Eur Phys J C Part Fields
May 2016
This paper presents a new method of reconstructing the individual charged and neutral hadrons in tau decays with the ATLAS detector. The reconstructed hadrons are used to classify the decay mode and to calculate the visible four-momentum of reconstructed tau candidates, significantly improving the resolution with respect to the calibration in the existing tau reconstruction. The performance of the reconstruction algorithm is optimised and evaluated using simulation and validated using samples of [Formula: see text] and [Formula: see text]+jets events selected from proton-proton collisions at a centre-of-mass energy [Formula: see text], corresponding to an integrated luminosity of 5 [Formula: see text].
View Article and Find Full Text PDFEur Phys J C Part Fields
May 2016
This article documents the performance of the ATLAS muon identification and reconstruction using the LHC dataset recorded at [Formula: see text] TeV in 2015. Using a large sample of [Formula: see text] and [Formula: see text] decays from 3.2 fb[Formula: see text] of collision data, measurements of the reconstruction efficiency, as well as of the momentum scale and resolution, are presented and compared to Monte Carlo simulations.
View Article and Find Full Text PDFDistributions of transverse momentum [Formula: see text] and the related angular variable [Formula: see text] of Drell–Yan lepton pairs are measured in 20.3 fb[Formula: see text] of proton–proton collisions at [Formula: see text] TeV with the ATLAS detector at the LHC. Measurements in electron-pair and muon-pair final states are corrected for detector effects and combined.
View Article and Find Full Text PDFThe production rates of prompt and non-prompt [Formula: see text] and [Formula: see text] mesons in their dimuon decay modes are measured using 2.1 and 11.4 fb[Formula: see text] of data collected with the ATLAS experiment at the Large Hadron Collider, in proton-proton collisions at [Formula: see text] and 8 respectively.
View Article and Find Full Text PDFA search for strongly produced supersymmetric particles is conducted using signatures involving multiple energetic jets and either two isolated leptons ( or [Formula: see text]) with the same electric charge or at least three isolated leptons. The search also utilises -tagged jets, missing transverse momentum and other observables to extend its sensitivity. The analysis uses a data sample of proton-proton collisions at [Formula: see text] TeV recorded with the ATLAS detector at the Large Hadron Collider in 2015 corresponding to a total integrated luminosity of 3.
View Article and Find Full Text PDFEur Phys J C Part Fields
April 2016
A search for a massive resonance [Formula: see text]decaying into a W and a Higgs boson in the [Formula: see text] ([Formula: see text], [Formula: see text]) final state is presented. Results are based on data corresponding to an integrated luminosity of 19.7[Formula: see text] of proton-proton collisions at [Formula: see text] [Formula: see text], collected using the CMS detector at the LHC.
View Article and Find Full Text PDFEur Phys J C Part Fields
April 2016
This article presents the sensitivity of the ATLAS experiment to the lepton-flavour-violating decays of [Formula: see text]. A method utilising the production of [Formula: see text] leptons via [Formula: see text] decays is used. This method is applied to the sample of 20.
View Article and Find Full Text PDFEur Phys J C Part Fields
December 2015
A search is performed for heavy long-lived charged particles using 3.0 [Formula: see text] of proton-proton collisions collected at [Formula: see text][Formula: see text] 7 and 8 TeV with the LHCb detector. The search is mainly based on the response of the ring imaging Cherenkov detectors to distinguish the heavy, slow-moving particles from muons.
View Article and Find Full Text PDFEur Phys J C Part Fields
January 2015
The jet energy scale (JES) and its systematic uncertainty are determined for jets measured with the ATLAS detector using proton-proton collision data with a centre-of-mass energy of [Formula: see text] TeV corresponding to an integrated luminosity of [Formula: see text][Formula: see text]. Jets are reconstructed from energy deposits forming topological clusters of calorimeter cells using the anti-[Formula: see text] algorithm with distance parameters [Formula: see text] or [Formula: see text], and are calibrated using MC simulations. A residual JES correction is applied to account for differences between data and MC simulations.
View Article and Find Full Text PDFEur Phys J C Part Fields
November 2015
Measurements of the [Formula: see text][Formula: see text] production cross sections in proton-proton collisions at center-of-mass energies of 7 and 8[Formula: see text] are presented. Candidate events for the leptonic decay mode [Formula: see text], where [Formula: see text] denotes an electron or a muon, are reconstructed and selected from data corresponding to an integrated luminosity of 5.1 (19.
View Article and Find Full Text PDFEur Phys J C Part Fields
October 2015
This paper reviews and extends searches for the direct pair production of the scalar supersymmetric partners of the top and bottom quarks in proton-proton collisions collected by the ATLAS collaboration during the LHC Run 1. Most of the analyses use 20 [Formula: see text] of collisions at a centre-of-mass energy of [Formula: see text] TeV, although in some case an additional [Formula: see text] of collision data at [Formula: see text] TeV are used. New analyses are introduced to improve the sensitivity to specific regions of the model parameter space.
View Article and Find Full Text PDFEur Phys J C Part Fields
September 2015
Many extensions of the Standard Model predict the existence of charged heavy long-lived particles, such as -hadrons or charginos. These particles, if produced at the Large Hadron Collider, should be moving non-relativistically and are therefore identifiable through the measurement of an anomalously large specific energy loss in the ATLAS pixel detector. Measuring heavy long-lived particles through their track parameters in the vicinity of the interaction vertex provides sensitivity to metastable particles with lifetimes from 0.
View Article and Find Full Text PDFEur Phys J C Part Fields
October 2015
Studies of the spin, parity and tensor couplings of the Higgs boson in the [Formula: see text], [Formula: see text] and [Formula: see text] decay processes at the LHC are presented. The investigations are based on [Formula: see text] of collision data collected by the ATLAS experiment at [Formula: see text] TeV and [Formula: see text] TeV. The Standard Model (SM) Higgs boson hypothesis, corresponding to the quantum numbers [Formula: see text], is tested against several alternative spin scenarios, including non-SM spin-0 and spin-2 models with universal and non-universal couplings to fermions and vector bosons.
View Article and Find Full Text PDFThe paper presents studies of Bose-Einstein Correlations (BEC) for pairs of like-sign charged particles measured in the kinematic range [Formula: see text] 100 MeV and [Formula: see text] 2.5 in proton collisions at centre-of-mass energies of 0.9 and 7 TeV with the ATLAS detector at the CERN Large Hadron Collider.
View Article and Find Full Text PDFA search for Higgs boson pair production [Formula: see text] is performed with 19.5 fb[Formula: see text] of proton-proton collision data at [Formula: see text] TeV, which were recorded by the ATLAS detector at the Large Hadron Collider in 2012. The decay products of each Higgs boson are reconstructed as a high-momentum [Formula: see text] system with either a pair of small-radius jets or a single large-radius jet, the latter exploiting jet substructure techniques and associated -tagged track-jets.
View Article and Find Full Text PDFEur Phys J C Part Fields
August 2015
A search for heavy long-lived multi-charged particles is performed using the ATLAS detector at the LHC. Data collected in 2012 at [Formula: see text] TeV from collisions corresponding to an integrated luminosity of 20.3 fb[Formula: see text]are examined.
View Article and Find Full Text PDFA search for the Standard Model Higgs boson produced in association with a top-quark pair, [Formula: see text], is presented. The analysis uses 20.3 fb of collision data at [Formula: see text], collected with the ATLAS detector at the Large Hadron Collider during 2012.
View Article and Find Full Text PDFA search for Higgs boson decays to invisible particles is performed using 20.3 [Formula: see text] of collision data at a centre-of-mass energy of 8 TeV recorded by the ATLAS detector at the Large Hadron Collider. The process considered is Higgs boson production in association with a vector boson ([Formula: see text] or ) that decays hadronically, resulting in events with two or more jets and large missing transverse momentum.
View Article and Find Full Text PDFEur Phys J C Part Fields
July 2015
Measurements of the and final states in the mass range above the [Formula: see text] and [Formula: see text] thresholds provide a unique opportunity to measure the off-shell coupling strength of the Higgs boson. This paper presents constraints on the off-shell Higgs boson event yields normalised to the Standard Model prediction (signal strength) in the [Formula: see text], [Formula: see text] and [Formula: see text] final states. The result is based on collision data collected by the ATLAS experiment at the LHC, corresponding to an integrated luminosity of 20.
View Article and Find Full Text PDFStringent limits are set on the long-lived lepton-like sector of the phenomenological minimal supersymmetric standard model (pMSSM) and the anomaly-mediated supersymmetry breaking (AMSB) model. The limits are derived from the results presented in a recent search for long-lived charged particles in proton-proton collisions, based on data collected by the CMS detector at a centre-of-mass energy of 8 TeV at the Large Hadron Collider. In the pMSSM parameter sub-space considered, 95.
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