Although scientists believe dark matter is made of either axions - a class of extremely light particles whose existence is predicted by an extension of quantum chromodynamics - or Weakly Interacting Massive Particles, which are heavy particles that interact with normal matter only through gravity and the weak nuclear force
, no such particles have yet been detected.
WIMPs are thought to interact with normal matter only via the weak nuclear force
The three quantum-based forces are electromagnetism, the weak nuclear force
(responsible for radioactivity) and the strong nuclear force (which glues together the protons and neutrons in atomic nuclei).
In particular, without supersymmetry, it's very difficult to understand why the weak nuclear force
is a whopping [10.
The four forces of nature are considered to be the gravitational force, the electromagnetic force, which has residual effects, the weak nuclear force
, and the strong nuclear force, which also has residual effects.
However, scientists have demonstrated that the phenomenon of radioactivity is due to an additional force in nature, called the weak nuclear force
, and also to an additional fundamental particle, called the neutrino.
It is held together, indeed balanced exquisitely, by the four fundamental forces: gravity, electromagnetism and the strong and weak nuclear force
Currently, the hypothetical Weakly Interacting Massive Particles, which are believed to interact with normal matter through gravity and the weak nuclear force
, are the leading candidates to explain the composition of dark matter, but what class of particles these WIMPs belong to is not yet known.
Neutrinos, electrically neutral particles that sense only gravity and the weak nuclear force
, interact so feebly with matter that over 100 trillion zip unimpeded through your body every second.
Because the surviving WIMPs interact with familiar matter only through the weak nuclear force
and gravity, nature's two weakest forces, these particles are exceedingly difficult to detect.
The latest discovery involves the weak nuclear force
and is harder to identify experimentally.
These particles, on the rare occasions they interact with surrounding matter, do so via weak nuclear force