Electrons and Quarks

[colinha]

Electric force charges on quarks are +2/3 and -1/3 for up and down variants.
The charge on an electron is -1
Quarks balance in groups of 3 to give a net charge of +1 or zero in nuclei in atoms.
The fact the charges on electrons and 3 quark nuclei match allows atoms to exist.
My question is why these apparently unrelated particles balance in this way. Is it posible that the quarks could have had charges of 3/4 or 7/8 or some other value and hence atoms would not have existed or is there some fundamental reason that these charges were inevitable?

[jake-the-peg]

I think it's pretty clear that there is a relation here.

These are the same type of particles so it's not really all that surprising that one of their properties sums up to unity.

What's more interesting is that electrons have exactly the same charge.

To understand this you need to be able to connect the electromagnetic force (from which we get the electric charge) with the Strong Nuclear Force which gives us the quarks and gluons.

As yet we do not have such a theory that is generally accepted

[R1Geezer]

well 95% of the matter/energy universe is not atoms so I'd say there's every chance of other configurations. So I'd say they what we currently call atoms are the exception rather than the rule. Approx 35% of matter is dark matter, ie exerting influence but thus far and unknowln configuration.

I'm sure our resident Nuclear Scientist Jake will be along soon to give a more thorough answer.

[jake-the-peg]

Well particles are either composed of quarks or leptons

The other type missing from Colin's description are mesons which are the Pions and Kayons which are shortlived and are composed of one quark and anti-quark (again with a charge of 1 or 0 )

Fundamentally though we see a quantised universe. That is that quantities such as mass, energy etc. come in discrete bundles.

So really it's not odd that charge should be that way too. Admittedly it's odd that we should only be able to observe this fundamental charge in multiples of 3 but that's probably just because we don't understand it's origin - I dare say that if we did it'd be obvious.

I don't think dark matter is relevant here because it doesn't seem to be charged.

It may even turn out to be neutrinos

[R1Geezer]

Well I was using the dark matter/energy to highlight the fact that when the questioner says "......hence atoms would not have existed", that that is not far off the case!

[beso]

The one third factor is arrived at by sorting the short lived particles in the schrapnel of atomic collisions. The three quarks proposed have never been observed but only inferred from the match between the measured and theoretical combinations of particles produced.

[beso]

To clarify. Three quarrks make a proton or neutron but there are two main quarks. However there are actually six quarks and six antiquarks known.

[beso]

That is even worse. D@mned wine.
Nevermind

[jake-the-peg]

Not sure if I quite buy the notion that quarks have never been observed only inferred.

It's true you cannot observe free quarks on their own but scattering experiments show them up.

If you hold a bag containing 3 billiard balls you know what's in it. You don't have to open the bag and take them out individually to be sure that they're there!

[colinha]

What was bothering me was that the way 1/3 and unit charges combine to construct atoms looks designed.
Being a good atheist, I would prefer a reason from physics to explain why nature is like this.

[jake-the-peg]

I fear you'll need to be a good physicist first!

When Mendeleev saw the pattern in the elements it was indicative of a deeper structure that explained it.

We see the pattern in subatomic particles which is why we think there is a deeper structure explaining this.

It's a jumping off point for string theory where all fundamental particles are tiny 1 dimensional strings with different "vibrational" modes that give them their properties.

Proving it though is proving er challenging to say the least