Re: What is the equation for calculating the strong force between two particles

I've used Perkins, Introduction to High Energy Physics, pages 20-21.

In the text, he writes the potential between two quarks to be of the form

V = -(4alpha_s)/(3r) + kr

where alpha_s is the strong coupling constant, or the strength of the
strong force, r is the distance between them, and k is a constant
determined experimentally. 

The first term is from single gluon exchange and the second is from
confinement at large r. What's confinement? It means that if we pull two
quarks far enough apart, the force between them becomes infinite. What
happens? A quark/anti-quark pair is pulled from the vacuum, using the
energy stored in kr. 

This is, I think, more technical than you wanted. Unfortunately, the strong
force is pretty complicated (for example, alpha_s is not a constant but
depends on the energy of the quarks and gets larger for large distances)
and this is only an approximation....