Alexander Ekman
Doctoral student
Publications
Displaying of publications. Sorted by year, then title.
Searches for New Physics Using Innovative Data Acquisition, Analysis, and Compression Techniques
Alexander Ekman
(2024)
DissertationSearch for the decay of the Higgs boson to a Z boson and a light pseudoscalar particle decaying to two photons
G. Aad, T.P.A. Åkesson, C. Doglioni, P.A. Ekman, V. Hedberg, et al.
(2024) Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 850
Journal articleElectron and photon energy calibration with the ATLAS detector using LHC Run 2 data
G Aad, Torsten Åkesson, Caterina Doglioni, Alexander Ekman, Vincent Hedberg, et al.
(2024) Journal of Instrumentation, 19
Journal articleProbing the CP nature of the top–Higgs Yukawa coupling in tt¯H and tH events with H→bb¯ decays using the ATLAS detector at the LHC
G. Aad, T.P.A. Åkesson, E.E. Corrigan, C. Doglioni, P.A. Ekman, et al.
(2024) Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 849
Journal articleMeasurement of the Centrality Dependence of the Dijet Yield in Formula Presented Collisions at Formula Presented with the ATLAS Detector
G. Aad, T.P.A. Åkesson, C. Doglioni, P.A. Ekman, V. Hedberg, et al.
(2024) Physical Review Letters, 132
Journal articleMeasurement of the production cross-section of J/ψ and ψ(2S) mesons in pp collisions at s=13 TeV with the ATLAS detector
G. Aad, T.P.A. Åkesson, C. Doglioni, P.A. Ekman, V. Hedberg, et al.
(2024) European Physical Journal C, 84
Journal articleSoftware Performance of the ATLAS Track Reconstruction for LHC Run 3
G. Aad, T.P.A. Åkesson, C. Doglioni, P.A. Ekman, V. Hedberg, et al.
(2024) Computing and Software for Big Science, 8
Journal articleStudy of High-Transverse-Momentum Higgs Boson Production in Association with a Vector Boson in the qqbb Final State with the ATLAS Detector
G. Aad, T.P.A. Åkesson, C. Doglioni, Alexander Ekman, V. Hedberg, et al.
(2024) Physical Review Letters, 132
Journal articleSearch for non-resonant Higgs boson pair production in the 2b+2ℓ+ETmiss final state in pp collisions at s = 13 TeV with the ATLAS detector
G. Aad, T.P.A. Åkesson, C. Doglioni, P.A. Ekman, V. Hedberg, et al.
(2024) Journal of High Energy Physics, 2024
Journal articleSearch for top-philic heavy resonances in pp collisions at s=13 TeV with the ATLAS detector
G. Aad, T.P.A. Åkesson, C. Doglioni, P.A. Ekman, V. Hedberg, et al.
(2024) European Physical Journal C, 84
Journal articleSearch for a CP-odd Higgs boson decaying into a heavy CP-even Higgs boson and a Z boson in the ℓ+ℓ−tt¯ and νν¯bb¯ final states using 140 fb−1 of data collected with the ATLAS detector
G. Aad, T.P.A. Åkesson, C. Doglioni, P.A. Ekman, V. Hedberg, et al.
(2024) Journal of High Energy Physics, 2024
Journal articleSearch for heavy resonances decaying into a Z or W boson and a Higgs boson in final states with leptons and b-jets in 139 fb−1 of pp collisions at √s = 13 TeV with the ATLAS detector
G. Aad, T.P.A. Åkesson, E.E. Corrigan, C. Doglioni, P.A. Ekman, et al.
(2023) Journal of High Energy Physics, 2023
Journal articleMeasurement of the nuclear modification factor of b-jets in 5.02 TeV Pb+Pb collisions with the ATLAS detector
G. Aad, T.P.A. Åkesson, E.E. Corrigan, C. Doglioni, P.A. Ekman, et al.
(2023) European Physical Journal C, 83
Journal articleMeasurement of exclusive pion pair production in proton–proton collisions at √s=7TeV with the ATLAS detector
G. Aad, T.P.A. Åkesson, E.E. Corrigan, C. Doglioni, P.A. Ekman, et al.
(2023) European Physical Journal C, 83
Journal articleCharged-hadron production in pp, p+Pb, Pb+Pb, and Xe+Xe collisions at √sNN = 5 TeV with the ATLAS detector at the LHC
G. Aad, T.P.A. Åkesson, C. Doglioni, P.A. Ekman, V. Hedberg, et al.
(2023) Journal of High Energy Physics, 2023
Journal articleMeasurement of single top-quark production in the s-channel in proton–proton collisions at √s = 13 TeV with the ATLAS detector
G. Aad, T.P.A. Åkesson, E.E. Corrigan, C. Doglioni, P.A. Ekman, et al.
(2023) Journal of High Energy Physics, 2023
Journal articleExclusive dielectron production in ultraperipheral Pb+Pb collisions at √sNN = 5.02 TeV with ATLAS
G. Aad, T.P.A. Åkesson, E.E. Corrigan, C. Doglioni, P.A. Ekman, et al.
(2023) Journal of High Energy Physics, 2023
Journal articleMeasurement of electroweak Z(νν¯) γjj production and limits on anomalous quartic gauge couplings in pp collisions at √s = 13 TeV with the ATLAS detector
G. Aad, T.P.A. Åkesson, E.E. Corrigan, C. Doglioni, P.A. Ekman, et al.
(2023) Journal of High Energy Physics, 2023
Journal articleSearch for Higgs boson pair production in association with a vector boson in pp collisions at √s=13TeV with the ATLAS detector
G. Aad, T.P.A. Åkesson, E.E. Corrigan, C. Doglioni, P.A. Ekman, et al.
(2023) European Physical Journal C, 83
Journal articleSearch for flavour-changing neutral current interactions of the top quark and the Higgs boson in events with a pair of τ-leptons in pp collisions at √s = 13 TeV with the ATLAS detector
G. Aad, T.P.A. Åkesson, E.E. Corrigan, C. Doglioni, P.A. Ekman, et al.
(2023) Journal of High Energy Physics, 2023
Journal articleConstraints on spin-0 dark matter mediators and invisible Higgs decays using ATLAS 13 TeV pp collision data with two top quarks and missing transverse momentum in the final state
G. Aad, T.P.A. Åkesson, E.E. Corrigan, C. Doglioni, P.A. Ekman, et al.
(2023) European Physical Journal C, 83
Journal articleMeasurement of the tt¯ production cross-section in pp collisions at √s = 5.02 TeV with the ATLAS detector
G. Aad, T.P.A. Åkesson, E.E. Corrigan, C. Doglioni, P.A. Ekman, et al.
(2023) Journal of High Energy Physics, 2023
Journal articleMeasurement of the total cross section and ρ -parameter from elastic scattering in pp collisions at √s=13 TeV with the ATLAS detector
G. Aad, T.P.A. Åkesson, E.E. Corrigan, C. Doglioni, P.A. Ekman, et al.
(2023) European Physical Journal C, 83
Journal articleSearch for dark matter produced in association with a dark Higgs boson decaying into W+ W− in the one-lepton final state at √s = 13 TeV using 139 fb −1 of pp collisions recorded with the ATLAS detector
G. Aad, T.P.A. Åkesson, E.E. Corrigan, C. Doglioni, P.A. Ekman, et al.
(2023) Journal of High Energy Physics, 2023
Journal articleSearch for dark photons from Higgs boson decays via ZH production with a photon plus missing transverse momentum signature from pp collisions at √s = 13 TeV with the ATLAS detector
G. Aad, T.P.A. Åkesson, E.E. Corrigan, C. Doglioni, P.A. Ekman, et al.
(2023) Journal of High Energy Physics, 2023
Journal articleSearch for leptonic charge asymmetry in tt¯ W production in final states with three leptons at √s = 13 TeV
G. Aad, T.P.A. Åkesson, E.E. Corrigan, C. Doglioni, P.A. Ekman, et al.
(2023) Journal of High Energy Physics, 2023
Journal articleDetermination of the strong coupling constant from transverse energy-energy correlations in multijet events at √s = 13 TeV with the ATLAS detector
G. Aad, T.P.A. Åkesson, C. Doglioni, P.A. Ekman, V. Hedberg, et al.
(2023) Journal of High Energy Physics, 2023
Journal articleMeasurements of Zγ+jets differential cross sections in pp collisions at √s = 13 TeV with the ATLAS detector
G. Aad, T.P.A. Åkesson, E.E. Corrigan, C. Doglioni, P.A. Ekman, et al.
(2023) Journal of High Energy Physics, 2023
Journal articleMeasurement of the properties of Higgs boson production at √s = 13 TeV in the H → γγ channel using 139 fb−1 of pp collision data with the ATLAS experiment
G. Aad, T.P.A. Åkesson, E.E. Corrigan, C. Doglioni, P.A. Ekman, et al.
(2023) Journal of High Energy Physics, 2023
Journal articleInclusive-photon production and its dependence on photon isolation in pp collisions at √s = 13 TeV using 139 fb −1 of ATLAS data
G. Aad, T.P.A. Åkesson, C. Doglioni, P.A. Ekman, V. Hedberg, et al.
(2023) Journal of High Energy Physics, 2023
Journal articleSearch for boosted diphoton resonances in the 10 to 70 GeV mass range using 138 fb −1 of 13 TeV pp collisions with the ATLAS detector
G. Aad, T.P.A. Åkesson, E.E. Corrigan, C. Doglioni, P.A. Ekman, et al.
(2023) Journal of High Energy Physics, 2023
Journal articleSearch for excited τ-leptons and leptoquarks in the final state with τ-leptons and jets in pp collisions at √s = 13 TeV with the ATLAS detector
G. Aad, T.P.A. Åkesson, C. Doglioni, P.A. Ekman, V. Hedberg, et al.
(2023) Journal of High Energy Physics, 2023
Journal articleSearch for a new Z′ gauge boson in 4μ events with the ATLAS experiment
G. Aad, T.P.A. Åkesson, E.E. Corrigan, C. Doglioni, P.A. Ekman, et al.
(2023) Journal of High Energy Physics, 2023
Journal articleInclusive and differential cross-sections for dilepton tt¯ production measured in √s = 13 TeV pp collisions with the ATLAS detector
G. Aad, T.P.A. Åkesson, E.E. Corrigan, C. Doglioni, P.A. Ekman, et al.
(2023) Journal of High Energy Physics, 2023
Journal articleSearch for direct pair production of sleptons and charginos decaying to two leptons and neutralinos with mass splittings near the W-boson mass in √s = 13 TeV pp collisions with the ATLAS detector
G. Aad, T.P.A. Åkesson, E.E. Corrigan, C. Doglioni, P.A. Ekman, et al.
(2023) Journal of High Energy Physics, 2023
Journal articleCross-section measurements for the production of a Z boson in association with high-transverse-momentum jets in pp collisions at √s = 13 TeV with the ATLAS detector
G. Aad, T.P.A. Åkesson, E.E. Corrigan, C. Doglioni, P.A. Ekman, et al.
(2023) Journal of High Energy Physics, 2023
Journal articleA search for new resonances in multiple final states with a high transverse momentum Z boson in √s = 13 TeV pp collisions with the ATLAS detector
G. Aad, T.P.A. Åkesson, E.E. Corrigan, C. Doglioni, P.A. Ekman, et al.
(2023) Journal of High Energy Physics, 2023
Journal articleSearch for tt¯ H/ A→ tt¯ tt¯ production in the multilepton final state in proton–proton collisions at √s = 13 TeV with the ATLAS detector
G. Aad, T.P.A. Åkesson, E.E. Corrigan, C. Doglioni, P.A. Ekman, et al.
(2023) Journal of High Energy Physics, 2023
Journal articleATLAS flavour-tagging algorithms for the LHC Run 2 pp collision dataset
G. Aad, T.P.A. Åkesson, E.E. Corrigan, C. Doglioni, P.A. Ekman, et al.
(2023) European Physical Journal C, 83
Journal articleMeasurements of W+W- production in decay topologies inspired by searches for electroweak supersymmetry
G. Aad, T.P.A. Åkesson, E.E. Corrigan, C. Doglioni, P.A. Ekman, et al.
(2023) European Physical Journal C, 83
Journal articleMeasurement of the polarisation of W bosons produced in top-quark decays using dilepton events at s=13 TeV with the ATLAS experiment
G. Aad, T.P.A. Åkesson, E.E. Corrigan, C. Doglioni, P.A. Ekman, et al.
(2023) Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 843
Journal articleObservation of gauge boson joint-polarisation states in W±Z production from pp collisions at s=13 TeV with the ATLAS detector
G. Aad, T.P.A. Åkesson, E.E. Corrigan, C. Doglioni, P.A. Ekman, et al.
(2023) Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 843
Journal articleSearch for an axion-like particle with forward proton scattering in association with photon pairs at ATLAS
G. Aad, T.P.A. Åkesson, C. Doglioni, P.A. Ekman, V. Hedberg, et al.
(2023) Journal of High Energy Physics, 2023
Journal articleSearch for pair-produced vector-like top and bottom partners in events with large missing transverse momentum in pp collisions with the ATLAS detector
G. Aad, T.P.A. Åkesson, E.E. Corrigan, C. Doglioni, P.A. Ekman, et al.
(2023) European Physical Journal C, 83
Journal articleSearch for pair-produced scalar and vector leptoquarks decaying into third-generation quarks and first- or second-generation leptons in pp collisions with the ATLAS detector
G. Aad, T.P.A. Åkesson, E.E. Corrigan, C. Doglioni, P.A. Ekman, et al.
(2023) Journal of High Energy Physics, 2023
Journal articleEvidence for the charge asymmetry in (Formula presented.) production at √s = 13 TeV with the ATLAS detector
G. Aad, T.P.A. Åkesson, E.E. Corrigan, C. Doglioni, P.A. Ekman, et al.
(2023) Journal of High Energy Physics, 2023
Journal articleTest of CP Invariance in Higgs Boson Vector-Boson-Fusion Production Using the H→γγ Channel with the ATLAS Detector
G. Aad, T.P.A. Åkesson, E.E. Corrigan, C. Doglioni, P.A. Ekman, et al.
(2023) Physical Review Letters, 131
Journal articleMeasurement of the charge asymmetry in top-quark pair production in association with a photon with the ATLAS experiment
G. Aad, T.P.A. Åkesson, E.E. Corrigan, C. Doglioni, P.A. Ekman, et al.
(2023) Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 843
Journal articleSearches for exclusive Higgs and Z boson decays into a vector quarkonium state and a photon using 139 fb - 1 of ATLAS √s=13 TeV proton–proton collision data
G. Aad, T.P.A. Åkesson, E.E. Corrigan, C. Doglioni, P.A. Ekman, et al.
(2023) European Physical Journal C, 83
Journal articleSearch for long-lived, massive particles in events with displaced vertices and multiple jets in pp collisions at √s = 13 TeV with the ATLAS detector
G. Aad, T.P.A. Åkesson, E.E. Corrigan, C. Doglioni, P.A. Ekman, et al.
(2023) Journal of High Energy Physics, 2023
Journal articleSearch for resonant WZ production in the fully leptonic final state in proton–proton collisions at √s=13 TeV with the ATLAS detector
G. Aad, T.P.A. Åkesson, E.E. Corrigan, C. Doglioni, P.A. Ekman, et al.
(2023) European Physical Journal C, 83
Journal articleMeasurement of substructure-dependent jet suppression in Pb+Pb collisions at 5.02 TeV with the ATLAS detector
G. Aad, T.P.A. Åkesson, E.E. Corrigan, C. Doglioni, P.A. Ekman, et al.
(2023) Physical Review C, 107
Journal articleSearches for lepton-flavour-violating decays of the Higgs boson into eτ and μτ in √s = 13 TeV pp collisions with the ATLAS detector
G. Aad, T.P.A. Åkesson, E.E. Corrigan, C. Doglioni, P.A. Ekman, et al.
(2023) Journal of High Energy Physics, 2023
Journal articleMeasurements of observables sensitive to colour reconnection in tt¯ events with the ATLAS detector at √s= 13 TeV
G. Aad, T.P.A. Åkesson, E.E. Corrigan, C. Doglioni, P.A. Ekman, et al.
(2023) European Physical Journal C, 83
Journal articleMeasurement of Zγγ production in pp collisions at √s=13 TeV with the ATLAS detector
G. Aad, T.P.A. Åkesson, E.E. Corrigan, C. Doglioni, P.A. Ekman, et al.
(2023) European Physical Journal C, 83
Journal articleMeasurement of the Higgs boson mass in the H → ZZ⁎ → 4ℓ decay channel using 139 fb−1 of s=13 TeV pp collisions recorded by the ATLAS detector at the LHC
G. Aad, T.P.A. Åkesson, E.E. Corrigan, C. Doglioni, P.A. Ekman, et al.
(2023) Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 843
Journal articleSearch for third-generation vector-like leptons in pp collisions at √s = 13 TeV with the ATLAS detector
G. Aad, T.P.A. Åkesson, E.E. Corrigan, C. Doglioni, P.A. Ekman, et al.
(2023) Journal of High Energy Physics, 2023
Journal articleCalibration of the light-flavour jet mistagging efficiency of the b-tagging algorithms with Z+jets events using 139 fb - 1 of ATLAS proton–proton collision data at √s=13 TeV
G. Aad, T.P.A. Åkesson, E.E. Corrigan, C. Doglioni, P.A. Ekman, et al.
(2023) European Physical Journal C, 83
Journal articleSearch for new phenomena in multi-body invariant masses in events with at least one isolated lepton and two jets using √s = 13 TeV proton–proton collision data collected by the ATLAS detector
G. Aad, T.P.A. Åkesson, E.E. Corrigan, C. Doglioni, P.A. Ekman, et al.
(2023) Journal of High Energy Physics, 2023
Journal articleStrong Constraints on Jet Quenching in Centrality-Dependent p+Pb Collisions at 5.02 TeV from ATLAS
G. Aad, T.P.A. Åkesson, E.E. Corrigan, C. Doglioni, P.A. Ekman, et al.
(2023) Physical Review Letters, 131
Journal articleObservation of the γγ→ττ Process in Pb+Pb Collisions and Constraints on the τ-Lepton Anomalous Magnetic Moment with the ATLAS Detector
G. Aad, T.P.A. Åkesson, E.E. Corrigan, C. Doglioni, P.A. Ekman, et al.
(2023) Physical Review Letters, 131
Journal articleMeasurements of the suppression and correlations of dijets in Xe+Xe collisions at Formula Presented TeV
G. Aad, T.P.A. Åkesson, C. Doglioni, P.A. Ekman, V. Hedberg, et al.
(2023) Physical Review C, 108
Journal articleComparison of inclusive and photon-tagged jet suppression in 5.02 TeV Pb+Pb collisions with ATLAS
G. Aad, T.P.A. Åkesson, C. Doglioni, P.A. Ekman, V. Hedberg, et al.
(2023) Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 846
Journal articleMeasurements of Higgs boson production by gluon-gluon fusion and vector-boson fusion using H→WW*→eνμν decays in pp collisions at Formula Presented with the ATLAS detector
G. Aad, T.P.A. Åkesson, E.E. Corrigan, C. Doglioni, P.A. Ekman, et al.
(2023) Physical Review D, 108
Journal articleObservation of an Excess of Dicharmonium Events in the Four-Muon Final State with the ATLAS Detector
G. Aad, T.P.A. Åkesson, C. Doglioni, P.A. Ekman, V. Hedberg, et al.
(2023) Physical Review Letters, 131
Journal articleSearch for leptoquarks decaying into the bτ final state in pp collisions at √s = 13 TeV with the ATLAS detector
G. Aad, T.P.A. Åkesson, C. Doglioni, P.A. Ekman, V. Hedberg, et al.
(2023) Journal of High Energy Physics, 2023
Journal articleLuminosity determination in pp collisions at √s=13 TeV using the ATLAS detector at the LHC
G. Aad, T.P.A. Åkesson, C. Doglioni, P.A. Ekman, V. Hedberg, et al.
(2023) European Physical Journal C, 83
Journal articleSearch for lepton-flavour violation in high-mass dilepton final states using 139 fb −1 of pp collisions at √s = 13 TeV with the ATLAS detector
G. Aad, T.P.A. Åkesson, C. Doglioni, P.A. Ekman, V. Hedberg, et al.
(2023) Journal of High Energy Physics, 2023
Journal articleMeasurement of the Sensitivity of Two-Particle Correlations in pp Collisions to the Presence of Hard Scatterings
G. Aad, T.P.A. Åkesson, Caterina Doglioni, Alexander Ekman, Vincent Hedberg, et al.
(2023) Physical Review Letters, 131
Journal articleSearch for pairs of muons with small displacements in pp collisions at s=13 TeV with the ATLAS detector
G. Aad, T.P.A. Åkesson, C. Doglioni, P.A. Ekman, V. Hedberg, et al.
(2023) Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 846
Journal articleMeasurement of the cross-sections of the electroweak and total production of a Zγ pair in association with two jets in pp collisions at s=13 TeV with the ATLAS detector
G. Aad, T.P.A. Åkesson, C. Doglioni, P.A. Ekman, V. Hedberg, et al.
(2023) Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 846
Journal articleAnomaly detection search for new resonances decaying into a Higgs boson and a generic new particle X in hadronic final states using Formula Presented pp collisions with the ATLAS detector
G. Aad, T.P.A. Åkesson, E.E. Corrigan, C. Doglioni, P.A. Ekman, et al.
(2023) Physical Review D, 108
Journal articleObservation of Single-Top-Quark Production in Association with a Photon Using the ATLAS Detector
G. Aad, T.P.A. Åkesson, Eric Edward Corrigan, Caterina Doglioni, Alexander Ekman, et al.
(2023) Physical Review Letters, 131
Journal articleSearch for a new scalar resonance in flavour-changing neutral-current top-quark decays t → qX (q = u, c), with X → bb¯ , in proton-proton collisions at √s = 13 TeV with the ATLAS detector
G. Aad, T.P.A. Åkesson, E.E. Corrigan, C. Doglioni, P.A. Ekman, et al.
(2023) Journal of High Energy Physics, 2023
Journal articleEvidence of off-shell Higgs boson production from ZZ leptonic decay channels and constraints on its total width with the ATLAS detector
G. Aad, T.P.A. Åkesson, C. Doglioni, P.A. Ekman, V. Hedberg, et al.
(2023) Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 846
Journal articleSearch for periodic signals in the dielectron and diphoton invariant mass spectra using 139 fb−1 of pp collisions at √s = 13 TeV with the ATLAS detector
G. Aad, T.P.A. Åkesson, C. Doglioni, P.A. Ekman, V. Hedberg, et al.
(2023) Journal of High Energy Physics, 2023
Journal articleSearch for nonresonant pair production of Higgs bosons in the Formula Presented final state in pp collisions at Formula Presented with the ATLAS detector
M. Amerl, T.P.A. Åkesson, C. Doglioni, P.A. Ekman, V. Hedberg, et al.
(2023) Physical Review D, 108
Journal articleSearch for Majorana neutrinos in same-sign WW scattering events from pp collisions at √s=13 TeV
G. Aad, T.P.A. Åkesson, C. Doglioni, P.A. Ekman, V. Hedberg, et al.
(2023) European Physical Journal C, 83
Journal articleSearch for Dark Photons in Rare Z Boson Decays with the ATLAS Detector
G. Aad, T.P.A. Åkesson, C. Doglioni, P.A. Ekman, V. Hedberg, et al.
(2023) Physical Review Letters, 131
Journal articleIntegrated and differential fiducial cross-section measurements for the vector boson fusion production of the Higgs boson in the H →WW∗→eνμν decay channel at 13 TeV with the ATLAS detector
G Aad, Torsten Åkesson, Caterina Doglioni, Alexander Ekman, Vincent Hedberg, et al.
(2023) Physical Review D, 108
Journal articleMeasurement of Suppression of Large-Radius Jets and Its Dependence on Substructure in Pb+Pb Collisions at √sNN=5.02 TeV with the ATLAS Detector
G Aad, Torsten Åkesson, Caterina Doglioni, Alexander Ekman, Vincent Hedberg, et al.
(2023) Physical Review Letters, 131
Journal article