T. Ekelof

Topological cell clustering in the ATLAS calorimeters and its performance in LHC Run 1

The reconstruction of the signal from hadrons and jets emerging from the proton–proton collisions at the Large Hadron Collider (LHC) and entering the ATLAS calorimeters is based on a three-dimensional topological clustering of individual calorimeter cell signals. The cluster formation follows cell signal-significance patterns generated by electromagnetic and hadronic showers. In this, the clustering algorithm implicitly performs a topological noise suppression by removing cells with insignificant signals which are not in close proximity to cells with significant signals. The resulting topological cell clusters have shape and location information, which is exploited to apply a local energy calibration and corrections depending on the nature of the cluster. Topological cell clustering is established as a well-performing calorimeter signal definition for jet and missing transverse momentum reconstruction in ATLAS.

Search for the Dimuon Decay of the Higgs Boson in pp Collisions at s =13 TeV with the ATLAS Detector

A search for the dimuon decay of the Higgs boson has been performed using data corresponding to an integrated luminosity of 36.1 fb−1 collected with the ATLAS detector in pp collisions at √ s =13 TeV at the LHC. No significant excess is observed above the background expectation. The observed (expected) upper limit on the cross-section times the branching ratio is 3.0 (3.1) times the Standard Model prediction at the 95% confidence level for a Higgs boson mass of 125 GeV. When combined with the pp collisions data at √ s =7 TeV and √ s =8 TeV, the observed (expected) upper limit is 2.8 (2.9) times the Standard Model prediction.A search for the dimuon decay of the Higgs boson was performed using data corresponding to an integrated luminosity of 36.1u2009u2009fb^{-1} collected with the ATLAS detector in pp collisions at sqrt[s]=13u2009u2009TeV at the Large Hadron Collider. No significant excess is observed above the expected background. The observed (expected) upper limit on the cross section times branching ratio is 3.0 (3.1) times the Standard Model prediction at the 95%xa0confidence level for a Higgs boson mass of 125xa0GeV. When combined with the pp collision data at sqrt[s]=7u2009u2009TeV and sqrt[s]=8u2009u2009TeV, the observed (expected) upper limit is 2.8 (2.9) times the Standard Model prediction.

Search for new phenomena with large jet multiplicities and missing transverse momentum using large-radius jets and flavour-tagging at ATLAS in 13 TeV pp collisions

A bstractA search is presented for particles that decay producing a large jet multiplicity and invisible particles. The event selection applies a veto on the presence of isolated electrons or muons and additional requirements on the number of b-tagged jets and the scalar sum of masses of large-radius jets. Having explored the full ATLAS 2015-2016 dataset of LHC proton-proton collisions at s=13

Search for new phenomena in events containing a same-flavour opposite-sign dilepton pair, jets, and large missing transverse momentum in √s = 13 TeV pp collisions with the ATLAS detector

sqrt{s}=13