Combined collider constraints on neutralinos and charginos

• Published in: arXiv.org
• Main Authors: The GAMBIT Collaboration, 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: Paper Journal Article
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 20.06.2019
• Subjects: Bosons; Confidence intervals; Dark matter; Fermions; Higgs bosons; Large Hadron Collider; Luminosity; Particle collisions; Physics - Cosmology and Nongalactic Astrophysics; Physics - High Energy Physics - Phenomenology; Searching; Solenoids; Supersymmetry
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.1809.02097

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 36 fb\(^{-1}\) 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 \((m_{\tilde{\chi}_1^0}, m_{\tilde{\chi}_2^0}, m_{\tilde{\chi}_3^0}, m_{\tilde{\chi}_4^0})\) = (8-155, 103-260, 130-473, 219-502) GeV and chargino masses of \((m_{\tilde{\chi}_1^{\pm}}, m_{\tilde{\chi}_2^{\pm}})\) = (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 \(3.3\sigma\), 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\(\sigma\). 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.