# How big is a quark?

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Posted (edited)

So quark is the smallest particle available that can be seen. But how big is a quark and are they all the same in size? Can we have a big quark and a small quark? Please let me know, thanks

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Quarks and electrons are considered point particles. They have no known internal structure, and experiments are consistent with them having no size.

But their interactions have a range, and you have the Heisenberg Uncertainty Principle, which complicates things.

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1 hour ago, swansont said:

Quarks and electrons are considered point particles. They have no known internal structure, and experiments are consistent with them having no size.

But their interactions have a range, and you have the Heisenberg Uncertainty Principle, which complicates things.

Is their range the size of the particle they make up?

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2 hours ago, StringJunky said:

Is their range the size of the particle they make up?

It's complicated. The interaction between quarks has an infinite range, as gluons are massless. But there's more going on

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Posted (edited)
25 minutes ago, swansont said:

It's complicated. The interaction between quarks has an infinite range, as gluons are massless. But there's more going on

Thanks. Is this  the relevant reason?:

Quote

The strong force acts between quarks. Unlike all other forces (electromagnetic, weak, and gravitational), the strong force does not diminish in strength with increasing distance between pairs of quarks. After a limiting distance (about the size of a hadron) has been reached, it remains at a strength of about 10,000 newtons (N), no matter how much farther the distance between the quarks.[5] As the separation between the quarks grows, the energy added to the pair creates new pairs of matching quarks between the original two; hence it is impossible to create separate quarks. The explanation is that the amount of work done against a force of 10,000 newtons is enough to create particle-antiparticle pairs within a very short distance of that interaction. The very energy added to the system required to pull two quarks apart would create a pair of new quarks that will pair up with the original ones. In QCD, this phenomenon is called color confinement; as a result only hadrons, not individual free quarks, can be observed. The failure of all experiments that have searched for free quarks is considered to be evidence of this phenomenon.

That article was quite good for me as it's defined some unfamiliar words that I've seen a few times but not understood..

Edited by StringJunky

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Posted (edited)

Couple questions which you can ask, and get reply from us, concerning quarks from Standard Model:

- which generation?

- what is charge?

- how much rest-mass?

- is it stable or unstable (does it decay)?

- if it's unstable, to what it decays?

- which bosons can mesons can be constructed by them?

Particle that has more mass-energy (rest-mass) can decay to particle that has smaller mass-energy. e.g. down quark has more mass-energy than up quark, that's why it decays to up quark emitting electron and antineutrino.

Particles from 2nd and 3rd generation, have enormous higher mass-energy than from 1st generation.

Particles from 3rd generation decay to 2nd generation and sometimes to 1st generation directly.

Particles from 2nd generation decay to 1st generation of particles.

Leptons from 2nd generation decay only to leptons from 1st generation. Not enough mass/energy.

Leptons from 3rd generation decay to other leptons but also to quarks/antiquarks. Enough mass/energy.

Edited by Sensei

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1 hour ago, Sensei said:

- which bosons can mesons can be constructed by them?

Little fix. It should be "which baryons and mesons can be constructed by them?"

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9 hours ago, StringJunky said:

Thanks. Is this  the relevant reason?:

That article was quite good for me as it's defined some unfamiliar words that I've seen a few times but not understood..

Yes, that's the complicated bit that I wasn't going to try and explain myself.

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1 hour ago, swansont said:

Yes, that's the complicated bit that I wasn't going to try and explain myself.

cheers.

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