Nothing permanent.
I've seen some people advocate for castration or the death penalty, but may I remind you rape is a very hard crime to convict, which is why it has the lowest conviction rate. Even then, there are many many innocent people convicted of rape, because again, it's so hard to get all the facts right.
The death penalty (as well as castration), should only be reserved for crimines such as serial murder in which there is no shadow of doubt that the defendant commited said henious crime...and serial child rape, I guess etc. stuff along those lines.
Not singular rape cases.