Most fermions will decay by a weak interaction over time.
The weak interaction has a very short range (around 10-10 m).
The theory of weak interactions has been tested and found correct to a few parts in a thousand.
Since this is due to weak interactions it is very small, 10 times the mass of each state.
According to this theory, there was not much difference between weak, strong and electromagnetic interactions in the very early universe.
A distinctly different process is the production of single tops via weak interaction.
The strength of the weak interaction is an outstanding problem in modern particle physics.
They are often studied to gain knowledge on the weak interaction.
However, the parity violation of weak interaction was discovered instead.
Natural radioactivity is also an expression of the weak interaction.