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Combined collider constraints on neutralinos and charginos

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
Source :
Eur.Phys.J. C79 (2019) no.5, 395
Publication Year :
2018

Abstract

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.<br />Comment: 38 pages, 16 figures, v3 is the version accepted by EPJC

Details

Database :
arXiv
Journal :
Eur.Phys.J. C79 (2019) no.5, 395
Publication Type :
Report
Accession number :
edsarx.1809.02097
Document Type :
Working Paper
Full Text :
https://doi.org/10.1140/epjc/s10052-019-6837-x