Probing bino-wino coannihilation dark matter under the neutrino floor at the LHC

TL;DR

This paper explores the potential of the LHC to detect bino-wino coannihilation dark matter scenarios, which are difficult to test via direct detection due to their low scattering cross sections, by analyzing soft dilepton events.

Contribution

It proposes a novel search strategy at the LHC for bino-wino coannihilation dark matter, extending the mass reach beyond current direct detection capabilities.

Findings

Wino-like $ ext{chi}_2^0$ mass can be probed up to 310 GeV at 2σ with 300 fb$^{-1}$

Mass limits can be increased to 430 GeV at HL-LHC with 3000 fb$^{-1}$

The method provides a viable way to test otherwise inaccessible dark matter scenarios.

Abstract

In the minimal supersymmetric standard model (MSSM) the bino-wino coannihilation provides a feasible way to accommodate the observed cosmological dark matter (DM) relic density. However, such a scenario usually predicts a very small DM-nucleon scattering cross section that is below the neutrino floor, and can not be tested by DM direct detection experiments. In this work, we investigate the discovery potential of this bino-wino co-annihilation region by searching for the soft dilepton events from the process $pp \to \chi^0_2 (\to \ell^+\ell^- \chi^0_1) \chi^\pm_1+jets$ at the LHC. We find that the mass of the wino-like $\chi^0_2$ can be probed up to about 310 (230) GeV at $2\sigma$ ($5\sigma$) level for an integrated luminosity ${\cal L}=300$ fb$^{-1}$. In the future HL-LHC with 3000 fb$^{-1}$ luminosity, the corresponding mass limits can be pushed up to 430 (330) GeV.