Light Dark Matter from the U(1)_X Sector in the NMSSM with Gauge Mediation

TL;DR

This paper proposes a supersymmetric model with a light U(1)_X sector that explains both cosmic ray anomalies and direct detection signals through different dark matter mass scales, without introducing new arbitrary scales.

Contribution

It introduces a gauge mediated NMSSM extended with a light U(1)_X sector and a heavy sector, naturally generating both light and heavy dark matter candidates.

Findings

Light dark matter (~7 GeV) can explain CoGeNT and DAMA/LIBRA results.

Heavy (TeV-scale) dark matter explains cosmic ray anomalies.

The model predicts a small kinetic mixing parameter (~10^{-5}-10^{-6}).

Abstract

Cosmic ray anomalies observed by PAMELA and Fermi-LAT experiments may be interpreted by heavy (TeV-scale) dark matter annihilation enhanced by Sommerfeld effects mediated by a very light (sub-GeV) U(1)_X gauge boson, while the recent direct searches from CoGeNT and DAMA/LIBRA experiments may indicate a rather light (\sim 7 GeV) dark matter with weak interaction. Motivated by these apparently different scales, we consider a gauge mediated next-to-the minimal supersymmetric standard model (NMSSM) entended with a light U(1)_X sector plus a heavy sector (\bar H_h,H_h), which can provide both a light (\sim 7 GeV) and a heavy (TeV-scale) dark matter without introducing any ad hoc new scale. Through the Yukawa coupling between H_h and the messager fields, the U(1)_X gauge symmetry is broken around the GeV scale radiatively and a large negative m_S^2 is generated for the NMSSM singlet S. Furthermore, the small kinetic mixing parameter between U(1)_X and U(1)_Y is predicted to be \theta\sim 10^{-5}-10^{-6} after integrating out the messengers. Such a light dark matter, which can have a normal relic density from the late decay of the right-handed sneutrino (assumed to be the ordinary next-to-the lightest supersymmetric particle and thermally produced in the early universe), can serve a good candidate to explain the recent CoGeNT and DAMA/LIBRA results.