What has the LHC told us about the electroweakino sector of the Minimal Supersymmetric Standard Model?

Peter Athron; Csaba Balázs; Andy Buckley; Jon Butterworth; Christopher Chang; Andrew Fowlie; Tomás E. Gonzalo; Vinay Hegde; Ida-Marie Fauske Johansson; Adil Jueid; Tore Klungland; Anders Kvellestad; Farvah Mahmoudi; Gregory D. Martinez; Holly Pacey; Tomasz Procter; Are Raklev; Roberto Ruiz de Austri; Pat Scott; Martin White; Yang Zhang; Pengxuan Zhu

arXiv · 2609.12914

What has the LHC told us about the electroweakino sector of the Minimal Supersymmetric Standard Model?

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Abstract

We perform global fits of the electroweak sector of the Minimal Supersymmetric Standard Model (MSSM) using a comprehensive set of LEP searches, 34 Run 2 LHC searches, and 63 Run 2 LHC measurements. Scanning the bino, wino and Higgsino mass parameters, and the ratio of the Higgs vacuum expectation values, we find that for a light, bino $\tildeχ_{1}^0$, the mass of the next-to-lightest neutralino must be $m_{\tildeχ_{2}^0} \gtrsim 760$ GeV. While MSSM electroweakinos can explain individual excesses observed by ATLAS and CMS in searches targeting compressed spectra, we find no scenarios that fit these excesses simultaneously. When we add a light gravitino, neutralinos are further excluded up to about 1 TeV, though this depends on their composition; Higgsino-dominated $\tildeχ_{1}^0$ requires only $m_{\tildeχ_{1}^0} \approx m_{\tildeχ_{2}^0} \gtrsim 650$ GeV. Lastly, the newer LHC searches and measurements exclude a low-mass region that was preferred in a previous study. This is the most complete summary of collider constraints on the electroweakino sector of the MSSM performed to date.

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Peter Athron, Csaba Balázs, Andy Buckley, Jon Butterworth, Christopher Chang, Andrew Fowlie, Tomás E. Gonzalo, Vinay Hegde, Ida-Marie Fauske Johansson, Adil Jueid, Tore Klungland, Anders Kvellestad, Farvah Mahmoudi, Gregory D. Martinez, Holly Pacey, Tomasz Procter, Are Raklev, Roberto Ruiz de Austri, Pat Scott, Martin White, Yang Zhang, Pengxuan Zhu. 2026-09-11. What has the LHC told us about the electroweakino sector of the Minimal Supersymmetric Standard Model?. https://arxiv.org/abs/2609.12914

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