Conservation Laws and Invariance Principles

Abstract

There are four types of interactions for elementary particles which sharply differ from one another, the gravitational, the electromagnetic, the strong and the weak. The gravitational interaction which results from the mass of the bodies has a small coupling constant which specifies the strength of interaction. This type of interaction is insignificant in particle physics in ordinary conditions simply because the masses of elementary particles themselves are very small. Thus, the gravitational energy between two protons which are a distance r=2 fm apart, will be $$V(r)= \frac{G m_{p}^{2}}{r} = \frac{6.67\times10^{-11} \times (1.67\times10^{-27} )^{2}}{2\times10^{-15} \times16\times10^{-13}} \simeq6\times10^{-37}~\mbox{MeV} $$ This is much less than the rest mass energy of proton (938 MeV).