Search for resonances decaying into photon pairs in 139 fb−1 of pp collisions at √s = 13 TeV with the ATLAS detector

open32siSearches for new resonances in the diphoton final state, with spin 0 as predicted by theories with an extended Higgs sector and with spin 2 using a warped extra-dimension benchmark model, are presented using 139 fb−1 of √s = 13 TeV pp collision data collected by the ATLAS experiment at the LHC. No significant deviation from the Standard Model is observed and upper limits are placed on the production cross-section times branching ratio to two photons as a function of the resonance mass.openDe Castro , S. ; Fabbri , L. ; Gabrielli , A. ; Rinaldi , L. ; Semprini Cesari , N. ; Sioli , M. ; Villa , M. ; Zoccoli , A. ; Bellagamba , L. ; Boscherini , D. ; Bruni , A.. ; Bruni , G. ; Giacobbe , B. ; Polini , A. ; Sbarra , C. ; Sidoti , A. ; Franchini , M. ; Romano , M. ; Valentinetti , S. ; Alberghi , G. L. ; Lasagni Manghi , F; Massa , L. ; Vittori , C. ; Alfonsi , F: ; Cabras , G. ; Cervelli , A. ; Negrini , M. ; Todome , K. ; Carratta , G. ; Cavalli , N. ; Clissa , L. ; ATLAS collaborationDe Castro , S. ; Fabbri , L. ; Gabrielli , A. ; Rinaldi , L. ; Semprini Cesari , N. ; Sioli , M. ; Villa , M. ; Zoccoli , A. ; Bellagamba , L. ; Boscherini , D. ; Bruni , A. ; Bruni , G. ; Giacobbe , B. ; Polini , A. ; Sbarra , C. ; Sidoti , A. ; Franchini , M. ; Romano , M. ; Valentinetti , S. ; Alberghi , G. L. ; Lasagni Manghi , F; Massa , L. ; Vittori , C. ; Alfonsi , F: ; Cabras , G. ; Cervelli , A. ; Negrini , M. ; Todome , K. ; Carratta , G. ; Cavalli , N. ; Clissa , L. ; ATLAS collaboratio

Search for Dark Matter Produced in Association with a Dark Higgs Boson Decaying into W±W∓ or ZZ in Fully Hadronic Final States from √s=13 TeV pp Collisions Recorded with the ATLAS Detector

open32siSeveral extensions of the Standard Model predict the production of dark matter particles at the LHC. An uncharted signature of dark matter particles produced in association with VV ¼ WW∓ or ZZ pairs from a decay of a dark Higgs boson s is searched for using 139 fb−1 of pp collisions recorded by the ATLAS detector at a center-of-mass energy of 13 TeV. The s → Vðqq¯ÞVðqq¯Þ decays are reconstructed with a novel technique aimed at resolving the dense topology from boosted VV pairs using jets in the calorimeter and tracking information. Dark Higgs scenarios with ms > 160 GeV are excluded.openDe Castro , S. ; Fabbri , L. ; Gabrielli , A. ; Rinaldi , L. ; Semprini Cesari , N. ; Sioli , M. ; Villa , M. ; Zoccoli , A. ; Bellagamba , L. ; Boscherini , D. ; Bruni , A.. ; Bruni , G. ; Giacobbe , B. ; Polini , A. ; Sbarra , C. ; Sidoti , A. ; Franchini , M. ; Romano , M. ; Valentinetti , S. ; Alberghi , G. L. ; Lasagni Manghi , F; Massa , L. ; Vittori , C. ; Alfonsi , F: ; Cabras , G. ; Cervelli , A. ; Negrini , M. ; Todome , K. ; Carratta , G. ; Cavalli , N. ; Clissa , L. ; ATLAS collaborationDe Castro , S. ; Fabbri , L. ; Gabrielli , A. ; Rinaldi , L. ; Semprini Cesari , N. ; Sioli , M. ; Villa , M. ; Zoccoli , A. ; Bellagamba , L. ; Boscherini , D. ; Bruni , A. ; Bruni , G. ; Giacobbe , B. ; Polini , A. ; Sbarra , C. ; Sidoti , A. ; Franchini , M. ; Romano , M. ; Valentinetti , S. ; Alberghi , G. L. ; Lasagni Manghi , F; Massa , L. ; Vittori , C. ; Alfonsi , F: ; Cabras , G. ; Cervelli , A. ; Negrini , M. ; Todome , K. ; Carratta , G. ; Cavalli , N. ; Clissa , L. ; ATLAS collaboratio

Performance of the ATLAS Level-1 topological trigger in Run 2

open32siDuring LHC Run 2 (2015–2018) the ATLAS Level-1 topological trigger allowed efficient data-taking by the ATLAS experiment at luminosities up to 2.1×1034 cm−2s−1, which exceeds the design value by a factor of two. The system was installed in 2016 and operated in 2017 and 2018. It uses Field Programmable Gate Array processors to select interesting events by placing kinematic and angular requirements on electromagnetic clusters, jets, τ -leptons, muons and the missing transverse energy. It allowed to significantly improve the background event rejection and signal event acceptance, in particular for Higgs and B-physics processes.openDe Castro , S. ; Fabbri , L. ; Gabrielli , A. ; Rinaldi , L. ; Semprini Cesari , N. ; Sioli , M. ; Villa , M. ; Zoccoli , A. ; Bellagamba , L. ; Boscherini , D. ; Bruni , A.. ; Bruni , G. ; Giacobbe , B. ; Polini , A. ; Sbarra , C. ; Sidoti , A. ; Franchini , M. ; Romano , M. ; Valentinetti , S. ; Alberghi , G. L. ; Lasagni Manghi , F; Massa , L. ; Vittori , C. ; Alfonsi , F: ; Cabras , G. ; Cervelli , A. ; Negrini , M. ; Todome , K. ; Carratta , G. ; Cavalli , N. ; Clissa , L. ; ATLAS collaborationDe Castro , S. ; Fabbri , L. ; Gabrielli , A. ; Rinaldi , L. ; Semprini Cesari , N. ; Sioli , M. ; Villa , M. ; Zoccoli , A. ; Bellagamba , L. ; Boscherini , D. ; Bruni , A. ; Bruni , G. ; Giacobbe , B. ; Polini , A. ; Sbarra , C. ; Sidoti , A. ; Franchini , M. ; Romano , M. ; Valentinetti , S. ; Alberghi , G. L. ; Lasagni Manghi , F; Massa , L. ; Vittori , C. ; Alfonsi , F: ; Cabras , G. ; Cervelli , A. ; Negrini , M. ; Todome , K. ; Carratta , G. ; Cavalli , N. ; Clissa , L. ; ATLAS collaboratio

Preparing Distributed Computing Operations for the HL-LHC Era With Operational Intelligence

open26siAs a joint effort from various communities involved in the Worldwide LHC Computing Grid, the Operational Intelligence project aims at increasing the level of automation in computing operations and reducing human interventions. The distributed computing systems currently deployed by the LHC experiments have proven to be mature and capable of meeting the experimental goals, by allowing timely delivery of scientific results. However, a substantial number of interventions from software developers, shifters, and operational teams is needed to efficiently manage such heterogenous infrastructures. Under the scope of the Operational Intelligence project, experts from several areas have gathered to propose and work on “smart” solutions. Machine learning, data mining, log analysis, and anomaly detection are only some of the tools we have evaluated for our use cases. In this community study contribution, we report on the development of a suite of operational intelligence services to cover various use cases: workload management, data management, and site operations.openDi Girolamo A.; Legger F.; Paparrigopoulos P.; Schovancova J.; Beermann T.; Boehler M.; Bonacorsi D.; Clissa L.; Decker de Sousa L.; Diotalevi T.; Giommi L.; Grigorieva M.; Giordano D.; Hohn D.; Javurek T.; Jezequel S.; Kuznetsov V.; Lassnig M.; Mageirakos V.; Olocco M.; Padolski S.; Paltenghi M.; Rinaldi L.; Sharma M.; Tisbeni S.R.; Tuckus N.Di Girolamo A.; Legger F.; Paparrigopoulos P.; Schovancova J.; Beermann T.; Boehler M.; Bonacorsi D.; Clissa L.; Decker de Sousa L.; Diotalevi T.; Giommi L.; Grigorieva M.; Giordano D.; Hohn D.; Javurek T.; Jezequel S.; Kuznetsov V.; Lassnig M.; Mageirakos V.; Olocco M.; Padolski S.; Paltenghi M.; Rinaldi L.; Sharma M.; Tisbeni S.R.; Tuckus N

Search for dark matter in events with missing transverse momentum and a Higgs boson decaying into two photons in pp collisions at √s = 13 TeV with the ATLAS detector

open32siA search for dark-matter particles in events with large missing transverse momentum and a Higgs boson candidate decaying into two photons is reported. The search uses 139 fb−1 of proton-proton collision data collected at √ s = 13 TeV with the ATLAS detector at the CERN LHC between 2015 and 2018. No significant excess of events over the Standard Model predictions is observed. The results are interpreted by extracting limits on three simplified models that include either vector or pseudoscalar mediators and predict a final state with a pair of dark-matter candidates and a Higgs boson decaying into two photons.openDe Castro , S. ; Fabbri , L. ; Gabrielli , A. ; Rinaldi , L. ; Semprini Cesari , N. ; Sioli , M. ; Villa , M. ; Zoccoli , A. ; Bellagamba , L. ; Boscherini , D. ; Bruni , A.. ; Bruni , G. ; Giacobbe , B. ; Polini , A. ; Sbarra , C. ; Sidoti , A. ; Franchini , M. ; Romano , M. ; Valentinetti , S. ; Alberghi , G. L. ; Lasagni Manghi , F; Massa , L. ; Vittori , C. ; Alfonsi , F: ; Cabras , G. ; Cervelli , A. ; Negrini , M. ; Todome , K. ; Carratta , G. ; Cavalli , N. ; Clissa , L. ; ATLAS collaborationDe Castro , S. ; Fabbri , L. ; Gabrielli , A. ; Rinaldi , L. ; Semprini Cesari , N. ; Sioli , M. ; Villa , M. ; Zoccoli , A. ; Bellagamba , L. ; Boscherini , D. ; Bruni , A. ; Bruni , G. ; Giacobbe , B. ; Polini , A. ; Sbarra , C. ; Sidoti , A. ; Franchini , M. ; Romano , M. ; Valentinetti , S. ; Alberghi , G. L. ; Lasagni Manghi , F; Massa , L. ; Vittori , C. ; Alfonsi , F: ; Cabras , G. ; Cervelli , A. ; Negrini , M. ; Todome , K. ; Carratta , G. ; Cavalli , N. ; Clissa , L. ; ATLAS collaboratio

Measurements of Higgs bosons decaying to bottom quarks from vector boson fusion production with the ATLAS experiment at √s=13TeV

open32siThe paper presents a measurement of the Standard Model Higgs Boson decaying to b-quark pairs in the vector boson fusion (VBF) production mode. A sample corresponding to 126 fb−1 of √s = 13 TeV proton–proton collision data, collected with the ATLAS experiment at the Large Hadron Collider, is analyzed utilizing an adversarial neural network for event classification. The signal strength, defined as the ratio of the measured signal yield to that predicted by the Standard Model for VBF Higgs production, is measured to be 0.95+0.38 −0.36 , corresponding to an observed (expected) significance of 2.6 (2.8) standard deviations from the background only hypothesis. The results are additionally combined with an analysis of Higgs bosons decaying to b-quarks, produced via VBF in association with a photon.openDe Castro , S. ; Fabbri , L. ; Gabrielli , A. ; Rinaldi , L. ; Semprini Cesari , N. ; Sioli , M. ; Villa , M. ; Zoccoli , A. ; Bellagamba , L. ; Boscherini , D. ; Bruni , A.. ; Bruni , G. ; Giacobbe , B. ; Polini , A. ; Sbarra , C. ; Sidoti , A. ; Franchini , M. ; Romano , M. ; Valentinetti , S. ; Alberghi , G. L. ; Lasagni Manghi , F; Massa , L. ; Vittori , C. ; Alfonsi , F: ; Cabras , G. ; Cervelli , A. ; Negrini , M. ; Todome , K. ; Carratta , G. ; Cavalli , N. ; Clissa , L. ; ATLAS collaborationDe Castro , S. ; Fabbri , L. ; Gabrielli , A. ; Rinaldi , L. ; Semprini Cesari , N. ; Sioli , M. ; Villa , M. ; Zoccoli , A. ; Bellagamba , L. ; Boscherini , D. ; Bruni , A. ; Bruni , G. ; Giacobbe , B. ; Polini , A. ; Sbarra , C. ; Sidoti , A. ; Franchini , M. ; Romano , M. ; Valentinetti , S. ; Alberghi , G. L. ; Lasagni Manghi , F; Massa , L. ; Vittori , C. ; Alfonsi , F: ; Cabras , G. ; Cervelli , A. ; Negrini , M. ; Todome , K. ; Carratta , G. ; Cavalli , N. ; Clissa , L. ; ATLAS collaboratio

Search for Higgs boson production in association with a high-energy photon via vector-boson fusion with decay into bottom quark pairs at √ s= 13 TeV with the ATLAS detector

open32siA search is presented for the production of the Standard Model Higgs boson in association with a high-energy photon. With a focus on the vector-boson fusion process and the dominant Higgs boson decay into b-quark pairs, the search benefits from a large reduction of multijet background compared to more inclusive searches. Results are reported from the analysis of 132 fb−1 of pp collision data at √s = 13 TeV collected with the ATLAS detector at the LHC. The measured Higgs boson signal yield in this final-state signature is 1.3 ± 1.0 times the Standard Model prediction. The observed significance of the Higgs boson signal above the background is 1.3 standard deviations, compared to an expected significance of 1.0 standard deviations.openDe Castro , S. ; Fabbri , L. ; Gabrielli , A. ; Rinaldi , L. ; Semprini Cesari , N. ; Sioli , M. ; Villa , M. ; Zoccoli , A. ; Bellagamba , L. ; Boscherini , D. ; Bruni , A.. ; Bruni , G. ; Giacobbe , B. ; Polini , A. ; Sbarra , C. ; Sidoti , A. ; Franchini , M. ; Romano , M. ; Valentinetti , S. ; Alberghi , G. L. ; Lasagni Manghi , F; Massa , L. ; Vittori , C. ; Alfonsi , F: ; Cabras , G. ; Cervelli , A. ; Negrini , M. ; Todome , K. ; Carratta , G. ; Cavalli , N. ; Clissa , L. ; ATLAS collaborationDe Castro , S. ; Fabbri , L. ; Gabrielli , A. ; Rinaldi , L. ; Semprini Cesari , N. ; Sioli , M. ; Villa , M. ; Zoccoli , A. ; Bellagamba , L. ; Boscherini , D. ; Bruni , A. ; Bruni , G. ; Giacobbe , B. ; Polini , A. ; Sbarra , C. ; Sidoti , A. ; Franchini , M. ; Romano , M. ; Valentinetti , S. ; Alberghi , G. L. ; Lasagni Manghi , F; Massa , L. ; Vittori , C. ; Alfonsi , F: ; Cabras , G. ; Cervelli , A. ; Negrini , M. ; Todome , K. ; Carratta , G. ; Cavalli , N. ; Clissa , L. ; ATLAS collaboratio

Search for type-III seesaw heavy leptons in dilepton final states in pp collisions at √s=13TeV with the ATLAS detector

open32siA search for the pair production of heavy leptons as predicted by the type-III seesaw mechanism is presented. The search uses proton–proton collision data at a centre-of-mass energy of 13 TeV, corresponding to 139 fb−1 of integrated luminosity recorded by the ATLAS detector during Run 2 of the Large Hadron Collider. The analysis focuses on the final state with two light leptons (electrons or muons) of different flavour and charge combinations, with at least two jets and large missing transverse momentum. No significant excess over the Standard Model expectation is observed. The results are translated into exclusion limits on heavy-lepton masses, and the observed lower limit on the mass of the type-III seesaw heavy leptons is 790 GeV at 95% confidence level.openDe Castro , S. ; Fabbri , L. ; Gabrielli , A. ; Rinaldi , L. ; Semprini Cesari , N. ; Sioli , M. ; Villa , M. ; Zoccoli , A. ; Bellagamba , L. ; Boscherini , D. ; Bruni , A.. ; Bruni , G. ; Giacobbe , B. ; Polini , A. ; Sbarra , C. ; Sidoti , A. ; Franchini , M. ; Romano , M. ; Valentinetti , S. ; Alberghi , G. L. ; Lasagni Manghi , F; Massa , L. ; Vittori , C. ; Alfonsi , F: ; Cabras , G. ; Cervelli , A. ; Negrini , M. ; Todome , K. ; Carratta , G. ; Cavalli , N. ; Clissa , L. ; ATLAS collaborationDe Castro , S. ; Fabbri , L. ; Gabrielli , A. ; Rinaldi , L. ; Semprini Cesari , N. ; Sioli , M. ; Villa , M. ; Zoccoli , A. ; Bellagamba , L. ; Boscherini , D. ; Bruni , A. ; Bruni , G. ; Giacobbe , B. ; Polini , A. ; Sbarra , C. ; Sidoti , A. ; Franchini , M. ; Romano , M. ; Valentinetti , S. ; Alberghi , G. L. ; Lasagni Manghi , F; Massa , L. ; Vittori , C. ; Alfonsi , F: ; Cabras , G. ; Cervelli , A. ; Negrini , M. ; Todome , K. ; Carratta , G. ; Cavalli , N. ; Clissa , L. ; ATLAS collaboratio