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 $Δ_{\mathrm{EW}} < 30$ fixes the higgsino mass parameter in the range of $|μ| \in [100, 350]$~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$2\% of the total DM abundance. Some of the surviving parameter space is already excluded by current 1\mbox{3 TeV LHC sear}ches, while the future 14 TeV HL-LHC with 3000 fb$^{-1}$ luminosity will probe the remaining region of the considered parameter space.