Well if the distance between the particles equals 0, then the electric field equals infinity as well as the magnetic field (since E is dependent of r and magnetic field is dependent on E).
I remember reading somewhere that the weak force becomes greater than the electromagnetic force for distances less than 10^-18 m so what I was thinking is if the particles could be smashed together that close, then the weak force would take over and contact the particles together, like gravity does to the particles in a singularity.