# How is proton formed? What force holds 3 quarks together?

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#### jccc

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##### How is proton formed? What force holds 3 quarks together?
« on: 18/07/2014 07:53:07 »
Assume 3 quarks made proton is true, 2 u quarks carrie 2 x 2/3 positive charge, 1 d quark carries 1/3 negative charge. Net charge +1.

What force holds them into a proton? Electrostatic force?  Why electrons not join the party?

Who is the doorman keeps electrons out?

#### evan_au

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##### Re: How is proton formed? What force holds 3 quarks together?
« Reply #1 on: 18/07/2014 09:40:43 »
Quote
What force holds them into a proton? Electrostatic force?
Quarks are held together by Gluons. The Gluon force is much stronger than the electrostatic force (otherwise the two positive quarks would repel each other, and blow the proton apart).

Quote
Why electrons not join the party?  Who is the doorman keeps electrons out?
The wavelength of an electron (or uncertainty of the electron's position) is so large that the electron cannot be localised to within the 0.9 femtometer which is the size of a proton.

#### jccc

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##### Re: How is proton formed? What force holds 3 quarks together?
« Reply #2 on: 18/07/2014 17:41:02 »
Quote
What force holds them into a proton? Electrostatic force?
Quarks are held together by Gluons. The Gluon force is much stronger than the electrostatic force (otherwise the two positive quarks would repel each other, and blow the proton apart).

Quote
Why electrons not join the party?  Who is the doorman keeps electrons out?
The wavelength of an electron (or uncertainty of the electron's position) is so large that the electron cannot be localised to within the 0.9 femtometer which is the size of a proton.
Do you seriously believe those?

#### chiralSPO

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##### Re: How is proton formed? What force holds 3 quarks together?
« Reply #3 on: 18/07/2014 17:48:07 »
Do you seriously believe those?

yes.

At least it is a good description. At this point we have no actual way of directly "seeing" this, but the model fits the experimental probes very well.

#### UltimateTheory

• Sr. Member
• 107
##### Re: How is proton formed? What force holds 3 quarks together?
« Reply #4 on: 18/07/2014 18:04:03 »
jccc, learn how to calculate decay energy,
this way you will be able to calculate which isotope can decay through which branch.
One of decay modes is electron capture.
In this process proton and electron from the closest orbit are joining to neutron (inside of nucleus, not free neutron).

f.e.
Beryllium-7 + e- -> Lithium-7 + Ve + 0.861893 MeV
(this isotope has exclusive decay mode electron capture, no others are allowed)

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

On bottom you have full periodic table for other elements isotopes.

Electron capture is showed as EC in decay mode column.
« Last Edit: 18/07/2014 18:06:39 by UltimateTheory »
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#### PmbPhy

• Neilep Level Member
• 2788
##### Re: How is proton formed? What force holds 3 quarks together?
« Reply #5 on: 18/07/2014 19:15:49 »
Assume 3 quarks made proton is true, 2 u quarks carrie 2 x 2/3 positive charge, 1 d quark carries 1/3 negative charge. Net charge +1.

What force holds them into a proton? Electrostatic force?  Why electrons not join the party?

Who is the doorman keeps electrons out?
There are four fundamental forces in nature. Each force is mediated by a particle. Gluons are held together by the same force that holds nucleons together. These interactions are

Force                 Mediator
--------------------------------------
Strong                Gluon
Electromagnetic   Photon
Weak                  W and Z bosons
Gravitational        Graviton
--------------------------------------

Quote from: UltimateTheory
jccc, learn how to calculate decay energy,..
Electrons are not part of the interaction which holds protons together or what mediate the attraction between quarks.
« Last Edit: 20/07/2014 06:41:39 by evan_au »

#### jccc

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##### Re: How is proton formed? What force holds 3 quarks together?
« Reply #6 on: 18/07/2014 19:20:36 »
Do you seriously believe those?

yes.

At least it is a good description. At this point we have no actual way of directly "seeing" this, but the model fits the experimental probes very well.

A group of charged particles meet, u quark and d quark and gluons are having group sex, electrons are watching. Because of his wave length is too big? How about those guys only carries 1/3 charge? Are they white?

#### UltimateTheory

• Sr. Member
• 107
##### Re: How is proton formed? What force holds 3 quarks together?
« Reply #7 on: 18/07/2014 21:39:58 »
jccc, I was referring to second part of your question:

"Why electrons not join the party? Who is the doorman keeps electrons out? "

Electrons are occasionally captured by nucleus, and it depends on isotope content.
We can PREDICT exactly which nucleus will capture electron.
I am giving you knowledge how to predict this event.
« Last Edit: 20/07/2014 06:40:13 by evan_au »
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#### jccc

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• 990
##### Re: How is proton formed? What force holds 3 quarks together?
« Reply #8 on: 19/07/2014 01:17:03 »
We all truth seekers in darkness, some have sharper eyes, that's it.

Please don't calling names, all my teachers.

Electrons are occasionally captured by nucleus, please give detail, mechanism etc.  Why not captured all the time?

#### UltimateTheory

• Sr. Member
• 107
##### Re: How is proton formed? What force holds 3 quarks together?
« Reply #9 on: 19/07/2014 01:30:03 »
Electrons are occasionally captured by nucleus, please give detail, mechanism etc.  Why not captured all the time?

I gave you calculations in #4 posts. You can calculate literally any isotope decay mode in the world..

Electron capture must obey (at least) energy conservation, baryon number, and lepton number conservations.
« Last Edit: 19/07/2014 01:42:03 by UltimateTheory »
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#### PmbPhy

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##### Re: How is proton formed? What force holds 3 quarks together?
« Reply #10 on: 19/07/2014 09:11:41 »
Quote from: jccc
Electrons are occasionally captured by nucleus, please give detail, mechanism etc.  Why not captured all the time?
Think about it like this. It's called electron capture for a very good reason. Electron capture as you know is defined as the capture of an electron by a proton which then changes into a neutron with the emission of an electron neutrino. The process is
http://en.wikipedia.org/wiki/Electron_capture

$$p + e^{-} -> n + \nu$$

In order for the electron to be captured by the nucleus the electron must be somewhere near it. That's most likely for electrons in the K and L electron shells. In fact nearly all electron capture comes from electrons in the K shell. The reason for this is because probability is proportional to the square of the wave function integrated over the volume of the nucleus. It's most significant for 1s electrons of the K shell or, with much lower probability, the 2s electrons of the L shell. The electrons can't be thought of as being in the region of the nucleus constantly. If quantum mechanics was like than then
I can imagine that some strange things might occur.
« Last Edit: 20/07/2014 07:07:54 by evan_au »