Current status and prospects of light bino-higgsino dark matter in natural SUSY

Abstract

Given recent advancements in dark matter (DM) search experiments, particularly the latest LUX-ZEPLIN (LZ) direct detection (DD) results, we systematically investigate the light bino-higgsino DM scenario within the natural supersymmetric framework. Requiring the electroweak fine-tuning parameter $Δ_{\text{EW}} < 30$ fixes the higgsino mass parameter in the range $|μ| \in [100, 350]$ GeV, while we extend the bino mass to $M_1 \in [10, 350]$ GeV. Incorporating constraints from Higgs physics, rare $B$ decays, LEP limits, and DD experiments, we find that part of the parameter space remains viable. However, the relic density of neutralino DM necessarily lies below the observed Planck value, contributing at most $\sim 2\%$ of the total DM abundance. Some of the surviving parameter space is already excluded by current 13 TeV LHC searches, while the future 14 TeV HL-LHC with 3000 fb$^{-1}$ luminosity will probe the remaining region.

Figures (2)

• Figure 1: Spin-independent/dependent DM-nucleon cross sections. All samples satisfy the $\chi^2_{tot} < 6$ constraint. Red crosses are excluded by current electroweakino searches at the 13 TeV LHC at 95% C.L., while blue stars are projected to be searched at the 14 TeV HL-LHC with luminosity of 3000 fb$^{-1}$. Red solid lines are 90% C.L. upper limits from LZ (2015) experiments LZ:2024zvo. Black dashed line is the neutrino floor. $f$ represent the ratio of the predicted DM relic density to the value observed by Planck.
• Figure 2: Same as Fig. \ref{['fig:DD']}, but shown in the $\mu$ vs. $M_1$ plane (left panel) and the $f$ vs. $m_{\tilde{\chi}_1^0}$ plane (right panel). Here, $f$ denotes the ratio of the predicted dark matter relic density to the value observed by Planck.