At a certain critical temperature J-psi should essentially 'melt' and then we would know our quark gluon soup is done. And if my hamerster is right, that should be at about 2 trillion degrees K. Careful, the soup's hot.

    In a way, what is being done is looking, in extreamly fine detail, at what came before the cosmic background by something like 300,000 thousand years when our universe was about the size of the solar system.

    I think someone published a paper that a device like this might impart enough energy to the local vacuum, that it might settle back down to a lower energy state and trigger a big bang giving birth to a new universe. (Now that would be the weapon of an evil genious worthy of James Bond.) Supposedly something like 5,000 similar lead - lead collisions take place every year in the universe, so it's probably pretty unlikely. But it would be pretty funny if they had to state man wouldn't destroy the universe from Long Island for the EPA. Of course it'd probably be even funnier if they were wrong.

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    --Jimmy has fancy plans; and pants to match.
  5. You've got to love the dry humor.... by Kibo · · Score: 3
    The total number of collisions that will occur in RHIC over ten years turns out to be far fewer than the number of potentially 'dangerous' iron-iron collisions that occur on the surface of the moon in a single day. For every production of a dangerous strangelet at RHIC, one expects one hundred thousand trillion to have been produced on the moon during its lifetime, any one of which would have converted the moon explosively to strange matter a phenomenon that is known not to have occurred.

    Don't you get the impression they resented having to write this?

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    --Jimmy has fancy plans; and pants to match.
  6. Large detective work ahead by Yazeran · · Score: 3
    It's going to be interesting to see if they can sort out all those sub-atomic particles created by a gold-gold collision. Remember that we are talking of a colision involving approx 500 nucelons (portons and neutrons) here. I'm amazed that they use such heavy atoms, as so many particles are involved. I would guess that if they were looking after the Higgs particle, they would have one hell of a detective work ahead of them.

    But then again, they have those Linux'es to handle that, so i guess they'll manage. One doesn't start something like this unless you are quite sure you'll learn something.

    Yours Yazeran

    Plan: To go to Mars one day with a hammer.