As mentioned above, WIMPs are a form of CDM with masses around 45 GeV. WIMPs are the most probable dark matter candidate because they are CDM and they only interact with themselves through the weak force and through gravity.
One of the most interesting things about WIMPs is that they could be their own anti-matter. In other words, when a WIMP and another WIMP come into contact, one of the WIMPs acts like the anti-WIMP and they annihilate each other. There is also the possibility that there are anti-WIMPs, but many physicists favor the model where WIMPs annihilate other WIMPs. This means, that in the early Universe when all of the WIMPs were formed, they would annihilate each other constantly. Through annihilation, they produce ordinary matter such as neutrinos, gamma rays, electrons, and positrons. Their neutrinos and gamma rays have special signatures that when analyzed could prove the presence of WIMPs. This idea is discussed more in a later section - indirect detection. (4, 5, 6)
In the early Universe a WIMP could not travel very far without running into and annihilating another WIMP. But, as the Universe expanded, the annihilation events slowed and the Universe reached a stable equilibrium of WIMPs that virtually never ran into another WIMP. This is called the “WIMP miracle” because just the right amount of WIMPs would have been able to survive to produce the amount of dark matter needed. (4, 5)
Figure 6 shows how a WIMP and the anti-WIMP pair would annihilate to produce ordinary matter.