Why in a Nuclear reaction we have Alpha particles and not Hydrogen nucleus?

Question

I mean Alpha are He nucleus (Atomic mass=4)
Why are not emitted simplier particles, like for example H nucleus (Atomic mass=1) emitted?

Answer 1

It's a quantum tunneling process governed by the strong nuclear force. If I have a pile of rocks, it's much easier for me to pick up a rock than to pick up half a rock. To get half a rock, I'd need to pull the rock apart.