Originally Posted by Celestial Mechanic

Protons do not "grow". They have three quarks, two of them up quarks and one of them down, and the spins and isospins add up to give them a spin of 1/2 and an isospin of +1/2. All of this has been measured in numerous experiments. In these experiments no proton ever grows from anything, it is either one of the incoming particles, or if it is the result of a collision it is created outright, fully intact with all of the properties that we measure for it.

Can you point to any experiments that show this supposed "growth" of protons?