Mixed neutralino dark matter in nonuniversal gaugino mass models

Abstract

We have considered nonuniversal gaugino mass models of supergravity, arising from a mixture of two superfield contributions to the gauge kinetic term, belonging to a singlet and a nonsinglet representation of the grand unified theory group. In particular we analyze two models, where the contributing superfields belong to the singlet and the 75-dimensional, and the singlet and the 200-dimensional representations of $SU(5)$. The resulting lightest superparticle is a mixed bino-Higgsino state in the first case and a mixed bino-wino-Higgsino state in the second. In both cases one obtains cosmologically compatible dark matter relic density over broad regions of the parameter space. We predict promising signals in direct dark matter detection experiments as well as in indirect detection experiments via high energy neutrinos coming from their pair annihilation in the Sun. Besides, we find interesting $\ensuremath{\gamma}$-ray signal rates that will be probed in the Fermi gamma-ray space telescope. We also expect promising collider signals at LHC in both cases.