Why Quarks Come In Three Colours And Have Fractional Charge
It sometimes happens that my comments in the threads of my own blog get long and detailed (do not take this as me boasting about anything - it is just a fact). When that happens, I reason that they deserve to be promoted to a post by themselves, because threads are read by way fewer readers, and some of them might thus lose some interesting bit.Because of the above I am (re)posting the text below, which explains some "a priori" reasons why quarks come with fractional electric charges in multiples of one third, why the sum of charges of fermions in one family nullify, and why our universe chose to have quarks of three colours. Beware, some non-trivial concepts of quantum field theory are needed, but I will try to make this as painless as possible (but not more). read more