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133 papers found.
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Search for large missing transverse momentum in association with one top-quark in proton-proton collisions at \( \sqrt{s} \) = 13 TeV with the ATLAS detector

Abstract This paper describes a search for events with one top-quark and large missing transverse momentum in the final state. Data collected during 2015 and 2016 by the ATLAS experiment from 13 TeV proton–proton collisions at the LHC corresponding to an integrated luminosity of 36.1 fb−1 are used. Two channels are considered, depending on the leptonic or the hadronic decays of...

Measurements of inclusive and differential fiducial cross-sections of \(t\bar{t}\gamma \) production in leptonic final states at \(\sqrt{s}=13~\text {TeV}\) in ATLAS

Inclusive and differential cross-sections for the production of a top-quark pair in association with a photon are measured with proton-proton collision data corresponding to an integrated luminosity of 36.1 \(\text{ fb }^{-1}\), collected by the ATLAS detector at the LHC in 2015 and 2016 at a centre-of-mass energy of 13 \(\text {TeV}\). The measurements are performed in single...

Measurement of the ratio of cross sections for inclusive isolated-photon production in pp collisions at \( \sqrt{s} \) = 13 and 8 TeV with the ATLAS detector

Abstract The ratio of the cross sections for inclusive isolated-photon production in pp collisions at centre-of-mass energies of 13 and 8 TeV is measured using the ATLAS detector at the LHC. The integrated luminosities of the 13 TeV and 8 TeV datasets are 3.2 fb−1 and 20.2 fb−1, respectively. The ratio is measured as a function of the photon transverse energy in different regions...

Search for Higgs boson pair production in the \( b\overline{b}W{W}^{*} \) decay mode at \( \sqrt{s} \) = 13 TeV with the ATLAS detector

Abstract A search for Higgs boson pair production in the \( b\overline{b}W{W}^{*} \) decay mode is performed in the \( b\overline{b}\mathit{\ell \nu qq} \) final state using 36.1 fb−1 of proton-proton collision data at a centre-of-mass energy of 13 TeV recorded with the ATLAS detector at the Large Hadron Collider. No evidence of events beyond the background expectation is found...

Measurement of the four-lepton invariant mass spectrum in 13 TeV proton-proton collisions with the ATLAS detector

Abstract A measurement of the four-lepton invariant mass spectrum is made with the ATLAS detector, using an integrated luminosity of 36.1 fb−1 of proton-proton collisions at \( \sqrt{s} \) = 13 TeV delivered by the Large Hadron Collider. The differential cross-section is measured for events containing two same-flavour opposite-sign lepton pairs. It exhibits a rich structure, with...

Measurements of inclusive and differential fiducial cross-sections of \( t\overline{t} \) production with additional heavy-flavour jets in proton-proton collisions at \( \sqrt{s} \) = 13 TeV with the ATLAS detector

Abstract This paper presents measurements of \( t\overline{t} \) production in association with additional b-jets in pp collisions at the LHC at a centre-of-mass energy of 13 TeV. The data were recorded with the ATLAS detector and correspond to an integrated luminosity of 36.1 fb−1. Fiducial cross-section measurements are performed in the dilepton and lepton-plus-jets \( t...

Measurement of the top quark mass in the \(t\bar{t}\rightarrow \) lepton+jets channel from \(\sqrt{s}=8\) TeV ATLAS data and combination with previous results

The top quark mass is measured using a template method in the \(t\bar{t} \rightarrow \mathrm {lepton+jets}\) channel (lepton is e or \(\mu \)) using ATLAS data recorded in 2012 at the LHC. The data were taken at a proton–proton centre-of-mass energy of \({\sqrt{s}} =8\) \(\text {TeV}\) and correspond to an integrated luminosity of \(20.2\)  fb\(^{-1}\). The \(t\bar{t} \rightarrow...

Measurement of the photon identification efficiencies with the ATLAS detector using LHC Run 2 data collected in 2015 and 2016

The efficiency of the photon identification criteria in the ATLAS detector is measured using \(36.1\hbox { fb}^1\) to \(36.7\hbox { fb}^1\) of pp collision data at \(\sqrt{s} = \hbox {13 TeV}\) collected in 2015 and 2016. The efficiencies are measured separately for converted and unconverted isolated photons, in four different pseudorapidity regions, for transverse momenta...

In situ calibration of large-radius jet energy and mass in 13 TeV proton–proton collisions with the ATLAS detector

The response of the ATLAS detector to large-radius jets is measured in situ using 36.2 fb\(^{-1}\) of \(\sqrt{s}=13\) TeV proton–proton collisions provided by the LHC and recorded by the ATLAS experiment during 2015 and 2016. The jet energy scale is measured in events where the jet recoils against a reference object, which can be either a calibrated photon, a reconstructed Z...

Measurements of W and Z boson production in pp collisions at \(\sqrt{s}=5.02\) TeV with the ATLAS detector

Measurements of fiducial integrated and differential cross sections for inclusive \(W^+\), \(W^-\) and Z boson production are reported. They are based on \(25.0 \pm 0.5\; \mathrm {pb}^{-1}\) of pp collision data at \(\sqrt{s} = 5.02\) TeV collected with the ATLAS detector at the CERN Large Hadron Collider. Electron and muon decay channels are analysed, and the combined \(W...

A strategy for a general search for new phenomena using data-derived signal regions and its application within the ATLAS experiment

This paper describes a strategy for a general search used by the ATLAS Collaboration to find potential indications of new physics. Events are classified according to their final state into many event classes. For each event class an automated search algorithm tests whether the data are compatible with the Monte Carlo simulated expectation in several distributions sensitive to the...

Search for doubly charged scalar bosons decaying into same-sign W boson pairs with the ATLAS detector

A search for doubly charged scalar bosons decaying into W boson pairs is presented. It uses a data sample from proton–proton collisions corresponding to an integrated luminosity of 36.1 fb\(^\mathrm {-1}\) collected by the ATLAS detector at the LHC at a centre-of-mass energy of 13 TeV in 2015 and 2016. This search is guided by a model that includes an extension of the Higgs...

Search for pair production of Higgs bosons in the \( b\overline{b}b\overline{b} \) final state using proton-proton collisions at \( \sqrt{s}=13 \) TeV with the ATLAS detector

Abstract A search for Higgs boson pair production in the \( b\overline{b}b\overline{b} \) final state is carried out with up to 36.1 fb−1 of LHC proton-proton collision data collected at \( \sqrt{s}=13 \) TeV with the ATLAS detector in 2015 and 2016. Three benchmark signals are studied: a spin-2 graviton decaying into a Higgs boson pair, a scalar resonance decaying into a Higgs...

Search for heavy Majorana or Dirac neutrinos and right-handed W gauge bosons in final states with two charged leptons and two jets at \( \sqrt{s}=13 \) TeV with the ATLAS detector

Abstract A search for heavy right-handed Majorana or Dirac neutrinos NR and heavy right-handed gauge bosons WR is performed in events with a pair of energetic electrons or muons, with the same or opposite electric charge, and two energetic jets. The events are selected from pp collision data with an integrated luminosity of 36.1 fb−1 collected by the ATLAS detector at \( \sqrt{s...

Search for Higgs boson pair production in the \(\gamma \gamma WW^*\) channel using \(pp\) collision data recorded at \(\sqrt{s}\) \(=13\) TeV with the ATLAS detector

Searches for non-resonant and resonant Higgs boson pair production are performed in the \(\gamma \gamma WW^*\) channel with the final state of \(\gamma \gamma \ell \nu jj\) using 36.1 \(\hbox {fb}^{-1}\) of proton–proton collision data recorded at a centre-of-mass energy of \(\sqrt{s}=\)13 TeV by the ATLAS detector at the Large Hadron Collider. No significant deviation from the...

Measurement of the azimuthal anisotropy of charged particles produced in \(\sqrt{s_{_\text {NN}}}\) = 5.02 TeV Pb+Pb collisions with the ATLAS detector

Measurements of the azimuthal anisotropy in lead–lead collisions at \(\sqrt{s_{_\text {NN}}}\) = 5.02 TeV are presented using a data sample corresponding to 0.49 \({\mathrm {nb}}^{-1}\) integrated luminosity collected by the ATLAS experiment at the LHC in 2015. The recorded minimum-bias sample is enhanced by triggers for “ultra-central” collisions, providing an opportunity to...

Search for new phenomena in events with same-charge leptons and b-jets in pp collisions at \( \sqrt{s}=13 \) TeV with the ATLAS detector

Abstract A search for new phenomena in events with two same-charge leptons or three leptons and jets identified as originating from b-quarks in a data sample of 36.1 fb−1 of pp collisions at \( \sqrt{s}=13 \) TeV recorded by the ATLAS detector at the Large Hadron Collider is reported. No significant excess is found and limits are set on vector-like quark, four-top-quark, and same...

Search for electroweak production of supersymmetric particles in final states with two or three leptons at \(\sqrt{s}=13\hbox {TeV}\) with the ATLAS detector

A search for the electroweak production of charginos, neutralinos and sleptons decaying into final states involving two or three electrons or muons is presented. The analysis is based on 36.1 fb\(^{-1}\) of \(\sqrt{s}=13\) TeV proton–proton collisions recorded by the ATLAS detector at the Large Hadron Collider. Several scenarios based on simplified models are considered. These...

Measurement of the \( Z\gamma \to \nu \overline{\nu}\gamma \) production cross section in pp collisions at \( \sqrt{s}=13 \) TeV with the ATLAS detector and limits on anomalous triple gauge-boson couplings

Abstract The production of Z bosons in association with a high-energy photon (Zγ production) is studied in the neutrino decay channel of the Z boson using pp collisions at \( \sqrt{s}=13 \) TeV. The analysis uses a data sample with an integrated luminosity of 36.1fb−1 collected by the ATLAS detector at the LHC in 2015 and 2016. Candidate Zγ events with invisible decays of the Z...