Combined collider constraints on neutralinos and charginos

• Published in: The European physical journal. C, Particles and fields Vol. 79; no. 5; pp. 1 - 52
• Main Authors: Athron, Peter, Balázs, Csaba, Buckley, Andy, Cornell, Jonathan M., Danninger, Matthias, Farmer, Ben, Fowlie, Andrew, Gonzalo, Tomás E., Harz, Julia, Jackson, Paul, Kudzman-Blais, Rose, Kvellestad, Anders, Martinez, Gregory D., Petridis, Andreas, Raklev, Are, Rogan, Christopher, Scott, Pat, Sharma, Abhishek, White, Martin, Zhang, Yang
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.05.2019; Springer; Springer Nature B.V; Springer Verlag (Germany); SpringerOpen
• Subjects: Analysis; Astronomy; Astrophysics and Cosmology; Bosons; Confidence intervals; Dark matter; Density; Elementary Particles; Fermions; Hadrons; Heavy Ions; Higgs bosons; High Energy Physics - Phenomenology; Large Hadron Collider; Luminosity; Measurement Science and Instrumentation; Nuclear Energy; Nuclear Physics; Particle accelerators; Particle collisions; Physics; Physics and Astronomy; Protons; Quantum Field Theories; Quantum Field Theory; Regular Article - Experimental Physics; Searching; Solenoids; String Theory; Supersymmetry; supersymmetry; neutralino: production; CERN LHC Coll; chargino: production; neutralino: mass; new physics: search for; Higgs particle: invisible decay; dark matter: relic density; minimal supersymmetric standard model; p p: scattering; chargino: mass; neutralino: dark matter; Z0: invisible decay
• ISSN: 1434-6044; 1434-6052
• DOI: 10.1140/epjc/s10052-019-6837-x

Searches for supersymmetric electroweakinos have entered a crucial phase, as the integrated luminosity of the Large Hadron Collider is now high enough to compensate for their weak production cross-sections. Working in a framework where the neutralinos and charginos are the only light sparticles in the Minimal Supersymmetric Standard Model, we use GAMBIT to perform a detailed likelihood analysis of the electroweakino sector. We focus on the impacts of recent ATLAS and CMS searches with of 13 TeV proton-proton collision data. We also include constraints from LEP and invisible decays of the Z and Higgs bosons. Under the background-only hypothesis, we show that current LHC searches do not robustly exclude any range of neutralino or chargino masses. However, a pattern of excesses in several LHC analyses points towards a possible signal, with neutralino masses of = (8–155, 103–260, 130–473, 219–502) GeV and chargino masses of = (104–259, 224–507) GeV at the 95% confidence level. The lightest neutralino is mostly bino, with a possible modest Higgsino or wino component. We find that this excess has a combined local significance of 3.3 σ , subject to a number of cautions. If one includes LHC searches for charginos and neutralinos conducted with 8 TeV proton-proton collision data, the local significance is lowered to 2.9 σ . We briefly consider the implications for dark matter, finding that the correct relic density can be obtained through the Higgs-funnel and Z -funnel mechanisms, even assuming that all other sparticles are decoupled. All samples, GAMBIT input files and best-fit models from this study are available on Zenodo.