First Particle Comprising Four Quarks Discovered 111
ananyo writes "Physicists have resurrected a particle that may have existed in the first hot moments after the Big Bang. Arcanely called Zc(3900), it is the first confirmed particle made of four quarks, the building blocks of much of the Universe's matter (abstract one, abstract two). Until now, observed particles made of quarks have contained only three quarks (such as protons and neutrons) or two quarks (such as the pions and kaons found in cosmic rays)."
Yahoo! (Score:5, Funny)
I always vowed to open a tall cool one on the day they found a four-quarker.
4.5 litres. Hic. (Score:5, Funny)
Four quarks? That's a Galuon, isn't it?
The Gillette Co. says (Score:5, Funny)
Fuck everything, we're doing five quarks.
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Yeah, we got it, but thanks for being 'that guy' who's compelled to explain the punchline of a joke.
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I've seen enough people here not get (what I consider to be very) obvious jokes that I don't see the problem.
And most of the time it doesn't appear to be a language or cultural issue either.
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You're absolutely right... we should always explain the punchlines to jokes just in case someone doesn't 'get it'. We should incorporate it into other media as well. Imagine how much funnier movies/TV/video games etc. would be if they paused after every joke to explain why you should laugh just in case anyone was left out.
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I've seen enough people here not get (what I consider to be very) obvious jokes that I don't see the problem.
It is called humor impairment [chicagotribune.com]. It is a common affliction.
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feeding obvious troll (Score:2)
and before that, SNL:
http://boingboing.net/2005/09/14/gillettes-5blade-raz.html [boingboing.net]
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Ohhh, someone who ready boing boing! Quick Schmedley! Fire up my Friendster and MySpace! I think we may be able to issue a communicaé!
Re:The Gillette Co. says (Score:5, Funny)
And Gillette will get promptly their ass sued by Apple who has already patented the "look and feel" of particles comprised of more than three quarks.
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Fuck Gillette, we're doing six quarks.
http://www.dorcousa.com/ [dorcousa.com]
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That's clearly derivative work son. Patent infringement!
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No thanks. I've used Dorco razors and although they don't degrade particularly quickly, this is attributable to the fact that they're pre-dulled for your inconvenience. If they can't sharpen a blade, I suspect they can't deal with subatomic particles very well either.
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Indeed, I interviewed a group investigating the pentaquark at SPring-8. This was posted on my blog here: http://www.lookingatnothing.com/?p=366 [lookingatnothing.com]
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Pentaquark (Score:3)
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Aw, now you are being rational. C'mon, when somebody sees a transluminal neutrino, traps a magnetic monopole, measures a signal that might possibly be the long lost Higgs boson, you can't go around doubting it. Where would climate science be if one doubted the spaghetti-snarl output of all of the GCMs and Hansen's predictions of 5 meter SLR by 2100? Where would medicine be if we doubted that oat bran and fish oil pills prevent heart attacks? Where would the Middle East be if all of a sudden all of the M
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These guys still claim to see them: http://www.lookingatnothing.com/?p=366 [lookingatnothing.com]
Continues to confirm current theories (Score:5, Interesting)
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So someone already knows all this stuff and is just playing the "i told you so" game right!
Re:Continues to confirm current theories (Score:5, Informative)
That's been that state of particle physics for decades. I don't think anyone likes the Standard Model, it's inelegant and has more "elementary" particles than can be easily memorized, but it keeps making accurate predictions. Attempts of think of a simpler model from which one could deduce all the details of the standard model have all failed so far in making better predictions (and in the case of String Theory, turned out to be vastly more complex than what they were trying to simplify).
Re:Continues to confirm current theories (Score:4, Interesting)
Well said. But if the various numbers that make up the SM are axiomatic, it's interesting to consider what the universe might look like if some (or all) of those axioms were changed. Sort of like considering what Euclidean geometry would look like if the parallel postulate were not true, and consequently coming up with spherical and hyperbolic geometry.
After all, there's nothing to say that "other" Universes have to work the same way as ours -- even the mechanics of universe formation might be different.
Re:Continues to confirm current theories (Score:5, Informative)
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Agreed, those books are awesome... and despite the subject matter being ridiculously complex he doesn't go over the top and make it an unintelligible physics lecture. He just surmises how the universe might work and puts a story in the middle of it. One of the more creative works I've ever read.
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Free parameters not the issue: SM is wrong! (Score:5, Insightful)
I don't think anyone likes the Standard Model, it's inelegant and has more "elementary" particles than can be easily memorized, but it keeps making accurate predictions.
Actually that is not really true: just about anyone can do a very simple experiment which is inconsistent with the predictions of the Standard Model. Pick up an object and then let it go. There is nothing in the Standard Model which will predict the behaviour you observe. That's why we physicists don't like it. Parts of it are extremely elegant - e.g. the Higgs mechanism - but since it can't explain gravity we know it is wrong and yet we still cannot find any better model that works for all the other fundamental forces and gravity...not to mention explaining other phenomena like Dark Matter, matter/anti-matter asymmetry of the universe, baryon number violation... etc. The number of particles and free parameters is a minor issue!
Re:Free parameters not the issue: SM is wrong! (Score:5, Informative)
Gravitons are not a Standard Model particle, though you can tack them on to the Standard Model to partially explain some gravitational behavior (though not without introducing mathematical problems). The link between Standard Model (and variants) field theories and General Relativity is still missing: one can calculate how particles act within gravitationally bent spacetime, but there is no "microscopic" model for how particles themselves bend the spacetime around them as you approach high enough energies for that to be relevant.
SM precludes gravity like SR precludes FTL travel (Score:3)
The Standard Model doesn't preclude gravity
That is like arguing that special relativity does not preclude faster than light travel. You cannot add FTL travel to SR without inconsistencies (like breaking causality) but you technically can add it. You could also imagine developing a framework which expanded on SR and allowed FTL velocities. In the same way adding gravity to the Standard Model creates inconsistencies (renormalization cut-off) but you can imagine a framework which expands on the SM and somehow incorporates gravity.
The only differenc
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Being able to see gravity exists is a ways away from seeing that gravity is described by GR, which is what the conflict comes down to.
Eh? I don't know what you were discussing but I was discussing that the SM cannot explain gravity not whether General Relativity accurately describes gravity. Since the SM cannot explain gravity it cannot explain why an object will fall when dropped. Could you bolt some monstrosity onto the SM to explain that one situation? Possibly but I doubt it and, even if you did, what you added would not be gravity.
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I've yet to really understand the Higgs mechanism - does it explain why binding energy has/is inertia? I think it would be pretty unsurprising at this point if we one day get a good theory of "more elementary" particles than the standard model, in which all mass is binding energy. Point particle mass seems like the odd exception now. But how do all these different kinds of binding energy each give rise to mass/inertia? Does every field couple to the Higgs field in some way? It just seems very strange.
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As a non-physicist, my understanding of the Higgs mechanism is pretty weak, but...
The way I understand it the generic idea of the Higgs mechanism isn't simply restricted to be a "mass-generating" mechanism, although the most interesting Higgs mechanism that are searched for are the ones that can suggest electro-weak symmetry breaking which gives non-zero rest masses to W and Z bosons. The reason why most folks are searching for something that can describe this is that W and Z boson have the largest masses
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That's been that state of particle physics for decades. I don't think anyone likes the Standard Model, it's inelegant and has more "elementary" particles than can be easily memorized,
You have poor memory :-)
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Plus the gauge bosons (photon, gluons, W, Z), and the Higgs, which seem to have escaped your memory. Apparently, the Standard Model particles are a bit harder to memorize than you think...
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Well they did not really escaped my memory and I can add a precision to your precision: the weak interaction bosons are W+, W- and Z.
But are are gauge bosons fundamental particles? They are not used to build compound particles, this is why I did skip them.
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But are are gauge bosons fundamental particles?
Yes, they are considered fundamental/"elementary" by the same logic that the others are: that they are not themselves built of other fundamental particles.
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The gauge bosons are excitations of a quantized gauge field, but gauge fields are not real
Well, something underlying them must be real in the sense of being able to affect fermions, otherwise my Wi-Fi, radio, and light bulbs wouldn't be working....
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It is amazing that these experiments continue to confirm current theories. I was hoping they would find some strange thing that didn't fit, so we could understand why current theories don't explain everything. Maybe next time.
It could just be that, particularly when dealing with particle physics, one can only find what one is looking for. Or put differently, you are unlikely to discover something that the theories don't predict, because all of the equipment and tests have been designed to confirm what the theories predict. Of course that is how the scientific method is supposed to work. You come up with a hypothesis, you devise and experiment to test that hypothesis, you repeat it numerous times to confirm the results.
In short,
Re:Continues to confirm current theories (Score:4, Funny)
The physics is cool, but I'm just excited that someone on the Internet used comprise correctly!
Naturally - they didn't want to comprise their principals!
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LOL .... (Score:5, Funny)
There ... are ... 4 ... quarks!
And, kidding aside, anyone care to put a meaning for this into layman's terms? Is more quarks == more energetic?
I'm afraid these particles have always been a little too abstract to grok what this means.
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The layman's answer is that it has no meaning. If you follow the link, it shows a pretty picture about quark arrangements, only the 'Baryonic' section matters at all to a layman, and most baryonic matter still doesn't matter.
For an interested layman, it just means 'these Legos can click together in more ways than we have recorded.'
For any more depth than that, you don't count as a layman anymore, so go read the root papers.
Re:LOL .... (Score:5, Informative)
anyone care to put a meaning for this into layman's terms?
To my mind the issue is color balance. No, really. Quarks have a property called "color" (not in any way related to visible colors), which needs to be balanced in order to get a stable particle. (It's a consequence of the non-abelian SU(3) gauge group of the strong nuclear force. Aren't you glad you asked?)
The upshot is that to get a stable particle, you need to have a set of blue+anti-blue, or red+anti-red, or green+anti-green, or blue+green+red or anti-blue+anti-green+anti-red quarks. This is the origin of the 2 quark (color+anti-color) or 3 quark (all colors) particle. (Of course, this is a simplification - because of gluons the colors of the particles are constantly swapping around, but in ways that maintain the color balance.)
Having four quarks upsets this notion. You need some way of balancing the color, and the "traditional" ways of doing it won't work. My guess is that this new particle is probably something like a blue+anti-blue+red+anti-red. As the news article mentions, it's apparently still up in the air whether this should really be considered a true four quark particle, or simply two particles (blue+anti-blue & red+anti-red) in very close association.
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Let's try a car analogy.
Quarks are like cars. When an accident occurs with a Ford Pinto, a Barbie Convertible (with Ken), and a D-9 Cat g and they lock bumpers, they merge and you end up with a Subaru Legacy Outback.
See, quarks can make sense in the real world too! Well, at least as much sense as they normally do.
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Thank you, I believe I actually followed that.
So if it's a union of two mesons, I'm calling it a mesonicule, but I'm hoping for tetraquark, because that just sounds awesome and makes we want to say "10 quatloos on the newcomer". ;-)
onwards to the pentaquark! (Score:2)
Can five blades [wikipedia.org] be far behind?
Fractional charges? (Score:1)
Would particles like this have fractional electrical charges? +4/3, -4/3, etc?
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I'm wondering how the hell its color charge works, myself.
As I said in the response to the gp, tetraquarks consist of two quarks and two anti-quarks, the same quark content as two mesons. It is therefore possible for them to be arranged in a colorless state, which is of course demanded by QCD. (eg. a tetraquark could consist of a red quark, a blue quark, a red anti-quark, and a blue anti-quark. Of course, these colors are constantly changing as a result of the gluon field, but the tetraquark will remain overall colorless, just as mesons do.)
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Of course after I actually clicked on the article, that made sense. Now I'm wondering how this is different than two mesons "stuck together". Which, according to TFA, it might just turn out to be.
Well, the binding energy (which would be reflected in the mass of the particle) would be very different for two mesons stuck together. In a tetraquark, the four quarks would be bound together with essentially the same energy, whereas with two mesons stuck together, there'd be much stronger binding between the two quarks in a meson than between the mesons. But even that would be interesting, as I'm not sure a state with two mesons stuck together have been observed. (Of course, baryons similarly stuck toge
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Would particles like this have fractional electrical charges? +4/3, -4/3, etc?
No. The "tetraquarks" that are being talked about in this article consist of a pair of quarks and a pair of antiquarks. (i.e., the same quark content as two mesons). Quarks have charges of +2/3 or -1/3, while anti-quarks have charges of -2/3 or +1/3. Whenever you put together 2 quarks with 2 anti-quarks, you'll always get whole number charges, i.e. -2, -1, 0, 1, or 2. (Try it.)
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Clones? On MY garbage scow?! (Score:2)
anyways, thanks for posting the irrelevant reminiscence.
Hang on (Score:5, Informative)
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There's no real way to "confirm" the number of quarks. Quark number is not a conserved quantum number, so every particle exists as a superposition of different quark numbers. This is particularly problematic if you probe a particle at very high energies; at sufficiently high energies, every hadron (including the humble proton) appears to be a soup of quark-antiquark pairs bubbling out of the vacuum. However, you should be able to make predictions of what the particle's properties will be if it's mostly like
Celebration (Score:1)
Wow! A quad-quark particle. That must be as exciting for Physicists, as the quad-screwdriver drink I discovered years ago. (or at least I was told I was very happy).
On particle resurrection (Score:2)
Physicists have resurrected a particle that may have existed in the first hot moments after the Big Bang
I'm pretty certain that these particles do appear every now and then, given how the universe itself acts like a giant particle accelerator - like a much larger, much more powerful, and much much more badass particle accelerator, to be more specific.
Three quarks for Muster Mark! (Score:2)
Sure he hasn't got much of a bark
And sure any he has it's all beside the mark."
-- James Joyce, Finnegans Wake [finwake.com]
Four quarks screw up Murray Gell-Mann’s perfect “allusion [takeourword.com]”.
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not really. there are 6 types of quark (plus 6 anti quarks). before we had only observed them bound 2-quark and bound 3-quark states, (though there have been several claimed 5-quark observations that have not stood up). Now we have 2 groups claiming to see a 4-quark state
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Four quarks screw up Murray Gell-Mann’s perfect “allusion [takeourword.com]”.
Comic Sans screws up Murray Gell-Mann's perfect allusion. My eyes!
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The green background is not helping either! Website like that make me pine for a good old fashioned monochrome monitor. I think I am going to dig out my Hercules Graphics Card.
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I don't care (Score:2)
As long as my car still gets 40 rods to the hogshead then that's the way I likes it.
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pffft, I have a Zc(2900) in my garage.
So, Four Quarks and a Penny? (Score:2)
...still don't know her last name...
There are (Score:1)
Why does this make me think of..... (Score:1)
...Deep Space Nine?
they keep changing this (Score:2)