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)."
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:The Gillette Co. says (Score:2, Informative)
Re:The Gillette Co. says (Score:1, Informative)
Yeah, we got it, but thanks for being 'that guy' who's compelled to explain the punchline of a joke.
Re:LOL .... (Score:2, Informative)
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.
Hang on (Score:5, Informative)
Re:Continues to confirm current theories (Score:5, Informative)
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.
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.