Abstract
Results are presented from a search for the direct electroweak production of charginos and neutralinos in signatures with either two or more leptons (electrons or muons) of the same electric charge, or with three or more leptons, which can include up to two hadronically decaying tau leptons. The results are based on a sample of proton-proton collision data collected at sqrt{s}=13 TeV, recorded with the CMS detector at the LHC, corresponding to an integrated luminosity of 35.9 fb−1. The observed event yields are consistent with the expectations based on the standard model. The results are interpreted in simplified models of supersymmetry describing various scenarios for the production and decay of charginos and neutralinos. Depending on the model parameters chosen, mass values between 180 GeV and 1150 GeV are excluded at 95% CL. These results significantly extend the parameter space probed for these particles in searches at the LHC. In addition, results are presented in a form suitable for alternative theoretical interpretations.
Highlights
In the case of conserved R-parity [12], SUSY particles are created in pairs, and the lightest SUSY particle (LSP) is stable, making it a possible dark matter candidate
This paper describes a search for direct production of charginos and neutralinos, mixtures of the SUSY partners of the electroweak gauge and Higgs bosons, decaying to two, three, or more charged leptons, and significant missing transverse momentum
After applying a threshold pT > 40 GeV on the photon to suppress the contribution of Wγ events produced by final-state radiation (FSR) which influences MT, we find the W boson MT distribution shapes in simulated Wγ, W+jets, and WZ processes to be the same
Summary
This search targets scenarios of direct electroweak production of charginos χ±1 and neutralinos χ02, which decay into final states containing two, three, or four charged leptons (e±, μ±, τ ±). Χ±1 χ02 production with L-mediated decays: the chargino and neutralino decay via sleptons or sneutrinos to all lepton flavors with the same branching fraction (“flavordemocratic” scenario). The neutralino still decays to all three flavors In this model, both left-handed sleptons and sneutrinos are considered to be heavy and decoupled; they do not participate in this process. As for the pair of neutralinos (χ02χ02 or χ01χ01) the production cross section is vanishingly small [27,28,29], we consider a specific gauge-mediated SUSY breaking (GMSB) model with four higgsinos (χ02, χ±1 , χ01) and an effectively massless gravitino G as the LSP [30,31,32]. Different final states depending on the assumptions on the NLSP are possible, as shown in figure 3
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