# The strong force and E=mc2

1. Feb 13, 2010

### briansacks

I have read that the strength of the strong interaction between two quarks is roughly the same as the weight of a 10 tonne truck (i.e. 105 N).

There is a relationship between Force and distance and work and energy and mass (and I am aware of the extent to which Newtonian mechanics is perturbed by special relativity in all this), and it seems to me, looking at the sums, that my introductory sentence above may just be the logical/mathematical restatement of ‘E=mc2’.

However, E=mc2 – and the whole of special relativity in fact - seems to me to just be a brilliant restatement of the statement “the speed of light is a constant” (or “there is no such thing as the ether”).

An (admittedly not comprehensive) Internet search seems to indicate that much of the information about the strong force is inferred theoretically rather than directly measured. Is our whole theory about the strong force and its magnitude resting just on the foundations of Maxwell and Michelson and Morley, and their findings about the significance, and invariance, of the speed of light?

2. Feb 13, 2010

### ansgar

very much is known experimentally about the strong force

3. Feb 13, 2010

### Naty1

Sorry to disappoint, but I'd disagree with each of your comments above.

No.

No. but the relationship does flow from relatvititic theory of which light is a key part.

Maybe to the first part; I seem to recall reading quarks have not been observed in isolation due to the huge attractive force between them..but I do not know exactly what has been experimentally measured....

but No to the second. We get a lot of "information" from measurement and theory combined, much less from either in isolation without the other. The electromagnetic force falls off with distance, not so the sterong force.
////////////
Wikipedia says :

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

and in any event derives from quantum chromodynaics (QCD) and theWeinberg-Salaam model...

If anything relativity is not about forces but about geometry. The standard model incorporates some aspects of relativity, but in fact the heart of relativity, gravity, remains outside the standard model of particle physics....

There are some great threads here on the standard model and the mathematical aspects of it that have been "unified", at least loosly speaking. You can get an idea of how strong,weak,and electromagnetic forces are related from the unifying mathematical theory....

4. Feb 13, 2010

### humanino

You need to convert 1 GeV per fermi in a force in to get about 16 tons (160 kN). This is the "string tension" one gets out of Regge theory. So yes, roughly you need to attach the weight of two horses to pull out a quark from a hadron. That's pretty amazing.

More recent formalism suggest possibly 50 times weaker forces in the transverse direction
http://arxiv.org/abs/0810.3589