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# StrongNuclear forces and "Colour." of quarks. watch

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1. The strong nuclear force is due to gluons, so much I have caught. However, I fail to understand how the colours can add up to white in a neutron or a proton.

The problem is that wereas you need three colours to get white (Red Green and Blue ) A proton has two up-quarks and one down-quark. Thus if you are to get white either the up-quark or the dowquarks will have to carry two colours. However, no matter what colours you assign to the up-quarks and down-quarks respectively, it doesnt fit with both the neutron and proton. Either the Proton woant be "white" or the Neutron woant be "white".

I have a couple of possible explanations:

1: Colours may vary among baryons of the same type.
2: The magnitudes of the colours may vary among baryons of teh same type.
3: The colours do not have to be present in propper proportions to give white, you only need some ammount sof each colour.

Could anyone help me here?
2. (Original post by Jonatan)
However, no matter what colours you assign to the up-quarks and down-quarks respectively, it doesnt fit with both the neutron and proton.
why not? you can have a red up quark, a green up quark, and a blue down quark. that makes a white proton.
3. (Original post by elpaw)
why not? you can have a red up quark, a green up quark, and a blue down quark. that makes a white proton.
But taht would imply that a quarks colour is not determined by the type of quark, and then I quite honestly dont see the point in the first place since it would not determine which quarks could combine. What prevents ( as an example) three up-quarks from combining into a baryon?
4. (Original post by Jonatan)
But taht would imply that a quarks colour is not determined by the type of quark, and then I quite honestly dont see the point in the first place since it would not determine which quarks could combine. What prevents ( as an example) three up-quarks from combining into a baryon?
you are right. colour does not depend on the type of quark.

its like electrons with charge and spin: spin is independent of charge.

likewise in quarks: colour is independent of type-of-quark.

as for 3 up quarks: they do exist: it's the delta++ baryon

(look here for a list of all the baryons)
5. (Original post by elpaw)
you are right. colour does not depend on the type of quark.

its like electrons with charge and spin: spin is independent of charge.

likewise in quarks: colour is independent of type-of-quark.

as for 3 up quarks: they do exist: it's the delta+ baryon
Really? I did not know that. Can a quark change colour during an interaction? And also, is there anything preventing a 4-quark baryon, consisting of two anti-quarks and two normal quarks ?
6. (Original post by Jonatan)
Really? I did not know that. Can a quark change colour during an interaction? And also, is there anything preventing a 4-quark baryon, consisting of two anti-quarks and two normal quarks ?
yes, a particle can change colour (it's called the strong nuclear force, i.e. the gluon carries its colour to another particle, making the source and recipient particles change colour). as for 2 quark/2 antiquarks, i dont know if they exist. but pentaquarks (a meson and a baryon combined thingymajig) do exist: http://news.bbc.co.uk/1/hi/sci/tech/3034754.stm

( i have a suspicion that you can get the following quark combinations: 2, 3, 5, 8, 13, .... if you catch my drift; i dont know why, but it's a pattern seen in nature, and it seems "nice". however, the 5, 8, 13, ... ones are highly unstable and therefore very rare. it also explains why you cant have quadroquarks)
7. (Original post by elpaw)
yes, a particle can change colour (it's called the strong nuclear force, i.e. the gluon carries its colour to another particle, making the source and recipient particles change colour). as for 2 quark/2 antiquarks, i dont know if they exist. but pentaquarks (a meson and a baryon combined thingymajig) do exist: http://news.bbc.co.uk/1/hi/sci/tech/3034754.stm
Yes, I read about the pentaquark, and thats why I asked about the quadraquark. Interesting stuff this. Who knows, maybe some day we will be discussing femto-technology rather than nano-technology.
8. (Original post by elpaw)
yes, a particle can change colour (it's called the strong nuclear force, i.e. the gluon carries its colour to another particle, making the source and recipient particles change colour). as for 2 quark/2 antiquarks, i dont know if they exist. but pentaquarks (a meson and a baryon combined thingymajig) do exist: http://news.bbc.co.uk/1/hi/sci/tech/3034754.stm

( i have a suspicion that you can get the following 5 quark combinations: 2, 3, 5, 8, 13, .... if you catch my drift; i dont know why, but it's a pattern seen in nature, and it seems "nice". however, the 5, 8, 13, ... ones are highly unstable and therefore very rare)
Oh god, I just recalled my Mathematics teachers comment to the equation e^i*pi + 1 = 0 "It is so beatiful you could become religious!" - Iversen

Btw: I have forgotten the name of teh above series, but if you are correct we should expect to see hadrons with quark counts of 21, and 36 as well.
9. (Original post by Jonatan)
Btw: I have forgotten the name of teh above series, but if you are correct we should expect to see hadrons with quark counts of 21, and 36 as well.
it's called the fibonacci sequence. i was just including it because it could explein why there are no quadroquarks, but my hypothesis (more like suspicion!) has no scientific backing (yet). as for 21-quarks and 36-quarks, i think they are a long time away, seeing as our current accelerator technologies can only just resolve pentaquarks.
10. (Original post by elpaw)
it's called the fibonacci sequence. i was just including it because it could explein why there are no quadroquarks, but my hypothesis (more like suspicion!) has no scientific backing (yet). as for 21-quarks and 36-quarks, i think they are a long time away, seeing as our current accelerator technologies can only just resolve pentaquarks.
Hehe. Well, anyways I would love to "see" a femtotube made out of a continious sequence of quarks. Anyways, looking at that site you put here I just think I learned mroe physics than I have the last 3 months in the IB HL course Long live the Internet!

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