Search for direct production of electroweakinos in final states with one lepton, missing transverse momentum and a Higgs boson decaying into two b-jets in $$pp$$ collisions at $$\sqrt{s}=13$$ TeV with the ATLAS detector

Abstract

The results of a search for electroweakino pair production $$pp \rightarrow \tilde{\chi }^\pm _1 \tilde{\chi }^0_2$$pp→χ~1±χ~20 in which the chargino ($$\tilde{\chi }^\pm _1$$χ~1±) decays into a W boson and the lightest neutralino ($$\tilde{\chi }^0_1$$χ~10), while the heavier neutralino ($$\tilde{\chi }^0_2$$χ~20) decays into the Standard Model 125 GeV Higgs boson and a second $$\tilde{\chi }^0_1$$χ~10 are presented. The signal selection requires a pair of b-tagged jets consistent with those from a Higgs boson decay, and either an electron or a muon from the W boson decay, together with missing transverse momentum from the corresponding neutrino and the stable neutralinos. The analysis is based on data corresponding to 139 $$\mathrm {fb}^{-1}$$fb-1 of $$\sqrt{s}=13$$s=13 TeV pp collisions provided by the Large Hadron Collider and recorded by the ATLAS detector. No statistically significant evidence of an excess of events above the Standard Model expectation is found. Limits are set on the direct production of the electroweakinos in simplified models, assuming pure wino cross-sections. Masses of $$\tilde{\chi }^{\pm }_{1}/\tilde{\chi }^{0}_{2}$$χ~1±/χ~20 up to 740 GeV are excluded at 95% confidence level for a massless $$\tilde{\chi }^{0}_{1}$$χ~10.

Reinterpretation of LHC Results for New Physics: Status and recommendations after Run 2

“…There is another way to ensure the correct operation of analysis-recasting programs: for the experiments to publish their own, validated versions. This is now regularly attempted by AT-LAS SUSY analyses as additional resources in HEPData submissions, effectively in pseudocode from the perspective of external recasters [24,29,30,[44][45][46][47]. This is a highly welcome development, that has proven extremely helpful in some cases, and we greatly encourage that it be pursued further.…”

Constraining electroweakinos in the minimal Dirac gaugino model

“…We note in this context that, while this study was finalised, ATLAS made pyhf likelihood files for the 1l + H(→ bb)+ E miss T EW-ino search [107] available on HEPData [136] in addition to digitised acceptance and efficiency maps. We appreciate this very much and are looking forward to using this data in future studies.…”

“…ATLAS reported a search in final states with E miss T , 1 lepton (e or µ) and a Higgs boson decaying into bb, with 139 fb −1 in [107]. This is particularly powerful for searching for winos with a lighter LSP (such as a bino or higgsino) and so we implemented a recast of this analysis in MadAnalysis 5 [113][114][115][116].…”

“…This is particularly powerful for searching for winos with a lighter LSP (such as a bino or higgsino) and so we implemented a recast of this analysis in MadAnalysis 5 [113][114][115][116]. The analysis targets electroweakinos produced in the combination Table 5: Number of events expected in each signal region in [107] (columns labelled "ATLAS") against result from recasting in MadAnalysis 5 (columns labelled "MA") for different parameter points. The quoted error bands are Monte Carlo uncertainties, but the cross-section uncertainties can also reach 10% for some regions.…”

“…The implementation in MadAnalysis 5 follows the cuts of [107] and implements the lepton isolation and a jet/lepton removal procedure as described in that paper directly in the analysis. Jet reconstruction is performed using fastjet [138] in Delphes 3 [122], where b-tagging and lepton/jet reconstruction efficiencies are taken from a standard ATLAS Delphes 3 card used in other recasting analyses [139][140][141][142].…”