So I recently heard of a simple way of thinking about how the emission of an alpha particle is "beneficial" to a nucleus being stable. The argument goes as follows: "Let's say we have a nucleus that is unstable because the electric repulsion of protons can't balance out the strong force that tries to keep the nucleus in one piece. Emitting an alpha particle reduces the ratio of protons to neutron in a nucleus so this will make a more stable nucleus. " So, I realize that this is a very simplified version of the story but I know nearly nothing about nuclear physics but this argument seems to be a useful way to rationalize why helium decay makes the nucleus more stable. My question is that, a proton emission is also beneficial to reduce the ratio of protons to neutrons, why is it that nature seems to go with alpha decay instead? I did some googling and had a look at the theory of alpha decay by Gamow; how he deduced it from QM. That's explicatory, but I still think the question is valid, and I couldn't really find anything else on it, possibly I don't know what to search for. As I say I am null with nuclear physics & this sort of advanced physics in general, but I'm curious and would appreciate it if you would point me in the right direction.