A search for Supersymmetry involving the pair production of gluinos decaying via third-generation squarks to the lightest neutralino is reported. It uses an LHC proton--proton dataset at a center-of-mass energy $\sqrt{s} = 13$ TeV with an integrated luminosity of 3.2 fb$^{-1}$ collected with the ATLAS detector in 2015. The signal is searched for in events containing several energetic jets, of which at least three must be identified as $b$-jets, large missing transverse momentum and, potentially, isolated electrons or muons. Large-radius jets with a high mass are also used to identify highly boosted top quarks. No excess is found above the predicted background. For neutralino masses below approximately 700 GeV, gluino masses of less than 1.78 TeV and 1.76 TeV are excluded at the 95% CL in simplified models of the pair production of gluinos decaying via sbottom and stop, respectively. These results significantly extend the exclusion limits obtained with the $\sqrt{s} = 8$ TeV dataset.
Distribution of missing transverse energy for SR-Gbb-B.
Distribution of missing transverse energy for SR-Gtt-0L-C.
Distribution of missing transverse energy for SR-Gtt-1L-A.
The results of a search for gluinos in final states with an isolated electron or muon, multiple jets and large missing transverse momentum using proton--proton collision data at a centre-of-mass energy of $\sqrt{s}$ = 13 TeV are presented. The dataset used was recorded in 2015 by the ATLAS experiment at the Large Hadron Collider and corresponds to an integrated luminosity of 3.2 fb$^{-1}$. Six signal selections are defined that best exploit the signal characteristics. The data agree with the Standard Model background expectation in all six signal selections, and the largest deviation is a 2.1 standard deviation excess. The results are interpreted in a simplified model where pair-produced gluinos decay via the lightest chargino to the lightest neutralino. In this model, gluinos are excluded up to masses of approximately 1.6 TeV depending on the mass spectrum of the simplified model, thus surpassing the limits of previous searches.
The distribution of the missing transverse momentum is shown in hard-lepton 6-jet ttbar control regions after normalising the ttbar and W+jets background processes in the simultaneous fit.
The distribution of the missing transverse momentum is shown in hard-lepton 6-jet W+jets control regions after normalising the ttbar and W+jets background processes in the simultaneous fit.
The distribution of the missing transverse momentum is shown in soft-lepton 2-jet ttbar control regions after normalising the ttbar and W+jets background processes in the simultaneous fit.
A search for squarks and gluinos in final states containing hadronic jets, missing transverse momentum but no electrons or muons is presented. The data were recorded in 2015 by the ATLAS experiment in $\sqrt{s}=$ 13 TeV proton--proton collisions at the Large Hadron Collider. No excess above the Standard Model background expectation was observed in 3.2 fb$^{-1}$ of analyzed data. Results are interpreted within simplified models that assume R-parity is conserved and the neutralino is the lightest supersymmetric particle. An exclusion limit at the 95% confidence level on the mass of the gluino is set at 1.51 TeV for a simplified model incorporating only a gluino octet and the lightest neutralino, assuming the lightest neutralino is massless. For a simplified model involving the strong production of mass-degenerate first- and second-generation squarks, squark masses below 1.03 TeV are excluded for a massless lightest neutralino. These limits substantially extend the region of supersymmetric parameter space excluded by previous measurements with the ATLAS detector.
Observed and expected background effective mass distributions in control region CRgamma for SR4jt.
Observed and expected background effective mass distributions in control region CRW for SR4jt.
Observed and expected background effective mass distributions in control region CRT for SR4jt.
Results from a search for supersymmetry in events with four or more leptons including electrons, muons and taus are presented. The analysis uses a data sample corresponding to 20.3 $fb^{-1}$ of proton--proton collisions delivered by the Large Hadron Collider at $\sqrt{s}$ = 8 TeV and recorded by the ATLAS detector. Signal regions are designed to target supersymmetric scenarios that can be either enriched in or depleted of events involving the production of a $Z$ boson. No significant deviations are observed in data from Standard Model predictions and results are used to set upper limits on the event yields from processes beyond the Standard Model. Exclusion limits at the 95% confidence level on the masses of relevant supersymmetric particles are obtained. In R-parity-violating simplified models with decays of the lightest supersymmetric particle to electrons and muons, limits of 1350 GeV and 750 GeV are placed on gluino and chargino masses, respectively. In R-parity-conserving simplified models with heavy neutralinos decaying to a massless lightest supersymmetric particle, heavy neutralino masses up to 620 GeV are excluded. Limits are also placed on other supersymmetric scenarios.
The ETmiss distribution in VR0Z.
The effective mass distribution in VR0Z.
The ETmiss distribution in VR2Z.
A search for strongly produced supersymmetric particles is conducted using signatures involving multiple energetic jets and either two isolated leptons ($e$ or $\mu$) with the same electric charge, or at least three isolated leptons. The search also utilises jets originating from b-quarks, missing transverse momentum and other observables to extend its sensitivity. The analysis uses a data sample corresponding to a total integrated luminosity of 20.3 fb$^{-1}$ of $\sqrt{s} =$ 8 TeV proton-proton collisions recorded with the ATLAS detector at the Large Hadron Collider in 2012. No deviation from the Standard Model expectation is observed. New or significantly improved exclusion limits are set on a wide variety of supersymmetric models in which the lightest squark can be of the first, second or third generations, and in which R-parity can be conserved or violated.
Numbers of observed and background events for SR0b for each bin of the distribution in Meff. The table corresponds to Fig. 4(b). The statistical and systematic uncertainties are combined for the expected backgrounds.
Numbers of observed and background events for SR1b for each bin of the distribution in Meff. The table corresponds to Fig. 4(c). The statistical and systematic uncertainties are combined for the predicted numbers.
Numbers of observed and background events for SR3b for each bin of the distribution in Meff. The table corresponds to Fig. 4(a). The statistical and systematic uncertainties are combined for the predicted numbers.
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