What role do quarks have on the atomic level?

[kirbsrob]

What is it?

[ajb]

The force responsible to atomic physics is the electromagnetic force. The only direct role I can see is the fact that the charge of the quarks that build a nucleus define the total charge of that nucleus. The strong force (or the residual strong nuclear force) do not play any direct role in atomic physics.

[derek w]

Is the force that holds the quarks confined and the strong force the same thing?

[swansont]

Strong force, yes. Residual strong force (binding protons and neutrons together), no.

 

http://en.wikipedia.org/wiki/Strong_interaction

[Cosmobrain]

Why do quarks have to exist in the first place? It just makes things more confusing than they already are. Why three? (or two, if it is a meson, but anyway...) What is the nature of the strong interaction?

 

I think that unfortunately I'll never be able to understand nature

[swansont]

Why quarks exist isn't really a question science addresses. Our best (and quite successful) model for how things behave at that level is that they do, and their behavior follows certain rules.

[ajb]

Why three? (or two, if it is a meson, but anyway...)

This is a good question, and I don't think anyone has a good answer. However, you should be aware that there is the notion of an exotic baryon, which is basically a bound state of four or more quarks. I don't think there is much evidence of these states in nature and many would be very unstable.

 

What is the nature of the strong interaction?

We have a theory called quantum chromodynamics (QCD) and this should explain all the phenomena of the strong force and the residual strong nuclear force. However, most of the very successful methods employed in quantum electrodynamics don't work so well for QCD. Either one can build phenomenological models of the residual strong force, which should come as a limit of the full theory of QCD or one can place QCD on a lattice and use computers to solve the equations.

 

Either way, people do have some handle on many aspects of QCD.

[Cosmobrain]

We have a theory called quantum chromodynamics (QCD) and this should explain all the phenomena of the strong force and the residual strong nuclear force. However, most of the very successful methods employed in quantum electrodynamics don't work so well for QCD. Either one can build phenomenological models of the residual strong force, which should come as a limit of the full theory of QCD or one can place QCD on a lattice and use computers to solve the equations.

 

Either way, people do have some handle on many aspects of QCD.

Yes, but that's a fallacy. You are basically explaining the strong force using the strong force. QCD is a theory, but it doesn't really explain the true nature of that force. Just like electromagnetism doesn't really explain how particles can attract or repel each other. But it's ok, no one can answer such questions anyway

[imatfaal]

Yes, but that's a fallacy. You are basically explaining the strong force using the strong force. QCD is a theory, but it doesn't really explain the true nature of that force. Just like electromagnetism doesn't really explain how particles can attract or repel each other. But it's ok, no one can answer such questions anyway

[/quote

True nature is a question for metaphysics - physics deals in predictive models reinforced through correlation with experimental evidence.

 

On the QCD thing - no you are not quite right. Although QCD does explain the strong force with another model - this other model is at a more fundamental level. Rather than have the existence of the strong force as the most basic assumption; QCD works such that, amongst other things, the strong force emerges as a property of lower level interactions. This is the pursuit of physics - the explanation of things at lower and lower levels - ideas seem to have become more complicated (and they are definitely harder to understand) but these ideas rely on fewer assumptions

[ajb]

QCD is a theory, but it doesn't really explain the true nature of that force.

I disagree, the theory is the thing that truly does explain the nature of the force.

 

I think you are misunderstanding what theoretical physics is and what it can do. Your objections seem more philosophical and live in metaphysics, not theoretical phsyics.

[MirceaKitsune]

I haven't fully understood this myself. But from what I read, quarks are what make up particles and define what they are. The count as well as shape of quarks define the mass of a particle, its electric charge, and pretty much everything. Note that I'm only stating what I understood, don't take this for granted as I might be wrong.

 

In a documentary about the multiverse theory, I heard that the shape of quarks are what defines the properties of an universe. So in another universe, there might be 4 spatial dimensions and time is the 5th dimension... or "flatland" might literally exist. I find it a rather beautiful thought personally, if this really happens to be true.

[ajb]

I haven't fully understood this myself. But from what I read, quarks are what make up particles and define what they are.

Quarks are the main constituent of hardrons, that is baryons and mesons. You are right that the properties of quarks give rise to the properties of hardons and so should give us all the properties of nucleons and the atomic nuclei.