Supersymmetric dark matter

The standard model of particle physics excellently describes all known fundamental particles and forces (with the exception of gravity). Over the last several decades, this theory has become established through a preponderance of experimental data, culminating in the detection of the top quark at the Tevatron collider. However, while there has never been a direct observation of a particle that does not fit in the standard model, there are compelling reasons to believe that such particles exist, and so the standard model is not a complete description of Nature.