Pseudo-Dirac Bino Dark Matter

TL;DR

This paper proposes a pseudo-Dirac bino as a novel dark matter candidate in supersymmetric theories, addressing annihilation suppression issues and evading direct detection constraints.

Contribution

It introduces the pseudo-Dirac bino arising from D-type SUSY-breaking, providing a natural co-annihilation mechanism and compatibility with detection limits.

Findings

Enhanced co-annihilation due to degeneracy of states

Compatibility with WMAP and direct detection constraints

Addresses p-wave suppression in MSSM bino

Abstract

While the bino-dominated lightest neutralino of the minimal supersymmetric Standard Model (MSSM) is an interesting and widely-studied candidate of the dark matter, the p-wave suppression of its annihilation cross section requires fine-tunings of the MSSM spectra to be consistent with WMAP observations. We propose pseudo-Dirac bino that arises in theories with D-type supersymmetry-breaking as an intriguing alternative candidate of dark matter. The pseudo-Dirac nature of the bino gives a natural mechanism of enhanced co-annihilation because these two states are degenerate in the absence of electroweak symmetry breaking. In addition, the lightest state can be consistent with limits of direct detection experiments because of the lack of vector interactions, as with the case of the MSSM bino.