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 √ 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

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... ric 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 firstand 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. c 2016 CERN for the benefit of the ATLAS Collaboration. Reproduction of this article or parts of it is allowed as specified in the CC-BY-4.0 license. The ATLAS detector and data samples The ATLAS detector [26] is a multi-purpose detector with a forward-backward symmetric cylindrical geometry and nearly 4π coverage in solid angle. 1 The inner tracking detector (ID) consists of pixel 1 ATLAS uses a right-handed coordinate system with its origin at the nominal interaction point in the centre of the detector. The positive x-axis is defined by the direction from the interaction point to the centre of the LHC ring, with the positive y-axis pointing upwards, while the beam direction defines the z-axis. Cylindrical coordinates (r, φ) are used in the transverse plane, φ being the azimuthal angle around the z-axis. The pseudorapidity η is defined in terms of the polar angle θ by η = − ln tan(θ/2) and the rapidity is defined as y = (1/2) ln[(E + p z )/(E − p z )] where E is the energy and p z the longitudinal momentum of the object of interest. The transverse momentum p T , the transverse energy E T and the missing transverse momentum E miss T are defined in the x-y plane unless stated otherwise.