Full Idea
The beta decay of the neutron (into a proton, an electron and an antineutrino) can be described in terms of the weak force, which is 10,000 times weaker than the strong force. It allows the quarks and leptons to change from one type to another.
Gist of Idea
The weak force explains beta decay, and the change of type by quarks and leptons
Source
New Scientist writers (Why the Universe Exists [2017], 02)
A Reaction
This seems to make it the key source of radioactivity. Perhaps it should be called the Force of Change?
Book Reference
New Scientist writers: 'Why the Universe Exists' [John Murray 2017], p.28