Strong nuclear force

Hi people. Its been a very long time since ive been to ATS. It seems like a lot has changed.

Could anyone help me find equations that describe the strong nuclear force ? And could someone tell me briefly how the strong nuclear force holding quarks together in a proton and neutron operates i.e the nature of the force

[edit on 6-3-2007 by siddharthsma]

[edit on 6-3-2007 by siddharthsma]

Infact, tell me evrything you know about the strong nuclear force

An interesting topic for this forum

Here's a backgrounder on the fundamentals of the Strong Nuclear Force;

The Strong Nuclear Force (also referred to as the strong force) is one of the four basic forces in nature (the others being gravity, the electromagnetic force, and the weak nuclear force). As its name implies, it is the strongest of the four. However, it also has the shortest range, meaning that particles must be extremely close before its effects are felt. Its main job is to hold together the subatomic particles of the nucleus (protons, which carry a positive charge, and neutrons, which carry no charge. These particles are collectively called nucleons). As most people learn in their science education, like charges repel (+ +, or - -), and unlike charges attract (+ -).



If you consider that the nucleus of all atoms except hydrogen contain more than one proton, and each proton carries a positive charge, then why would the nuclei of these atoms stay together? The protons must feel a repulsive force from the other neighboring protons. This is where the strong nuclear force comes in. The strong nuclear force is created between nucleons by the exchange of particles called mesons. This exchange can be likened to constantly hitting a ping-pong ball or a tennis ball back and forth between two people. As long as this meson exchange can happen, the strong force is able to hold the participating nucleons together. The nucleons must be extremely close together in order for this exchange to happen. The distance required is about the diameter of a proton or a neutron. If a proton or neutron can get closer than this distance to another nucleon, the exchange of mesons can occur, and the particles will stick to each other. If they can't get that close, the strong force is too weak to make them stick together, and other competing forces (usually the electromagnetic force) can influence the particles to move apart. This is represented in the following graphic. The dotted line surrounding the nucleon being approached represents any electrostatic repulsion that might be present due to the charges of the nucleons/particles that are involved. A particle must be able to cross this barrier in order for the strong force to "glue" the particles together.




LINK

If it wasn't for the Strong Nuclear Force, I suspect all matter would disintegrate. Here's some related reading;

Link 1

Link 2

Link 3

I'm looking forward to the discussion that this subject provokes.

Yea it's simple. Just use macro model (change freequency) of solar system and frequency of sun. Create fision and extract energy.

I also got cold fusion system.

Hey sidd,

Having taken a course in Subatomic Physics, I can tell you that the strong nuclear force is carried out by virtual pions. The derivation is quite lengthy, and to be honest you need a solid background in mathematics to understand how the pion was originally thought about. If you would like me to do so, you'll have to give me some time. Just say the word.

However, I can explain something that you may already know, and that is virtual particles basically have to carry some forces. If not for virtual particles, the idea would disobey all laws of physics. But one uncertaintly relation is delE*delT = h-bar, and given a short amount of time, energy conservation can be violated, which is what happens in the strong nuclear force. So, obviously, this explains why the strong nuclear force must be a short ranged and short lived force - otherwise our view of the nucleus wouldn't make sense.

Anything else I may be able to elaborate on?

[edit on 6-3-2007 by T_Jesus]

Hello,
The idea of pion exchange was the original theory for the strong nuclear force, but I am under the impression this was superceded by quantum chromo dynamics (QCD) with quarks (fermion particles), gluons (the force carrying bosons) and colour charge. Gravity has one "charge": mass, Electromagnetism has two + and -, the colour force has three charges red, green and blue. Stable particles are formed in threes (baryons) when 3 quarks have all three charges. Stable particle pairs are formed for 2 particles (mesons) when one quark has a colour, say red and the other has the corresponding anti-colour, (anti-red). Each gluon is supposed to carry a colour charge and an anti-colour charge simultaneously (8 possibilities in total I think). Beacause gluons are themselves chaged they can interact with each other to form glueballs, (unlike photons and gravitons). There you go!

Dr X information is the most recent that I've read.

QCD describes the new "Strong Force".

The Residual Strong force or "nuclear force" still describes the short range interactions of the nucleus.

And since we've never actually 'seen' a quark I find the SM and QCD to be a bit questionable. The more you look at experimental data the more it seems the SM jumps through hoops to stay 'standard'.

If there are aliens that is the one subject I'd like to get an answer to!

Abandon, quarks have been seen. Electron scattering experiments show three equidistant point particles from scattering off a neutron I think. What I think you mean is that no lone quark has ever been isolated. this is because the strong force gets stronger the further you pull on a pair of quarks, eventually a quark and antiquark will form from out of the vacuum like this:

A-Q A----Q A-Q A-Q

(quark and anti-quark meson)

Giving a new meson.

Thanks alot Masqua. Ive had a very quick look at your links and Ive already found something very useful to me !


[Quote]
Basic properties of the nuclear force
The nuclear force is only felt among hadrons.
At typical nucleon separation (1.3 fm) it is a very strong attractive force (104 newtons).
At much smaller separations between nucleons the force is very powerfully repulsive, which keeps the nucleons at a certain average separation.
Beyond about 1.3 fm separation, the force exponentially dies off to zero.
At short distances, the nuclear force is stronger than the Coulomb force; it can overcome the Coulomb repulsion of protons inside the nucleus. However, the Coulomb force between protons has a much larger range and becomes the only significant force between protons when their separation exceeds about 2.5 fm.
The NN force is nearly independent of whether the nucleons are neutrons or protons. This property is called charge independence.
The NN force depends on whether the spins of the nucleons are parallel or antiparallel.
The NN force has a noncentral or tensor component. This part of the force does not conserve orbital angular momentum, which is a constant of motion under central forces.
[Quote/]

Now, I can see that one of the properties says it becomes very strongly repulsive at extremely short distances, anyone know why this happens ?

Originally posted by Dr X
... quarks have been seen. Electron scattering experiments show three equidistant point particles from scattering off a neutron....

Oh? I'd love to see a link on that if you have one!

I'm familiar with the general theory of electron scattering and it makes sense when applied to the nucleus. However the 'quark confinment model' seems like hogwash. "It is postutated that it may actually increase with distance at the rate of about 1 GeV per fermi." Nothing else in the universe behaves like that! Universally the greater the distance the less the force. It reminds me so much of the "psychic" who says..."oh, I can't tell you the future, even thought I see it, because the spirits prevent me"

Now when the LHC comes on line this year I might be eating a big helping of crow pie!

I also have issues with the fact that Quarks are considered elementary particles yet in different mesons the same two can have different mass. Again the rest of the universe doesn't work that way.

I'm really looking forward to the LHC!

Please, folks, do post links! Inquiring minds want to know where to read more on the subject!

Re: quark observation

The only online info I could find is here:

en.wikipedia.org...

I found this out from my undergraduate text book:

Nuclear and particle physics by W. S. C> Williams.

www.amazon.co.uk...

Sory is there any practial use of this knowledge? or its just for school.