Four Interactions
The universe we know and love exists because the fundamental particles
interact, whether by decaying, annihilating,
or responding to a force due to
the presence of another particle
(for example, during a collision). There are
four interactions between particles:
To clarify things, here are two definitions:
- Force:
- The effect on a particle due to another particle's presence.
-
Interaction:
- The forces and decays which affect a given particle.
An interaction is not the same thing as a force since the word "interaction"
refers to a broader term. Although the terms are often used interchangeably,
physicists prefer the word "interactions."