How Pentaquarks May Lead To the Discovery of New Fundamental Physics 65
StartsWithABang writes: Over 100 years ago, Rutherford's gold foil experiment discovered the atomic nucleus. At higher energies, we can split that nucleus apart into protons and neutrons, and at still higher ones, into individual quarks and gluons. But these quarks and gluons can combine in amazing ways: not just into mesons and baryons, but into exotic states like tetraquarks, pentaquarks and even glueballs. As the LHC brings these states from theory to reality, here's what we're poised to learn, and probe, by pushing the limits of quantum chromodynamics.
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Re:Anyone know why this moron does this? (Score:5, Funny)
Some researcher connected a cow's brain to the internet and gave it a Slashdot account.
Well, that would explain the editors...
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Some researcher connected a cow's brain to the internet and gave it a Slashdot account.
Well, that would explain the editors...
Bit harsh on cows though.
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Or maybe string cheese theory?
Mmmmm...string cheese...
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How does this relate to string theory ?
It doesn't.
This is real science.
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Re:A is for anthropocentric. (Score:1)
http://muppet.wikia.com/wiki/F... [wikia.com]
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Actually, you CAN'T do that (Score:5, Interesting)
At higher energies, we can split that nucleus apart into protons and neutrons, and at still higher ones, into individual quarks
In one sense that seems to be something you really can't do. The force between free quarks increases with distance to about 10,000N, then remains constant (no, I have no idea how this makes any sense, but it's what I read). Any force sufficient to tear two quarks apart is sufficient to generate new quarks which then bind with the "free" quarks. So you never see quarks by themselves.
IANAP, though. Does the above really mean that if you had two free quarks separated by a kilometre or a light year, that there would still be that constant 10,000N force between them?
Re:Actually, you CAN'T do that (Score:5, Interesting)
At higher energies, we can split that nucleus apart into protons and neutrons, and at still higher ones, into individual quarks
In one sense that seems to be something you really can't do. The force between free quarks increases with distance to about 10,000N, then remains constant (no, I have no idea how this makes any sense, but it's what I read). Any force sufficient to tear two quarks apart is sufficient to generate new quarks which then bind with the "free" quarks. So you never see quarks by themselves.
IANAP, though. Does the above really mean that if you had two free quarks separated by a kilometre or a light year, that there would still be that constant 10,000N force between them?
Plus that we are not even sure quarks are individual things. They might just be eigenvalues of particle properties, nice to calculate on, but not necessarily anything real in themselves.
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The top quark can exist without hadronizing, so the properties of "naked" quarks can be studied. Not sure if just an eigenvector can explain that.
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Your ideas are intriguing to me and I wish to subscribe to your newsletter.
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No, because sometimes several different models will fit all the available information. E.g., I prever the EGW multi-world interpretation of quantum physics, but the Copenhagen interpretation fits all the data just as well, and so do a few others...including such useless ones as "SuperPredestinationsim", "Solipsism", and "God is doing at all, and fudges things whenever he notices you're doing an experiment".
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The Everettian interpretation is certainly better than the Copenhagen interpretation, since it doesn't raise the measurement problem; however, it's no where near as simple (in the Occam's razor sort of way) as the Bohmian interpretation.
However, I think the history of physics should teach us that different interpretations are often different facets of the same thing. Compare Lagrangian and Hamiltonian mechanics, for example. They are both accurate (at least for our universe), but quite different in their ap
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What is a real individual thing? In the end, if we can model it and we can measure it, it's about as real as anything in our world can be.
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Any force sufficient to tear two quarks apart is sufficient to generate new quarks which then bind with the "free" quarks.
Sounds like the War on Terrorism in a microscopic edition. Fractal universe confirmed!
Re:Actually, you CAN'T do that (Score:4, Informative)
In one sense that seems to be something you really can't do. The force between free quarks increases with distance to about 10,000N, then remains constant (no, I have no idea how this makes any sense, but it's what I read).
IAAP, and you can "separate" a nucleon into constituent quarks in a sense. You're right in that you can't take them a kilometer apart because of the range behavior of the strong nuclear force that you cite. Instead, you create extremely high energy density region that makes the nucleons lose their identity, and the constituent quarks are free to interact with each other (a Quark-Gluon Plasma). This is done by colliding heavy ions, which creates a high energy density region that has some extent to it (as opposed to proton-proton collisions). The quarks can then "condense" out of this plasma into exotic things like pentaquarks.
Re:Actually, you CAN'T do that (Score:5, Informative)
You can't ever get two quarks very far apart. That property arises because the gluon, the force carrier for the strong force, has a strong charge of it's own. That's as if photons were electrically charged. When two quarks exchange virtual gluons the gluons exchange virtual gluons with everything around as well. The bigger the distance between the quarks, the more space for colour charged gluons between them, so the stronger the force.
When you pull two quarks further and further apart, at some point it's energetically favourable for a couple of virtual quarks to pop into existence and you end up with a couple of mesons instead of two free quarks. That's what happens in accelerators: nobody ever sees quarks, they see sprays of particles that indicate a hadron was blown apart and the constituent quarks then reformed into hadrons.
It's called colour confinement: https://en.wikipedia.org/wiki/... [wikipedia.org]
Re:Actually, you CAN'T do that (Score:4, Funny)
"You can't ever get two quarks very far apart. That property arises because the gluon, the force carrier for the strong force, has a strong charge of it's own. "
If you tried to separate "it" from "is", will the force generate new apostrophes?
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"You can't ever get two quarks very far apart. That property arises because the gluon, the force carrier for the strong force, has a strong charge of it's own. "
If you tried to separate "it" from "is", will the force generate new apostrophes?
Pedantry AND wit - what is /. coming to?
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According to Wikipedia [wikipedia.org] it's because gluons, which mediate the Strong Force interaction between quarks, also feel said force themselves (that is, they carry color charge(. So rather than disperse with distance like, say, photons do, they tend to stick together and form "ropes".
So it's analogous to how a flashlight loses power faster than a laser.
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Not a summary (Score:5, Informative)
This is not a summary, but a teaser. Let's keep that kind of bullshit off Slashdot.
Actual summary:
"Recently, the existence of pentaquarks, predicted by quantum chromodynamics, was confirmed. This sortof validates quantum chromodynamics. [Intro to quantum chromodynamics]. We could find many more particles predicted by quantum chromodynamics in the future!"
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Re:Not a summary (Score:4, Informative)
...where the authors treat hypothetical particles and theoretical particles interchangeably...
FTFY
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You got your hypothesis in my theory!
You got your theory in my hypothesis!
Alas, the end result isn't a Reese's cup.
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Mmmm Reese's.
Darn you!
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So the fuck what?
I read all the words (Score:1)
Gadgets (Score:2)
"Individual Quarks" (Score:2)
TFS lost me right there. There is No Such Thing(tm)