In a lot of texts $\alpha$ decay is described through a relatively simple quantum tunneling model. An $\alpha$ particle within the attractive strong force potential has some probability of escaping through tunneling, and with this concept you can make interesting theoretical predictions like the Geiger-Nuttall law. But it seems that this model is certainly not a full explanation of the phenomenon. For example, a couple points that can be raised:
How are the alpha particles formed within the nucleus, and how does that alter the decay?
Why don't nuclei decay through other massive particles like a $^3$H nucleus or a $^6$Li nucleus? Why only $^4$He?
Are there more complete models that attempt to explain these kinds of questions and others?
