Mohamad-Ziad Charif - Antares

Figure 2.5: Combination of the WMAP, type Ia supernova, X-ray band, and clustermeasurement for Ω Λ and Ω m .• Hot dark matter, which has relativistic velocities. One candidate for hotdark matter are neutrinos. However, neutrinos are already disfavored asa candidate[21] as their contribution to the matter density is bound to beΩ neutrino < 0.014 much smaller than the expected density of matter in theUniverse. In addition simulations of the large scale structures formation ofthe universe does not favor hot dark matter[26].• Warm dark matter, with the mass being from 300 eV to 3000 eV. However,with extensive searches in colliders (proton and electron) no particle hasever been found in this mass range. Main candidate for warm dark matter isa sterile neutrino.• Cold dark matter, which has non-relativistic velocities (< 1000 km/s) is favoredby simulations of the large scale structures formation of the universe[26].The lower bound mass of cold dark matter is above 1 GeV. The main candidatesfor CDM are the WIMP or Weakly Interacting Massive Particle, andaxions which are theoretical solutions to the strong CP problem in QCD.The most favored model of dark matter is the Weakly Interacting Massive Particle,which we will discuss in the next section.12