Search for direct pair production of a chargino and a neutralino decaying to the 125 GeV Higgs boson in $$\sqrt{\varvec{s}} = 8$$ s = 8  TeV $$\varvec{pp}$$ p p collisions with the ATLAS detector

Abstract

A search is presented for the direct pair production of a chargino and a neutralino , where the chargino decays to the lightest neutralino and the boson, , while the neutralino decays to the lightest neutralino and the 125 GeV Higgs boson, . The final states considered for the search have large missing transverse momentum, an isolated electron or muon, and one of the following: either two jets identified as originating from bottom quarks, or two photons, or a second electron or muon with the same electric charge. The analysis is based on 20.3 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with the Standard Model expectations, and limits are set in the context of a simplified supersymmetric model.

Impact of jet veto resummation on slepton searches

“…We chose these signal regions in figure 7, neglecting the possibility that the signal region with the highest expected sensitivity might change within the plotted range. The intersections of the σ 95 0,vis curves with our resummed predictions set our NLL and NLL +NLO exclusion limits, 7 shown by the green and red error bars in the lower panels of the plots. The blue error bars in the lower panels show for comparison the current exclusion limits as quoted by ATLAS, which account for the theory uncertainty on the total cross section (including PDF uncertainties) following ref.…”

“…This amounts to placing a veto on additional jets above a certain transverse momentum p cut T arising from QCD initial-state or final-state radiation. Typical examples are supersymmetry (SUSY) searches for third generation squarks requiring two signal jets and vetoing a third jet [1][2][3], or electroweakino/slepton searches usually requiring 0 signal jets [4][5][6][7][8]. Jet vetoes are also applied in other BSM searches, including anomalous triple-gauge couplings [9], unparticles [10], large extra dimensions and dark matter candidates in mono-photon, mono-Z and mono-jet events [11][12][13].…”

“…[85]. 7 We simply exclude the regions where the calculated 0-jet cross section is larger than the upper limit, σ 95 0,vis , without calculating a CLs value. 8 Note that the Monte Carlo predictions are reweighted to the total NLO cross section.…”

Search for the electroweak production of supersymmetric particles ins=8 TeVppcollisions with the ATLAS detector

“…The direct production of charginos, neutralinos, and sleptons (l) through electroweak (EW) interactions may dominate the SUSY production at the Large Hadron Collider (LHC) if the masses of the gluinos and squarks are large. Previous searches for electroweak SUSY production at ATLAS targeted the production ofl þl− ,τ þτ− ,χ þ 1χ − 1 (decaying throughl or W bosons),χ AE 1χ 0 2 (decaying throughl or W and Z=h bosons), andχ 0 2χ 0 3 (decaying throughl or Z bosons) [19][20][21][22][23], and found no significant excess beyond SM expectations. These searches are typically sensitive to scenarios where there is a relatively large Oðm W;Z Þ splitting between the produced sparticles and the LSP, leaving uncovered territory for smaller mass splittings.…”

“…A series of new analyses targeting regions in parameter space not covered by previous ATLAS analyses [19][20][21][22][23] are presented. The results from new and published searches are combined and reinterpreted to provide the final 8 TeV ATLAS limits on the production of EW SUSY particles in a variety of models.…”