Dark matter signals and cosmic ray anomalies in an extended seesaw model

Abstract

An extended seesaw model proposed to achieve low scale leptogenesis can resolve the excess positron and electron fluxes observed from PAMELA, ATIC and/or Fermi-LAT, and simultaneously accommodate some of recent experimental results for dark matter (DM) signals. In this approach, in addition to SU(2)_L doublet and the (light) singlet Higgs fields, an extra vector-like singlet neutrino and a singlet scalar field, which are coexisting two-particle dark matter candidates, are responsible for the origin of the excess positron and electron fluxes to resolve the PAMELA, ATIC and/or Fermi-LAT anomalies, as well as for the DM signals observed from direct searches in low mass scale.

Comments: title changed slightly, some mistakes are corrected, recent results of dark matter with low mass are included and some numerical results are imporved