Asymmetric Dark Matter from a GeV Hidden Sector

TL;DR

This work presents a supersymmetric Asymmetric Dark Matter framework in which a GeV-scale DM mass is generated by one-loop gauge kinetic mixing between the SM hypercharge and a GeV-scale dark U(1). An asymmetric transfer operator links the baryon asymmetry to the dark sector, while a GeV dark photon enables efficient annihilation of the symmetric DM component, preserving the DM abundance as set by the baryon asymmetry. The model naturally integrates with gauge mediation, yields a loop-suppressed direct-detection cross section in the $10^{-42}$ cm^2 range for 1–15 GeV DM, and offers rich cosmological histories depending on the chosen asymmetry-transfer operator. It also presents concrete collider and astrophysical signatures, including lepton-jet–like events and specific constraints from BBN, CMB, and current/future direct-detection experiments.

Abstract

Asymmetric Dark Matter (ADM) models relate the dark matter density to the baryon asymmetry, so that a natural mass scale for ADM is around a few GeV. In existing models of ADM, this mass scale is unexplained; here we generate this GeV scale for dark matter (DM) from the weak scale via gauge kinetic mixing with a new Abelian dark force. In addition, this dark sector provides an efficient mechanism for suppressing the symmetric abundance of DM through annihilations to the dark photon. We augment this sector with a higher dimensional operator responsible for communicating the baryon asymmetry to the dark sector. Our framework also provides DM candidate for gauge mediation models. It results in a direct detection cross section of interest for current experiments: sigma less than or similar to 10^{-42} cm^2 for DM masses in the range 1 - 15 GeV.

Figures (4)

• Figure 1: The spectrum of the SUSY model. We have illustrated the mass pattern of the $S/T$ multiplet (not to scale) since this splitting determines the identity of the DM. The splittings within the dark photon multiplet have been suppressed.
• Figure 2: Constraints in the $\epsilon-g_d$ plane. We have shown the regions which are excluded by BBN constraints due to $\tilde{\gamma}_d\rightarrow \gamma \tilde{G}$Jedamzik:2006xz (orange), $B$-factories due to direct searches for $\gamma_d$Essig:2010ye (green), and precision electroweak measurements due to $\gamma_d-Z^0$ mixing Gopalakrishna:2008dv (brown). The red region corresponds to parameters which solve the lithium-7 problem Jedamzik:2006xz. One the left (right) we show contours where $\lambda$ is constrained so as not to reach Landau pole before $M_\mathrm{GUT}$ (10 TeV) for $m_\mathrm{DM} = 14.2\hbox{GeV}$, $m_\mathrm{DM} = 7.1\hbox{GeV}$ and $m_\mathrm{DM} = 3.3\hbox{GeV}$, assuming $\langle D_Y \rangle = 72$ GeV. The region below these contours is excluded.
• Figure 3: The one-loop diagram which generates the $S$ number violating mass $b_S$.
• Figure 4: The predictions for the direct detection scattering cross sections normalized per proton ($\sigma_p$) for $m_\mathrm{DM} = 14.2 \hbox{GeV}$, 7.1 GeV and 3.3 GeV. We have plotted current/projected limits (also normalized per proton) from Xenon-10 (solid black line), Xenon-100 with 6,000 kg-days (dashed green line), Xenon-1T (dotted blue line) DMPlotter, and Majorana (dot-dashed purple line) MAJORANA.