The Strong Nuclear Force: Is my understanding correct?

[A M]

TL;DR

I want to write a student article specially for those who don't have a background in nuclear physics. I've been suggested to share my basic understanding & ask if they're correct.
I would be grateful if anyone could explain where my mistakes are:
(Please note that diagrams are designed just to give a simple imagination of the article & make it more understandable; they do NOT correspond precise information.)

The strong nuclear force is the strongest of the four basic forces in nature (the others are: the electromagnetic force, gravity, and the weak nuclear force). But it also has the shortest range, meaning that nucleons (protons & neutrons) must be extremely close (~1 fm) before its effects are felt.
The nuclear force can be explicated simply by analogy with the force between two small magnets: magnets are difficult to separate when stuck together, but once pulled a short distance apart, the force between them falls [almost] to zero.
This force between nucleons is done through the exchange of particles called mesons. As long as this meson exchange can happen, the strong force is able to hold the participating nucleons together.

https://www.physicsforums.com/attachments/2-jpg.248608/​

For the lightest nuclei, the energy of the strong force per nucleon generally grows rapidly; because when a nucleon is added to such a small nucleus, the strong force attracts it to all the other constituent proton/s and neutron/s. I.e. the nucleus is sufficiently small that by adding each nucleon, all the others feel stronger effect.

But this trend approaches a limit corresponding to that of larger nuclei, because the nuclear force is short-range and cannot continue to act across longer nuclear length scales. (Generally, by this force a nucleon can only affect its close neighbors.)
Except for the lightest nuclei that all the nucleons are close to each other, for heavier elements the nucleons in the interior of a nucleus have more neighboring nucleons than those on the surface. So, according to the fact 'the larger a nucleus, the smaller its ratio of surface area to volume ', the energy of strong force per nucleon generally increases with the size of nucleus. (But it grows more and more slowly depending on the changes of the ratio.)
References:
http://aether.lbl.gov/elements/stellar/strong/strong.htmlhttps://en.wikipedia.org/wiki/Nuclear_binding_energy

 

[mathman]

Strong force is a force between quarks. https://en.wikipedia.org/wiki/Strong_interaction

 

[A M]

Yes, but more precisely it is the force between the quarks of TWO nucleons.
(The interaction between the quarks of a single nucleon isn't called the strong nuclear force.)

 

[A M]

And as I've already included, this article is specially designed for those don't have much information about particle physics, so they do not know what exactly a quark is.

 

[nrqed]

Yes, but more precisely it is the force between the quarks of TWO nucleons.
(The interaction between the quarks of a single nucleon isn't called the strong nuclear force.)

There IS a strong nuclear force between quarks of a single nucleon, of course. This is what is mostly responsible for the interactions of the quarks within a nucleon.

 

[A M]

There IS a strong nuclear force between quarks of a single nucleon, of course. This is what is mostly responsible of the quarks within a nucleon.

Omg, it's getting worse and worse. if it IS the interaction between the quarks of a single nucleon, the fact that "the binding energy of a nucleus is is the energy due to the strong nuclear force, minus the disruptive energy of Coulomb force" is meaningless.

Or if that fact is true, "the strong nuclear force" in this article can be the simplified form of 'the strong nuclear force between the quarks of two nucleons', as I said.

[And it is important to keep in mind that this is an introduction topic; if I say the strong nuclear force is the interaction between quarks, then I should explain what a quark is, what kind of quarks nucleons are made of, and also its responsibility to hold quarks together to form other hadrons]

Do you really suggest me to get that technical about it?

 

[nrqed]

Omg, it's getting worse and worse. if it IS the interaction between the quarks of a single nucleon, the fact that "the binding energy of a nucleus is is the energy due to the strong nuclear force, minus the disruptive energy of Coulomb force" is meaningless.

Or if that fact is true, "the strong nuclear force" in this article can be the simplified form of 'the strong nuclear force between the quarks of two nucleons', as I said.

[And it is important to keep in mind that this is an introduction topic; if I say the strong nuclear force is the interaction between quarks, then I should explain what a quark is, what kind of quarks nucleons are made of, and also its responsibility to hold quarks together to form other hadrons]

Do you really suggest me to get that technical about it?

Well, we are not here to tell you or suggest to you how to do your presentation, that's your prerogative. We are here only to answer physics questions. The fact is that the strong force is a force between quarks (and is due to the exchange of gluons) . It holds the quarks inside nucleons together. It is also the force responsible for holding nucleons together in nuclei. In that case, one can approximate the force as the exchange of mesons, but this is an approximation of the underlying process which is still a force between quarks (in physics we often approximate fundamental forces by simpler pictures when working at different energy or distance scales).

If the statement about binding energy bothers you and you want to present something introductory, then just do not mention binding energy at all (which is a fairly difficult concept to start with).

 

[A M]

Well, we are not here to tell you or suggest to you how to do your presentation, that's your prerogative. We are here only to answer physics questions.

If the statement about binding energy bothers you and you want to present something introductory, then just do not mention binding energy at all (which is a fairly difficult concept to start with).

Well, that's my prerogative! Suggesting not to mention something is a suggestion itself!
(I know, I'm a bit stubborn; but the whole my article is based on the definition of binding energy, so I'd rather use that approximation as you said. Thanks for your suggestion -or anything else you call it!)

The fact is that the strong force is a force between quarks (and is due to the exchange of gluons) . It holds the quarks inside nucleons together. It is also the force responsible for holding nucleons together in nuclei. In that case, one can approximate the force as the exchange of mesons, but this is an approximation of the underlying process which is still a force between quarks (in physics we often approximate fundamental forces by simpler pictures when working at different energy or distance scales).

Thanks! this part of your reply (answer to physics question!) helped me improve my article. As you said, I can approximate this force as the exchange of mesons, to avoid confusion.

(By this approximation, it would be easier to explain binding energy and the balance of forces. Anyway, thanks for your correction! )

 

[PeterDonis]

(The interaction between the quarks of a single nucleon isn't called the strong nuclear force.)

Yes, it is. It's not the only name used for that interaction, but it is certainly one of them. Some examples:

http://aether.lbl.gov/elements/stellar/strong/strong.html
https://energyeducation.ca/encyclopedia/Strong_nuclear_force

 

[PeterDonis]

Strong force is a force between quarks

more precisely it is the force between the quarks of TWO nucleons

It's more complicated than either of these.

In a single nucleon, the strong interaction binds the three quarks together. This interaction actually increases in strength with distance; it confines the quarks to within the size of the nucleon, roughly $10^{-15}$ meter.

However, once the three quarks are bound within a single nucleon, when viewed from outside that nucleon, almost all of the quark-quark interaction is cancelled. The strong interaction between nucleons is a residual interaction that is left over. This interaction decreases rapidly with distance, so it only is significant between nearby nucleons.

 

[PeterDonis]

Omg, it's getting worse and worse. if it IS the interaction between the quarks of a single nucleon

The interaction between the quarks of a single nucleon is not the same as the interaction between nucleons. They do both originate from the strong interaction, but at the level you are presenting this material, they are best viewed as different interactions with different behavior. See my post #10 just now.

Also, statements like "omg, it's getting worse and worse" are highly inappropriate. You are asking for help and people are doing their best to provide it. You have admitted that you are a beginner in this subject. Your understanding of the subject is clearly very basic and highly incomplete. That in itself is fine, because you're a beginner; but it means you should not presume to tell other people that their contributions are "getting worse and worse". Especially when you are mistaken yourself.

 

[PeterDonis]

I can approximate this force as the exchange of mesons, to avoid confusion.

If you're not going to talk about quarks and how they make up nucleons, I'm not sure it's necessary to talk about meson exchange either. You can just say there is an interaction between nucleons and briefly describe the properties of the interaction that are important.

 

[A M]

you should not presume to tell other people that their contributions are "getting worse and worse"

By this statement, I just meant that my understanding of this force is in contrast with what has been said, and thus it is getting 'more and more confusing to me'. I did not mean that "their contributions" are getting worse.

I'm not a native or a good English speaker. I sometimes can't express exactly what I mean, I have already admitted that I was mistaken myself, and accepted it, but if some of my words aren't expressed the way I really meant, or they are 'highly inappropriate' [like that "wanna"], or I've bothered you with any of my statements, I am very sorry. I did not really mean to do that.

 

[PeterDonis]

I'm not a native or a good English speaker.

Understood. We'll keep that in mind.

 

[PeterDonis]

Thread closed per OP request.