More ideas from E
Diagram showing that beta decay has a preferred direction. It is chiral, and so cannot be superimposed on its mirror image. It cannot be superimposed on its mirror image once it has been turned upside down, and so is not symmetrical under parity transformations.

The weak nuclear force is the second weakest force, after gravity, and it is the force with the shortest range. It was first devised to explain beta decay.