Wednesday, May 16, 2012

1205.3276 (Ki-Young Choi et al.)

A Dirac right-handed sneutrino dark matter and its signature in the
gamma-ray lines
   [PDF]

Ki-Young Choi, Osamu Seto
We show that a Dirac right-handed scalar neutrino can be weakly interacting massive particle in the neutrinophilic Higgs model. When the additional Higgs fields couple only to the leptonic sector through neutrino Yukawa couplings, the right number of relic density of dark matter can be obtained from thermal freeze-out of the dark matter annihilation into charged leptons and neutrinos. At present, this annihilation is suppressed by the velocity of dark matter. However one-loop annihilation cross section into $\gamma\gamma$ can be larger than that of the helicity suppressed annihilation into fermions, because relevant coupling constants are different. Hence, gamma-ray line signal which might have been observed in the Fermi-LAT is also able to be explained by its annihilation.
View original: http://arxiv.org/abs/1205.3276

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