Search for chargino–neutralino pair production in final states with three leptons and missing transverse momentum in $\sqrt{s} = 13$ TeV pp collisions with the ATLAS detector

Abstract

Abstract A search for chargino–neutralino pair production in three-lepton final states with missing transverse momentum is presented. The study is based on a dataset of

$\sqrt{s} = 13$

s

= 13

TeV pp collisions recorded with the ATLAS detector at the LHC, corresponding to an integrated luminosity of 139

$\hbox {fb}^{-1}$

fb

- 1

. No significant excess relative to the Standard Model predictions is found in data. The results are interpreted in simplified models of supersymmetry, and statistically combined with results from a previous ATLAS search for compressed spectra in two-lepton final states. Various scenarios for the production and decay of charginos (

${\tilde{\chi }}^\pm _1$

χ ~

1 ±

) and neutralinos (

${\tilde{\chi }}^0_2$

χ ~

2 0

) are considered. For pure higgsino

${\tilde{\chi }}^\pm _1{\tilde{\chi }}^0_2$

χ ~

1 ±

χ ~

2 0

pair-production scenarios, exclusion limits at 95% confidence level are set on

${\tilde{\chi }}^0_2$

χ ~

2 0

masses up to 210 GeV. Limits are also set for pure wino

${\tilde{\chi }}^\pm _1{\tilde{\chi }}^0_2$

χ ~

1 ±

χ ~

2 0

pair production, on

${\tilde{\chi }}^0_2$

χ ~

2 0

masses up to 640 GeV for decays via on-shell W and Z bosons, up to 300 GeV for decays via off-shell W and Z bosons, and up to 190 GeV for decays via W and Standard Model Higgs bosons.