10 research outputs found

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

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    Searches 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

    Search for single vector-like B quark production and decay via B → bH(b¯b) in pp collisions at √s = 13 TeV with the ATLAS detector

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    A search is presented for single production of a vector-like B quark decaying into a Standard Model b-quark and a Standard Model Higgs boson, which decays into a b¯b pair. The search is carried out in 139 fb−1 of √s = 13 TeV proton-proton collision data collected by the ATLAS detector at the LHC between 2015 and 2018. No significant deviation from the Standard Model background prediction is observed, and mass-dependent exclusion limits at the 95% confidence level are set on the resonance production cross-section in several theoretical scenarios determined by the couplings cW, cZ and cH between the B quark and the Standard Model W, Z and Higgs bosons, respectively. For a vector-like B occurring as an isospin singlet, the search excludes values of cW greater than 0.45 for a B resonance mass (mB) between 1.0 and 1.2 TeV. For 1.2 TeV < mB < 2.0 TeV, cW values larger than 0.50–0.65 are excluded. If the B occurs as part of a (B, Y) doublet, the smallest excluded cZ coupling values range between 0.3 and 0.5 across the investigated resonance mass range 1.0 TeV < mB < 2.0 TeV

    Concept Shifting and the Radical Product Development Process

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    Radical product development projects, which are undertaken to create new categories of products, present significant challenges to development teams. In such settings existing formal processes may be limited or inappropriate, and objectives may be ambiguous and changing. The generation of a novel product concept early in the process can play an important role in guiding development teams, but the process by which teams later change concepts, as may be required within radical contexts, has merited further research. This study investigated how teams change novel product concepts after initial generation, employing an inductive case-study method drawing from 51 interviews with members of six radical development projects. The empirical results found that concepts were described in terms of concept components—elemental descriptive forms that included verbal stories, verbal metaphors, and physical prototypes. When changes were required to concepts due to new technical or market information, rather than reconsider the overall concept through iteration to earlier product definition stages, teams shifted individual concept components, with a new component replacing a component of similar descriptive form. Over half of concept components observed across cases came after the initial generation of concepts in later elaboration and shifting. Contrary to expectations, development teams maintained reference not only to the revised concept but also to the deferred original concept. The case of a novel electronic book development project is used to illustrate the process, along with evidence of concept shifting across cases. The detailed findings expand our understanding of how formal processes may be augmented in radical innovation settings and how concepts are actually used by development teams in changing circumstances

    Conceptualizing business process re-engineering

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    The ATLAS Fast TracKer system

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    Abstract: The ATLAS Fast TracKer (FTK) was designed to provide full tracking for the ATLAS high-level trigger by using pattern recognition based on Associative Memory (AM) chips and fitting in high-speed field programmable gate arrays. The tracks found by the FTK are based on inputs from all modules of the pixel and silicon microstrip trackers. The as-built FTK system and components are described, as is the online software used to control them while running in the ATLAS data acquisition system. Also described is the simulation of the FTK hardware and the optimization of the AM pattern banks. An optimization for long-lived particles with large impact parameter values is included. A test of the FTK system with the data playback facility that allowed the FTK to be commissioned during the shutdown between Run 2 and Run 3 of the LHC is reported. The resulting tracks from part of the FTK system covering a limited η–ϕ region of the detector are compared with the output from the FTK simulation. It is shown that FTK performance is in good agreement with the simulation

    Search for new phenomena in three- or four-lepton events in pp collisions at root s=13 TeV with the ATLAS detector

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    We thank CERN for the very successful operation of the LHC, as well as the support staff from our institutions without whom ATLAS could not be operated efficiently. We acknowledge the support of ANPCyT, Argentina; YerPhI, Ar-menia; ARC, Australia; BMWFW and FWF, Austria; ANAS, Azerbai-jan; SSTC, Belarus; CNPq and FAPESP, Brazil; NSERC, NRC and CFI, Canada; CERN; ANID, Chile; CAS, MOST and NSFC, China; Min-ciencias, Colombia; MSMT CR, MPO CR and VSC CR, Czech Repub-lic; DNRF and DNSRC, Denmark; IN2P3-CNRS and CEA-DRF/IRFU, France; SRNSFG, Georgia; BMBF, HGF and MPG, Germany; GSRI, Greece; RGC and Hong Kong SAR, China; ISF and Benoziyo Cen-ter, Israel; INFN, Italy; MEXT and JSPS, Japan; CNRST, Morocco; NWO, Netherlands; RCN, Norway; MEiN, Poland; FCT, Portugal; MNE/IFA, Romania; JINR; MES of Russia and NRC KI, Russian Fed-eration; MESTD, Serbia; MSSR, Slovakia; ARRS and MIZŠ, Slovenia; DSI/NRF, South Africa; MICINN, Spain; SRC and Wallenberg Founda-tion, Sweden; SERI, SNSF and Cantons of Bern and Geneva, Switzer-land; MOST, Taiwan; TAEK, Turkey; STFC, United Kingdom; DOE and NSF, United States of America. In addition, individual groups and members have received support from BCKDF, CANARIE, Com-pute Canada and CRC, Canada; COST, ERC, ERDF, Horizon 2020 and Marie Skłodowska-Curie Actions, European Union; Investisse-ments d’Avenir Labex, Investissements d’Avenir Idex and ANR, France; DFG and AvH Foundation, Germany; Herakleitos, Thales and Aristeia programmes co-financed by EU-ESF and the Greek NSRF, Greece; BSF-NSF and GIF, Israel; Norwegian Financial Mecha-nism 2014-2021, Norway; NCN and NAWA, Poland; La Caixa Bank-ing Foundation, CERCA Programme Generalitat de Catalunya and PROMETEO and GenT Programmes Generalitat Valenciana, Spain; Göran Gustafssons Stiftelse, Sweden; The Royal Society and Lever-hulme Trust, United Kingdom. The crucial computing support from all WLCG partners is ac-knowledged gratefully, in particular from CERN, the ATLAS Tier-1 facilities at TRIUMF (Canada), NDGF (Denmark, Norway, Sweden), CC-IN2P3 (France), KIT/GridKA (Germany), INFN-CNAF (Italy), NL-T1 (Netherlands), PIC (Spain), ASGC (Taiwan), RAL (UK) and BNL (USA), the Tier-2 facilities worldwide and large non-WLCG resource providers. Major contributors of computing resources are listed in Ref.[91].A search with minimal model dependence for physics beyond the Standard Model in events featuring three or four charged leptons (3l and 4l, l = e, mu) is presented. The analysis aims to be sensitive to a wide range of potential new-physics theories simultaneously. This analysis uses data from pp collisions delivered by the Large Hadron Collider at a centre-of-mass energy of root s = 13 TeV and recorded with the ATLAS detector, corresponding to the full Run 2 dataset of 139 fb(-1). The 3l and 4l phase space is divided into 22 event categories according to the number of leptons in the event, the missing transverse momentum, the invariant mass of the leptons, and the presence of leptons originating from a Z-boson candidate. These event categories are analysed independently for the presence of deviations from the Standard Model. No statistically significant deviations from the Standard Model predictions are observed. Upper limits for all signal regions are reported in terms of the visible cross-section.ANPCyT, ArgentinaYerPhI, ArmeniaARC, AustraliaBMWFW and FWF, AustriaANAS, AzerbaijanSSTC, BelarusCNPq and FAPESP, BrazilNSERC, NRC and CFI, CanadaCERNANID, ChileCAS, MOST and NSFC, ChinaMinciencias, ColombiaMSMT CR, MPO CR and VSC CR, Czech RepublicDNRF and DNSRC, DenmarkIN2P3-CNRS and CEA-DRF/IRFU, FranceSRNSFG, GeorgiaBMBF, HGF and MPG, GermanyGSRI, GreeceRGC and Hong Kong SAR, ChinaISF and Benoziyo Center, IsraelINFN, ItalyMEXT and JSPS, JapanCNRST, MoroccoNWO, NetherlandsRCN, NorwayMEiN, PolandFCT, PortugalMNE/IFA, RomaniaJINRMES of Russia and NRC KI, Russian FederationMESTD, SerbiaMSSR, SlovakiaARRS and MIZŠ, SloveniaDSI/NRF, South AfricaMICINN, SpainSRC and Wallenberg Foundation, SwedenSERI, SNSF and Cantons of Bern and Geneva, SwitzerlandMOST, TaiwanTAEK, TurkeySTFC, United KingdomDOE and NSF, United States of AmericaBCKDF, CANARIE, Compute Canada and CRC, CanadaCOST, ERC, ERDF, Horizon 2020 and Marie Skłodowska-Curie Actions, European UnionInvestissements d’Avenir Labex, Investissements d’Avenir Idex and ANR, FranceDFG and AvH Foundation, GermanyHerakleitos, Thales and Aristeia programmes co-financed by EU-ESF and the Greek NSRF, GreeceBSF-NSF and GIF, IsraelNorwegian Financial Mechanism 2014-2021, NorwayNCN and NAWA, PolandLa Caixa Banking Foundation, CERCA Programme Generalitat de Catalunya and PROMETEO and GenT Programmes Generalitat Valenciana, SpainGöran Gustafssons Stiftelse, SwedenThe Royal Society and Leverhulme Trust, United Kingdo

    Evidence for Higgs boson decays to a low-mass dilepton system and a photon in pp collisions at s=13 TeV with the ATLAS detector

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    A search for the Higgs boson decaying into a photon and a pair of electrons or muons with an invariant mass mℓℓ<30 GeV is presented. The analysis is performed using 139 fb−1 of proton–proton collision data, produced by the LHC at a centre-of-mass energy of 13 TeV and collected by the ATLAS experiment. Evidence for the H→ℓℓγ process is found with a significance of 3.2 over the background-only hypothesis, compared to an expected significance of 2.1 for the Standard Model prediction. The best-fit value of the signal-strength parameter, defined as the ratio of the observed signal yield to the one expected in the Standard Model, is μ=1.5±0.5. The Higgs boson production cross-section times the H→ℓℓγ branching ratio for mℓℓ<30 GeV is determined to be 8.7−2.7+2.8 fb
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