Theoretical prejudice favors a novel type of particle that interacts only weakly with ordinary matter.
A second intriguing hint of dark matter comes from indirect experiments, which do not look for the elusive particles per se, but for the secondary particles they would produce when they collide with one another and mutually annihilate.
In sum, there is a natural sweet spot for particle dark matter, dubbed the “WIMP miracle.”
Perhaps the dark particle is not even a particle, but an “Unparticle,” as dubbed by one theorist.
Ordinary matter is also composed of many types of particles.
Dark matter could likewise have several contributors, rendering the search more difficult by diluting the putative signature of any specific particle candidate.
These might come from exploring novel types of particles, or we might discover a fully consistent new theory of gravity that dispenses entirely with dark matter.
As they become more sensitive to dark matter, they also become more sensitive to garbage particles, and they cannot always discriminate between the two.
Originally published at Cogly.
