LHC constraints on electroweakino dark matter revisited

TL;DR

This paper reanalyzes LHC data to set new bounds on electroweakino dark matter particles, showing that current and future data can exclude winos below 160-200 GeV and higgsinos below 100-130 GeV, respectively.

Contribution

It provides the first LHC limits on nearly mass-degenerate winos and improves constraints on electroweakino masses using a recast of dijet plus MET searches.

Findings

Winos must be heavier than approximately 160 GeV.

Higgsinos must be heavier than approximately 100 GeV.

Future LHC data could extend limits to 200 GeV for winos and 130 GeV for higgsinos.

Abstract

We revisit LHC searches for heavy invisible particles by exploiting QCD initial state radiation. We recast a dijet signal region in a general multijet plus MET search by ATLAS. We find that non-trivial mass limit can be obtained for various models of the electroweakino sector with the present data in hadronic channels. The winos are bound to be heavier than $m_{\tilde W} \gtrsim {160}$ GeV and higgsinos $m_{\tilde h} \gtrsim {100}$ GeV, depending on the chargino-neutralino mass splitting. The expected exclusion limits at the LHC Run 3 with $\mathcal{L} = 300$ fb$^{-1}$ increase to $m_{\tilde W} \gtrsim {200}$ GeV and $m_{\tilde h} \gtrsim {130}$ GeV for winos and higgsino, respectively. This is the first LHC limit for promptly decaying nearly mass-degenerate winos.