Monday, April 30, 2012
High Energy Physics Seminar
Warm Dark Matter and Low Scale Left-Right Symmetry?
Yue Zhang, ICTP, Trieste
We investigate the viability of having a dark matter candidate in the minimal left-right symmetric theory. We find the lightest right-handed neutrino with a mass around keV as the only viable candidate, consistent with a TeV scale of left-right symmetry. For such low scales, in order to account for the correct relic density, the thermal overproduction of such dark matter in the early universe is compensated by a sufficient late entropy production due to late decay of heavier right-handed neutrinos. We point out that the presence of new charge-current interactions, operative around the QCD phase transition, has a crucial impact on the amount of dilution, as does the nature of this phase transition. A careful numerical study employing the Boltzmann equations reveals the existence of a narrow window for the right-handed gauge boson mass, possibly within the reach of LHC. We also elaborate on a variety of astrophysical, cosmological and low energy constraints on this scenario.