Friday, March 22, 2013

1303.5094 (Laura Lopez-Honorez et al.)

Constraints on dark matter annihilation from CMB observations before Planck    [PDF]

Laura Lopez-Honorez, Olga Mena, Sergio Palomares-Ruiz, Aaron C. Vincent
We compute the bounds on the dark matter (DM) annihilation cross section using the most recent Cosmic Microwave Background measurements from WMAP9, SPT and ACT experiments. We consider DM with mass in the MeV-TeV range annihilating 100% into either an e+e- or a mu+mu- pair. We consider a realistic energy deposition model, which includes the dependence on the redshift, DM mass and annihilation channel. We exclude the canonical thermal relic abundance cross section ( = 3 10^(-26) cm3/s) for DM masses below 15 GeV and 30 GeV for the e+e- and mu+mu- channels, respectively. A priori, DM annihilating in halos could also modify the reionization history of the Universe at late times. We implement a realistic halo model taken from results of state-of-the-art N-body simulations and consider a mixed reionization mechanism, consisting on reionization from DM as well as from first stars. We find that the constraints on DM annihilation remain unchanged, even when large uncertainties on the halo model parameters are considered.
View original: http://arxiv.org/abs/1303.5094

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