# ${{\widetilde{\boldsymbol \chi}}_{{2}}^{0}}$, ${{\widetilde{\boldsymbol \chi}}_{{3}}^{0}}$, ${{\widetilde{\boldsymbol \chi}}_{{4}}^{0}}$ (Neutralinos) mass limits INSPIRE search

Neutralinos are unknown mixtures of photinos, z-inos, and neutral higgsinos (the supersymmetric partners of photons and of ${{\mathit Z}}$ and Higgs bosons). The limits here apply only to ${{\widetilde{\mathit \chi}}_{{2}}^{0}}$, ${{\widetilde{\mathit \chi}}_{{3}}^{0}}$, and ${{\widetilde{\mathit \chi}}_{{4}}^{0}}$. ${{\widetilde{\mathit \chi}}_{{1}}^{0}}$ is the lightest supersymmetric particle (LSP); see ${{\widetilde{\mathit \chi}}_{{1}}^{0}}$ Mass Limits. It is not possible to quote rigorous mass limits because they are extremely model dependent; i.e. they depend on branching ratios of various ${{\widetilde{\mathit \chi}}^{0}}$ decay modes, on the masses of decay products (${{\widetilde{\mathit e}}}$, ${{\widetilde{\mathit \gamma}}}$, ${{\widetilde{\mathit q}}}$, ${{\widetilde{\mathit g}}}$), and on the ${{\widetilde{\mathit e}}}$ mass exchanged in ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\widetilde{\mathit \chi}}_{{i}}^{0}}{{\widetilde{\mathit \chi}}_{{j}}^{0}}$ . Limits arise either from direct searches, or from the MSSM constraints set on the gaugino and higgsino mass parameters $\mathit M_{2}$ and $\mu$ through searches for lighter charginos and neutralinos. Often limits are given as contour plots in the ${\mathit m}_{{{\widetilde{\mathit \chi}}^{0}}}–{\mathit m}_{{{\widetilde{\mathit e}}}}$ plane vs other parameters. When specific assumptions are made, e.g, the neutralino is a pure photino (${{\widetilde{\mathit \gamma}}}$), pure z-ino (${{\widetilde{\mathit Z}}}$), or pure neutral higgsino (${{\widetilde{\mathit H}}^{0}}$), the neutralinos will be labelled as such.

Limits obtained from ${{\mathit e}^{+}}{{\mathit e}^{-}}$ collisions at energies up to 136 GeV, as well as other limits from different techniques, are now superseded and have not been included in this compilation. They can be found in the 1998 Edition (The European Physical Journal C3 1 (1998)) of this Review. Some later papers are now obsolete and have been omitted. They were last listed in our PDG 2014 edition: K. Olive, $\mathit et~al.$ (Particle Data Group), Chinese Physics C38 070001 (2014) (http://pdg.lbl.gov).

VALUE (GeV) CL% DOCUMENT ID TECN  COMMENT
$> 680$ 95 1
 2019 AU
ATL 0, 1, 2 or more ${{\mathit \ell}}$, ${{\mathit H}}$ ( $\rightarrow$ ${{\mathit \gamma}}{{\mathit \gamma}}$ , ${{\mathit b}}{{\mathit b}}$ , ${{\mathit W}}{{\mathit W}^{*}}$ , ${{\mathit Z}}{{\mathit Z}^{*}}$ , ${{\mathit \tau}}{{\mathit \tau}}$ ) (various searches), Tchi1n2E, ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{1}}^{0}}}$=0 GeV
$>112$ 95 2
 2019 BU
CMS ${{\mathit p}}$ ${{\mathit p}}$ $\rightarrow$ ${{\widetilde{\mathit \chi}}_{{1}}^{+}}{{\widetilde{\mathit \chi}}_{{2}}^{0}}$ + 2 jets, ${{\widetilde{\mathit \chi}}_{{2}}^{0}}$ $\rightarrow$ ${{\mathit \ell}^{+}}{{\mathit \ell}^{-}}{{\widetilde{\mathit \chi}}_{{1}}^{0}}$ , heavy sleptons, ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{2}}^{0}}}$ $−$ ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{1}}^{0}}}$ = 1 GeV, ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{2}}^{0}}}$ = ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{1}}^{+}}}$
$>215$ 95 2
 2019 BU
CMS ${{\mathit p}}$ ${{\mathit p}}$ $\rightarrow$ ${{\widetilde{\mathit \chi}}_{{1}}^{+}}{{\widetilde{\mathit \chi}}_{{2}}^{0}}$ + 2 jets, ${{\widetilde{\mathit \chi}}_{{2}}^{0}}$ $\rightarrow$ ${{\mathit \ell}^{+}}{{\mathit \ell}^{-}}{{\widetilde{\mathit \chi}}_{{1}}^{0}}$ , heavy sleptons, ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{2}}^{0}}}$ $−$ ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{1}}^{0}}}$ = 30 GeV, ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{2}}^{0}}}$ = ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{1}}^{+}}}$
$> 760$ 95 3
 2018 AY
ATLS 2${{\mathit \tau}}+\not E_T$, Tchi1n2D and ${{\widetilde{\mathit \tau}}_{{L}}}$-only, ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{1}}^{0}}}$ = 0 GeV
$> 1125$ 95 4
 2018 BT
ATLS 2,3${{\mathit \ell}}+\not E_T$, Tchi1n2C, ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{1}}^{0}}}$=0 GeV
$\bf{> 580}$ 95 5
 2018 BT
ATLS 2,3${{\mathit \ell}}+\not E_T$, Tchi1n2F, ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{1}}^{0}}}$=0 GeV
$\text{none 130 - 230, 290 - 880}$ 95 6
 2018 CK
ATLS 2${{\mathit H}}$ ( $\rightarrow$ ${{\mathit b}}{{\mathit b}}$ )+$\not E_T$,Tn1n1A, GMSB
$\text{none 220 - 600}$ 95 7
 2018 CO
ATLS 2,3${{\mathit \ell}}$ + $\not E_T$, recursive jigsaw, Tchi1n2F, ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{1}}^{0}}}$ = 0 GeV
$> 145$ 95 8
 2018 R
ATLS 2${{\mathit \ell}}$ (soft) + $\not E_T$, Tchi1n2G, higgsino, ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{2}}^{0}}}$ $−$ ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{1}}^{0}}}$ = 5 GeV
$> 175$ 95 9
 2018 R
ATLS 2${{\mathit \ell}}$ (soft) + $\not E_T$, Tchi1n2F, wino, ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{2}}^{0}}}$ $−$ ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{1}}^{0}}}$ = 10 GeV
$> 1060$ 95 10
 2018 U
ATLS 2 ${{\mathit \gamma}}$ + $\not E_T$, GGM,Tchi1chi1A, any NLSP mass
$> 167$ 95 11
 2018 AJ
CMS 2${{\mathit \ell}}$ (soft) + $\not E_T$, Tchi1n2G, higgsino, ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{2}}^{0}}}$ $−$ ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{1}}^{0}}}$ = 15 GeV
$> 710$ 95 12
 2018 DP
CMS 2${{\mathit \tau}}+\not E_T$, Tchi1n2D, ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{1}}^{0}}}$ = 0 GeV
$\text{none 220 - 490}$ 95 13
 2017 AW
CMS 1${{\mathit \ell}}$+ 2 ${{\mathit b}}$-jets + $\not E_T$, Tchi1n2E, ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{1}}^{0}}}$ = 0 GeV
$>600$ 95 14
 2016 AA
ATLS 3,4${{\mathit \ell}}$ + $\not E_T$, Tn2n3A, ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{1}}^{0}}}$=0GeV
$>670$ 95 14
 2016 AA
ATLS 3,4${{\mathit \ell}}+\not E_T$,Tn2n3B,${\mathit m}_{{{\widetilde{\mathit \chi}}_{{1}}^{0}}}<$ 200GeV
$>250$ 95 15
 2015 BA
ATLS ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{1}}^{\pm}}}$ = ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{2}}^{0}}}$, ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{1}}^{0}}}$ = 0 GeV
$> 380$ 95 16
 2014 H
ATLS ${{\widetilde{\mathit \chi}}_{{1}}^{\pm}}$ ${{\widetilde{\mathit \chi}}_{{2}}^{0}}$ $\rightarrow$ ${{\mathit \tau}^{\pm}}{{\mathit \nu}}{{\widetilde{\mathit \chi}}_{{1}}^{0}}{{\mathit \tau}^{\pm}}{{\mathit \tau}^{\mp}}{{\widetilde{\mathit \chi}}_{{1}}^{0}}$ , simplified model, ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{1}}^{\pm}}}$ = ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{2}}^{0}}}$, ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{1}}^{0}}}$ = 0 GeV
$> 700$ 95 16
 2014 H
ATLS ${{\widetilde{\mathit \chi}}_{{1}}^{\pm}}$ ${{\widetilde{\mathit \chi}}_{{2}}^{0}}$ $\rightarrow$ ${{\mathit \ell}^{\pm}}{{\mathit \nu}}{{\widetilde{\mathit \chi}}_{{1}}^{0}}{{\mathit \ell}^{\pm}}{{\mathit \ell}^{\mp}}{{\widetilde{\mathit \chi}}_{{1}}^{0}}$ , simplified model, ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{1}}^{\pm}}}$ = ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{2}}^{0}}}$, ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{1}}^{0}}}$ = 0 GeV
$> 345$ 95 16
 2014 H
ATLS ${{\widetilde{\mathit \chi}}_{{1}}^{\pm}}$ ${{\widetilde{\mathit \chi}}_{{2}}^{0}}$ $\rightarrow$ ${{\mathit W}}{{\widetilde{\mathit \chi}}_{{1}}^{0}}{{\mathit Z}}{{\widetilde{\mathit \chi}}_{{1}}^{0}}$ , simplified model, ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{1}}^{\pm}}}$ = ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{2}}^{0}}}$, ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{1}}^{0}}}$ = 0 GeV
$> 148$ 95 16
 2014 H
ATLS ${{\widetilde{\mathit \chi}}_{{1}}^{\pm}}$ ${{\widetilde{\mathit \chi}}_{{2}}^{0}}$ $\rightarrow$ ${{\mathit W}}{{\widetilde{\mathit \chi}}_{{1}}^{0}}{{\mathit H}}{{\widetilde{\mathit \chi}}_{{1}}^{0}}$ , simplified model, ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{1}}^{\pm}}}$ = ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{2}}^{0}}}$, ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{1}}^{0}}}$ = 0 GeV
$> 620$ 95 17
 2014 X
ATLS ${}\geq{}4{{\mathit \ell}^{\pm}}$, ${{\widetilde{\mathit \chi}}_{{2,3}}^{0}}$ $\rightarrow$ ${{\mathit \ell}^{\pm}}{{\mathit \ell}^{\mp}}{{\widetilde{\mathit \chi}}_{{1}}^{0}}$ , ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{1}}^{0}}}$ = 0 GeV
18
 2013
ATLS 3${{\mathit \ell}^{\pm}}$ + $\not E_T$, pMSSM, SMS
19
 2012 BJ
CMS ${}\geq{}$2 ${{\mathit \ell}}$, jets + $\not E_T$, ${{\mathit p}}$ ${{\mathit p}}$ $\rightarrow$ ${{\widetilde{\mathit \chi}}_{{1}}^{\pm}}{{\widetilde{\mathit \chi}}_{{2}}^{0}}$
$\bf{> 62.4}$ 95 20
 2000 W
DLPH ${{\widetilde{\mathit \chi}}_{{2}}^{0}}$, 1${}\leq{}$tan $\beta {}\leq{}$40, all $\Delta \mathit m$, all $\mathit m_{0}$
$\bf{> 99.9}$ 95 20
 2000 W
DLPH ${{\widetilde{\mathit \chi}}_{{3}}^{0}}$, 1${}\leq{}$tan $\beta {}\leq{}$40, all $\Delta \mathit m$, all $\mathit m_{0}$
$\bf{> 116.0}$ 95 20
 2000 W
DLPH ${{\widetilde{\mathit \chi}}_{{4}}^{0}}$, 1${}\leq{}$tan $\beta {}\leq{}$40, all $\Delta \mathit m$, all $\mathit m_{0}$
• • • We do not use the following data for averages, fits, limits, etc. • • •
$\text{none 180 - 355}$ 95 21
 2014 G
ATLS ${{\widetilde{\mathit \chi}}_{{1}}^{\pm}}$ ${{\widetilde{\mathit \chi}}_{{2}}^{0}}$ $\rightarrow$ ${{\mathit W}}{{\widetilde{\mathit \chi}}_{{1}}^{0}}{{\mathit Z}}{{\widetilde{\mathit \chi}}_{{1}}^{0}}$ , simplified model, ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{1}}^{\pm}}}$ = ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{2}}^{0}}}$, ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{1}}^{0}}}$ = 0 GeV
22
 2014 I
CMS ${{\widetilde{\mathit \chi}}_{{2}}^{0}}$ $\rightarrow$ ( ${{\mathit Z}}$ , ${{\mathit H}}$) ${{\widetilde{\mathit \chi}}_{{1}}^{0}}$ ${{\widetilde{\mathit \ell}}}{{\mathit \ell}}$ , simplified model
23
 2012 AS
ATLS 3${{\mathit \ell}^{\pm}}$ + $\not E_T$, pMSSM
24
 2012 T
ATLS ${{\mathit \ell}^{\pm}}{{\mathit \ell}^{\pm}}$ + $\not E_T$, ${{\mathit p}}$ ${{\mathit p}}$ $\rightarrow$ ${{\widetilde{\mathit \chi}}_{{1}}^{\pm}}{{\widetilde{\mathit \chi}}_{{2}}^{0}}$
1  AABOUD 2019AU searched in 36.1 ${\mathrm {fb}}{}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 13 TeV for direct electroweak production of charginos and next-to-lightest neutralinos decaying into lightest neutralinos and a ${{\mathit W}}$ and a Higgs boson, respectively. Fully hadronic, semileptonic, diphoton, and multilepton (electrons, muons) final states with missing transverse momentum are considered in this search. Observations are consistent with the Standard Model expectations, and 95$\%$ confidence-level limits of up to 680 GeV on the chargino/next-to-lightest neutralino masses are set (Tchi1n2E model). See their Figure 14 for an overlay of exclusion contours from all searches.
2  SIRUNYAN 2019BU searched for pair production of gauginos via vector boson fusion assuming the gaugino spectrum is compressed, in 35.9 ${\mathrm {fb}}{}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 13 TeV. The final states explored included zero leptons plus two jets, one lepton plus two jets, and one hadronic tau plus two jets. A similar bound is obtained in the light slepton limit.
3  AABOUD 2018AY searched in 36.1 ${\mathrm {fb}}{}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 13 TeV for direct electroweak production of charginos and neutralinos as in Tchi1n2D models, in events characterised by the presence of at least two hadronically decaying tau leptons and large missing transverse energy. No significant deviation from the expected SM background is observed. Assuming decays via intermediate ${{\widetilde{\mathit \tau}}_{{L}}}$ and ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{1}}^{\pm}}}$ = ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{2}}^{0}}}$, the observed limits rule out ${{\widetilde{\mathit \chi}}_{{2}}^{0}}$ masses up to 760 GeV for a massless ${{\widetilde{\mathit \chi}}_{{1}}^{0}}$. See their Fig.7 (right). Interpretations are also provided in Fig 8 (bottom) for different assumptions on the ratio between ${\mathit m}_{{{\widetilde{\mathit \tau}}}}$ and ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{2}}^{0}}}$ + ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{1}}^{0}}}$.
4  AABOUD 2018BT searched in 36.1 ${\mathrm {fb}}{}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 13 TeV for direct electroweak production of charginos, chargino and next-to-lightest neutralinos and sleptons in events with two or three leptons (electrons or muons), with or without jets, and large missing transverse energy. No significant excess above the Standard Model expectations is observed. Limits are set on the next-to-lightest neutralino mass up to 1100 GeV for massless ${{\widetilde{\mathit \chi}}_{{1}}^{0}}$ in the Tchi1n2C simplified model exploiting the 3${{\mathit \ell}}$ signature, see their Figure 8(c).
5  AABOUD 2018BT searched in 36.1 ${\mathrm {fb}}{}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 13 TeV for direct electroweak production of charginos, chargino and next-to-lightest neutralinos and sleptons in events with two or three leptons (electrons or muons), with or without jets, and large missing transverse energy. No significant excess above the Standard Model expectations is observed. Limits are set on the next-to-lightest neutralino mass up to 580 GeV for massless ${{\widetilde{\mathit \chi}}_{{1}}^{0}}$ in the Tchi1n2F simplified model exploiting the 2${{\mathit \ell}}$+2 jets and 3${{\mathit \ell}}$ signatures, see their Figure 8(d).
6  AABOUD 2018CK searched for events with at least 3 ${{\mathit b}}$-jets and large missing transverse energy in two datasets of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 13 TeV of 36.1 ${\mathrm {fb}}{}^{-1}$ and 24.3 ${\mathrm {fb}}{}^{-1}$ depending on the trigger requirements. The analyses aimed to reconstruct two Higgs bosons decaying to pairs of ${{\mathit b}}$-quarks. No significant excess above the Standard Model expectations is observed. Limits are set on the Higgsino mass in the T1n1n1A simplified model, see their Figure 15(a). Constraints are also presented as a function of the BR of Higgsino decaying into an higgs boson and a gravitino, see their Figure 15(b).
7  AABOUD 2018CO searched in 36.1 ${\mathrm {fb}}{}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 13 TeV for direct electroweak production of mass-degenerate charginos and next-to-lightest neutralinos in events with two or three leptons (electrons or muons), with or without jets, and large missing transverse energy. The search channels are based on recursive jigsaw reconstruction. Limits are set on the next-to-lightest neutralinos mass up to 600 GeV for massless neutralinos in the Tchi1n2F simplified model exploiting the statistical combination of 2${{\mathit \ell}}$+2 jets and 3${{\mathit \ell}}$ channels. Next-to-lightest neutralinos masses below 220 GeV are not excluded due to an excess of events above the SM prediction in the dedicated regions. See their Figure 13(d).
8  AABOUD 2018R searched in 36.1 ${\mathrm {fb}}{}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 13 TeV for electroweak production in scenarios with compressed mass spectra in final states with two low-momentum leptons and missing transverse momentum. The data are found to be consistent with the SM prediction. Results are interpreted in Tchi1n2G higgsino models, and ${{\widetilde{\mathit \chi}}_{{2}}^{0}}$ masses are excluded up to 145 GeV for ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{2}}^{0}}}$ $−$ ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{1}}^{0}}}$ = 5 GeV. The exclusion limits extend down to mass splittings of 2.5 GeV, see their Fig. 10 (top). Results are also interpreted in terms of exclusion bounds on the production cross-sections for the NUHM2 scenario as a function of the universal gaugino mass ${\mathit m}_{\mathrm {1/2}}$ and ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{2}}^{0}}}$ $−$ ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{1}}^{0}}}$, see their Fig. 12.
9  AABOUD 2018R searched in 36.1 ${\mathrm {fb}}{}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 13 TeV for electroweak production in scenarios with compressed mass spectra in final states with two low-momentum leptons and missing transverse momentum. The data are found to be consistent with the SM prediction. Results are interpreted in Tchi1n2F wino models, and ${{\widetilde{\mathit \chi}}_{{2}}^{0}}$ masses are excluded up to 175 GeV for ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{2}}^{0}}}$ $−$ ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{1}}^{0}}}$ = 10 GeV. The exclusion limits extend down to mass splittings of 2 GeV, see their Fig. 10 (bottom). Results are also interpreted in terms of exclusion bounds on the production cross-sections for the NUHM2 scenario as a function of the universal gaugino mass ${\mathit m}_{\mathrm {1/2}}$ and ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{2}}^{0}}}$ $−$ ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{1}}^{0}}}$, see their Fig. 12.
10  AABOUD 2018U searched in 36.1 ${\mathrm {fb}}{}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 13 TeV in events with at least one isolated photon, possibly jets and significant transverse momentum targeting generalised models of gauge-mediated SUSY breaking. No significant excess of events is observed above the SM prediction. Results of the diphoton channel are interpreted in terms of lower limits on the masses of gauginos Tchi1chi1A models, which reach as high as 1.3 TeV. Gaugino masses below 1060 GeV are excluded for any NLSP mass, see their Fig. 10.
11  SIRUNYAN 2018AJ searched in 35.9 ${\mathrm {fb}}{}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 13 TeV for events containing two low-momentum, oppositely charged leptons (electrons or muons) and $\not E_T$. No excess over the expected background is observed. Limits are derived on the wino mass in the Tchi1n2F simplified model, see their Figure 5. Limits are also set on the stop mass in the Tstop10 simplified model, see their Figure 6. Finally, limits are set on the Higgsino mass in the Tchi1n2G simplified model, see Figure 8 and in the pMSSM, see Figure 7.
12  SIRUNYAN 2018DP searched in 35.9 ${\mathrm {fb}}{}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 13 TeV for direct electroweak production of charginos and neutralinos or of chargino pairs in events with a tau lepton pair and significant missing transverse momentum. Both hadronic and leptonic decay modes are considered for the tau lepton. No significant excess above the Standard Model expectations is observed. Limits are set on the chargino mass in the Tchi1chi1D and Tchi1n2 simplified models, see their Figures 14 and 15. Also, excluded stau pair production cross sections are shown in Figures 11, 12, and 13.
13  SIRUNYAN 2017AW searched in 35.9 ${\mathrm {fb}}{}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 13 TeV for events with a charged lepton (electron or muon), two jets identified as originating from a ${{\mathit b}}$-quark, and large $\not E_T$. No significant excess above the Standard Model expectations is observed. Limits are set on the mass of the chargino and the next-to-lightest neutralino in the Tchi1n2E simplified model, see their Figure 6.
14  AAD 2016AA summarized and extended ATLAS searches for electroweak supersymmetry in final states containing several charged leptons, $\not E_T$, with or without hadronic jets, in 20 ${\mathrm {fb}}{}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 8 TeV. The paper reports the results of new interpretations and statistical combinations of previously published analyses, as well as new analyses. Exclusion limits at 95$\%$ C.L. are set on mass-degenerate ${{\widetilde{\mathit \chi}}_{{2}}^{0}}$ and ${{\widetilde{\mathit \chi}}_{{3}}^{0}}$ masses in the Tn2n3A and Tn2n3B simplified models. See their Fig. 15.
15  AAD 2015BA searched in 20.3 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 8 TeV for electroweak production of charginos and neutralinos decaying to a final state containing a ${{\mathit W}}$ boson and a 125 GeV Higgs boson, plus missing transverse momentum. No excess beyond the Standard Model expectation is observed. Exclusion limits are derived in simplified models of direct chargino and next-to-lightest neutralino production, with the decays ${{\widetilde{\mathit \chi}}_{{1}}^{\pm}}$ $\rightarrow$ ${{\mathit W}^{\pm}}{{\widetilde{\mathit \chi}}_{{1}}^{0}}$ and ${{\widetilde{\mathit \chi}}_{{2}}^{0}}$ $\rightarrow$ ${{\mathit H}}{{\widetilde{\mathit \chi}}_{{1}}^{0}}$ having 100$\%$ branching fraction, see Fig. 8. A combination of the multiple final states for the Higgs decay yields the best limits (Fig. 8d).
16  AAD 2014H searched in 20.3 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 8 TeV for electroweak production of charginos and neutralinos decaying to a final sate with three leptons and missing transverse momentum. No excess beyond the Standard Model expectation is observed. Exclusion limits are derived in simplified models of direct chargino and next-to-lightest neutralino production, with decays to the lightest neutralino via either all three generations of leptons, staus only, gauge bosons, or Higgs bosons, see Fig. 7. An interpretation in the pMSSM is also given, see Fig. 8.
17  AAD 2014X searched in 20.3 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 8 TeV for events with at least four leptons (electrons, muons, taus) in the final state. No significant excess above the Standard Model expectations is observed. Limits are set on the neutralino mass in an R-parity conserving simplified model where the decay ${{\widetilde{\mathit \chi}}_{{2,3}}^{0}}$ $\rightarrow$ ${{\mathit \ell}^{\pm}}{{\mathit \ell}^{\mp}}{{\widetilde{\mathit \chi}}_{{1}}^{0}}$ takes place with a branching ratio of 100$\%$, see Fig. 10.
18  AAD 2013 searched in 4.7 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 7 TeV for charginos and neutralinos decaying to a final state with three leptons (${{\mathit e}}$ and ${{\mathit \mu}}$) and missing transverse energy. No excess beyond the Standard Model expectation is observed. Exclusion limits are derived in the phenomenological MSSM, see Fig. 2 and 3, and in simplified models, see Fig. 4. For the simplified models with intermediate slepton decays, degenerate ${{\widetilde{\mathit \chi}}_{{1}}^{\pm}}$ and ${{\widetilde{\mathit \chi}}_{{2}}^{0}}$ masses up to 500 GeV are excluded at 95$\%$ C.L. for very large mass differences with the ${{\widetilde{\mathit \chi}}_{{1}}^{0}}$. Supersedes AAD 2012AS.
19  CHATRCHYAN 2012BJ searched in 4.98 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 7 TeV for direct electroweak production of charginos and neutralinos in events with at least two leptons, jets and missing transverse momentum. No significant excesses over the expected SM backgrounds are observed and 95$\%$ C.L. limits on the production cross section of ${{\widetilde{\mathit \chi}}_{{1}}^{\pm}}{{\widetilde{\mathit \chi}}_{{2}}^{0}}$ pair production were set in a number of simplified models, see Figs. 7 to 12. Most limits are for exactly 3 jets.
20  ABREU 2000W combines data collected at $\sqrt {\mathit s }$=189 GeV with results from lower energies. The mass limit is obtained by constraining the MSSM parameter space with gaugino and sfermion mass universality at the GUT scale, using the results of negative direct searches for neutralinos (including cascade decays and ${{\widetilde{\mathit \tau}}}{{\mathit \tau}}$ final states) from ABREU 2001 , for charginos from ABREU 2000J and ABREU 2000T (for all $\Delta \mathit m_{+}$), and for charged sleptons from ABREU 2001B. The results hold for the full parameter space defined by all values of $\mathit M_{2}$ and $\vert \mu \vert {}\leq{}$2 TeV with the ${{\widetilde{\mathit \chi}}_{{1}}^{0}}$ as LSP.
21  AAD 2014G searched in 20.3 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 8 TeV for electroweak production of chargino-neutralino pairs, decaying to a final sate with two leptons (${{\mathit e}}$ and ${{\mathit \mu}}$) and missing transverse momentum. No excess beyond the Standard Model expectation is observed. Exclusion limits are derived in simplified models of chargino and next-to-lightest neutralino production, with decays to the lightest neutralino via gauge bosons, see Fig. 7. An interpretation in the pMSSM is also given, see Fig. 10.
22  KHACHATRYAN 2014I searched in 19.5 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 8 TeV for electroweak production of charginos and neutralinos decaying to a final state with three leptons (${{\mathit e}}$ or ${{\mathit \mu}}$) and missing transverse momentum, or with a ${{\mathit Z}}$-boson, dijets and missing transverse momentum. No excess beyond the Standard Model expectation is observed. Exclusion limits are derived in simplified models, see Figs. $12 - 16$.
23  AAD 2012AS searched in 2.06 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 7 TeV for charginos and neutralinos decaying to a final state with three leptons (${{\mathit e}}$ and ${{\mathit \mu}}$) and missing transverse energy. No excess beyond the Standard Model expectation is observed. Exclusion limits are derived in the phenomenological MSSM, see Fig. 2 (top), and in simplified models, see Fig. 2 (bottom).
24  AAD 2012T looked in 1 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 7 TeV for the production of supersymmetric particles decaying into final states with missing transverse momentum and exactly two isolated leptons (${{\mathit e}}$ or ${{\mathit \mu}}$). Same-sign dilepton events were separately studied. Additionally, in opposite-sign events, a search was made for an excess of same-flavor over different-flavor lepton pairs. No excess over the expected background is observed and limits are placed on the effective production cross section of opposite-sign dilepton events with $\not E_T$ $>$ 250 GeV and on same-sign dilepton events with $\not E_T$ $>$ 100 GeV. The latter limit is interpreted in a simplified electroweak gaugino production model.
References:
 AABOUD 2019AU
PR D100 012006 Search for chargino and neutralino production in final states with a Higgs boson and missing transverse momentum at $\sqrt{s} = 13$ TeV with the ATLAS detector
 SIRUNYAN 2019BU
JHEP 1908 150 Search for supersymmetry with a compressed mass spectrum in the vector boson fusion topology with 1-lepton and 0-lepton final states in proton-proton collisions at $\sqrt{s}=$ 13 TeV
 AABOUD 2018BT
EPJ C78 995 Search for electroweak production of supersymmetric particles in final states with two or three leptons at $\sqrt{s}=13\,$TeV with the ATLAS detector
 AABOUD 2018AY
EPJ C78 154 Search for the direct production of charginos and neutralinos in final states with tau leptons in $\sqrt{s} =$ 13 TeV $pp$ collisions with the ATLAS detector
 AABOUD 2018R
PR D97 052010 Search for electroweak production of supersymmetric states in scenarios with compressed mass spectra at $\sqrt{s}=13$ TeV with the ATLAS detector
 AABOUD 2018U
PR D97 092006 Search for photonic signatures of gauge-mediated supersymmetry in 13 TeV $pp$ collisions with the ATLAS detector
 AABOUD 2018CO
PR D98 092012 Search for chargino-neutralino production using recursive jigsaw reconstruction in final states with two or three charged leptons in proton-proton collisions at $\sqrt{s}=13$ TeV with the ATLAS detector
 AABOUD 2018CK
PR D98 092002 Search for pair production of higgsinos in final states with at least three $b$-tagged jets in $\sqrt{s} = 13$ TeV $pp$ collisions using the ATLAS detector
 SIRUNYAN 2018DP
JHEP 1811 151 Search for supersymmetry in events with a $\tau$ lepton pair and missing transverse momentum in proton-proton collisions at $\sqrt{s} =$ 13 TeV
 SIRUNYAN 2018AJ
PL B782 440 Search for new physics in events with two soft oppositely charged leptons and missing transverse momentum in proton-proton collisions at $\sqrt{s}=$ 13 TeV
 SIRUNYAN 2017AW
JHEP 1711 029 Search for Electroweak Production of Charginos and Neutralinos in ${{\mathit W}}{{\mathit H}}$ Events in Proton-Proton Collisions at $\sqrt {s }$ = 13 TeV
PR D93 052002 Search for the Electroweak Production of Supersymmetric Particles in $\sqrt {s }$ = 8 TeV ${{\mathit p}}{{\mathit p}}$ Collisions with the ATLAS Detector
EPJ C75 208 Search for Direct Pair Production of a Chargino and a Neutralino Decaying to the 125 GeV Higgs Boson in $\sqrt {s }$ = 8 TeV ${{\mathit p}}{{\mathit p}}$ Collisions with the ATLAS Detector
JHEP 1405 071 Search for Direct Production of charginos, neutralinos and sleptons in Final States with Two Leptons and Missing Transverse Momentum in ${{\mathit p}}{{\mathit p}}$ Collisions at $\sqrt {s }$ = 8 TeV with the ATLAS Detector
JHEP 1404 169 Search for Direct Production of Charginos and Neutralinos in Events with Three Leptons and Missing Transverse Momentum in $\sqrt {s }$ = 8 TeV ${{\mathit p}}{{\mathit p}}$ Collisions with the ATLAS Detector
PR D90 052001 Search for Supersymmetry in Events with Four or More Leptons in $\sqrt {s }$ = 8 TeV ${{\mathit p}}{{\mathit p}}$ Collisions with the ATLAS Detector
EPJ C74 3036 Searches for Electroweak Production of charginos, neutralinos, and sleptons Decaying to Leptons and ${{\mathit W}}$, ${{\mathit Z}}$, and Higgs Bosons in ${{\mathit p}}{{\mathit p}}$ Collisions at 8 TeV
PL B718 841 Search for Direct Production of Charginos and Neutralinos in Events with Three Leptons and Missing Transverse Momentum in $\sqrt {s }$ = 7 TeV ${{\mathit p}}{{\mathit p}}$ Collisions with the ATLAS Detector
PL B709 137 Searches for Supersymmetry with the ATLAS Detector using Final States with Two Leptons and Missing Transverse Momentum in $\sqrt {s }$ = 7 TeV Proton$−$Proton Collisions
PRL 108 261804 Search for Supersymmetry in Events with Three Leptons and Missing Transverse Momentum in $\sqrt {s }$ = 7 TeV ${{\mathit p}}{{\mathit p}}$ Collisions with the ATLAS Detector
JHEP 1211 147 Search for Electroweak Production of Charginos and Neutralinos using Leptonic Final States in ${{\mathit p}}{{\mathit p}}$ Collisions at $\sqrt {s }$ = 7 TeV
PL B489 38 Limits on the Masses of Supersymmetric Particles at $\sqrt {s }$ = 189-GeV