416 research outputs found
Measurement of Higgs boson properties in the diphoton decay channel and a search for di-Higgs production in the gamma gamma b anti-b final state with the ATLAS detector
No full textCalibration and Performance of the ATLAS Tile Calorimeter During the LHC Run 2
No full textThe Tile Calorimeter (TileCal) is the hadronic sampling calorimeter of ATLAS experiment at the Large Hadron Collider (LHC). TileCal uses iron absorbers and scintillators as active material and it covers the central region |η| < 1.7. Jointly with the other calorimeters it is designed for measurements of hadrons, jets, tau-particles and missing transverse energy. It also assists in muon identification. TileCal is regularly monitored and calibrated by several different calibration systems: a Cs radioactive source that illuminates the scintillating tiles directly, a laser light system to directly test the PMT response, and a charge injection system (CIS) for the front-end electronics. These calibrations systems, in conjunction with data collected during proton-proton collisions, provide extensive monitoring of the instrument and a means for equalizing the calorimeter response at each stage of the signal propagation. The performance of the calorimeter has been established with cosmic ray muons and the large sample of the proton-proton collisions and compared to MC simulations. The response of high momentum isolated muons is used to study the energy response at the electromagnetic scale, isolated hadrons are used as a probe of the hadronic response. The calorimeter time resolution is studied with multijet events. A description of the different TileCal calibration systems and the results on the calorimeter performance during the LHC Run 2 will be presented. The results on the pile-up noise and response uniformity studies with MC will also be discussed
Position of the AI for Health Imaging (AI4HI) network on metadata models for imaging biobanks
No full textA huge amount of imaging data is becoming available worldwide and an incredible range of possible improvements can be provided by artificial intelligence algorithms in clinical care for diagnosis and decision support. In this context, it has become essential to properly manage and handle these medical images and to define which metadata have to be considered, in order for the images to provide their full potential. Metadata are additional data associated with the images, which provide a complete description of the image acquisition, curation, analysis, and of the relevant clinical variables associated with the images. Currently, several data models are available to describe one or more subcategories of metadata, but a unique, common, and standard data model capable of fully representing the heterogeneity of medical metadata has not been yet developed. This paper reports the state of the art on metadata models for medical imaging, the current limitations and further developments, and describes the strategy adopted by the Horizon 2020 “AI for Health Imaging” projects, which are all dedicated to the creation of imaging biobanks
Search 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
No full textÁlvarez Piqueras, D.; Aikot, Arya; Amos, K.R. ; Aparisi, Pozo, J.A.; Bailey, A.J.; Barranco, Laura; Bouchhar, Naseem; Cabrera, Susana; Cantero, Josu; Cardillo, Fabio Castillo, F.L.; Castillo Mª Victoria; Chitishvili, Mariam Cerda Alberich, L.; Costa, María José; Didenko, Mariia , Escobar, Carlos; Estrada, Oscar; Ferrer, Antonio; Fiorini, L.; Fullana, Esteban; Fuster, Juan; García García, Carmen; García Navarro, José Enrique; Gomez Delegido, A.J.; González de la Hoz, Santiago; Gonzalvo Rodríguez, Galo Rafael; Guerrero Rojas, J.G.R.; Higón, Emilio; Jimenez Pena, Javier; Lacasta Llácer, Carlos; Lozano Bahilo, José J.; Madaffari, Daniele; Mamuzic, Judita; Martí García, Salvador; Martinez Agullo, Pablo;; Melini, Davide; Miñano Moya, M.; Mitsou, Vasiliki A.; Miralles López, Marcos; Monsonis Romero, Luis; Moreno Llácer, María; Muñoz Perez, David; Navarro Gonzalez, Josep; Poveda, Joaquín; Prades Ibañez, Alberto; Rodriguez Bosca, S.; Rodriguez Rodriguez, D.; Rubio Jiménez, Adrián ; Ruiz Martínez, Arantxa; Sabatini, Paolo , Salt, José; Sanchez Sebastian, Victoria Santra, A.; Sánchez Martínez, Javier; Sayago Galvan, Ivan; Senthilkumar, Varsha ; Soldevila, Urmila; Torró Pastor, Emma; Valero, Alberto; Valls Ferrer, Juan Antonio; Valiente Moreno, Enrique ; Villaplana Pérez, Miguel , Varriale, Lorenzo; Vos, Marcel; ATLAS CollaborationA search is performed for a heavy particle decaying into different-flavour, dilepton final states, using 139 fb of proton-proton collision data at s = 13 TeV collected in 2015–2018 by the ATLAS detector at the Large Hadron Collider. Final states with electrons, muons and hadronically decaying tau leptons are considered (eμ, eτ or μτ). No significant excess over the Standard Model predictions is observed. Upper limits on the production cross-section are set as a function of the mass of a Z′ boson, a supersymmetric τ-sneutrino, and a quantum black-hole. The observed 95% CL lower mass limits obtained on a typical benchmark model Z′ boson are 5.0 TeV (eμ), 4.0 TeV (eτ), and 3.9 TeV (μτ), respectively. [Figure not available: see fulltext.].U.; Sanchez, J.; Torro Pastor, E.; Valero, A.; Valiente Moreno, E.; Valls Ferrer, J.A.; Varriale, L.; Villaplana Perez, M.; Vos, M.Peer reviewe
A 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
No full textÁlvarez Piqueras, D.; Aikot, Arya; Amos, K.R. ; Aparisi, Pozo, J.A.; Bailey, A.J.; Barranco, Laura; Bouchhar, Naseem; Cabrera, Susana; Cantero, Josu; Cardillo, Fabio Castillo, F.L.; Castillo Mª Victoria; Chitishvili, Mariam Cerda Alberich, L.; Costa, María José; Didenko, Mariia , Escobar, Carlos; Estrada, Oscar; Ferrer, Antonio; Fiorini, L.; Fullana, Esteban; Fuster, Juan; García García, Carmen; García Navarro, José Enrique; Gomez Delegido, A.J.; González de la Hoz, Santiago; Gonzalvo Rodríguez, Galo Rafael; Guerrero Rojas, J.G.R.; Higón, Emilio; Jimenez Pena, Javier; Lacasta Llácer, Carlos; Lozano Bahilo, José J.; Madaffari, Daniele; Mamuzic, Judita; Martí García, Salvador; Martinez Agullo, Pablo;; Melini, Davide; Miñano Moya, M.; Mitsou, Vasiliki A.; Miralles López, Marcos; Monsonis Romero, Luis; Moreno Llácer, María; Muñoz Perez, David; Navarro Gonzalez, Josep; Poveda, Joaquín; Prades Ibañez, Alberto; Rodriguez Bosca, S.; Rodriguez Rodriguez, D.; Rubio Jiménez, Adrián ; Ruiz Martínez, Arantxa; Sabatini, Paolo , Salt, José; Sanchez Sebastian, Victoria Santra, A.; Sánchez Martínez, Javier; Sayago Galvan, Ivan; Senthilkumar, Varsha ; Soldevila, Urmila; Torró Pastor, Emma; Valero, Alberto; Valls Ferrer, Juan Antonio; Valiente Moreno, Enrique ; Villaplana Pérez, Miguel , Varriale, Lorenzo; Vos, Marcel; ATLAS CollaborationA generic search for resonances is performed with events containing a Z boson with transverse momentum greater than 100 GeV, decaying into e e or μ μ . The analysed data collected with the ATLAS detector in proton-proton collisions at a centre-of-mass energy of 13 TeV at the Large Hadron Collider correspond to an integrated luminosity of 139 fb. Two invariant mass distributions are examined for a localised excess relative to the expected Standard Model background in six independent event categories (and their inclusive sum) to increase the sensitivity. No significant excess is observed. Exclusion limits at 95% confidence level are derived for two cases: a model-independent interpretation of Gaussian-shaped resonances with the mass width between 3% and 10% of the resonance mass, and a specific heavy vector triplet model with the decay mode W′ → ZW → ℓℓqq. [Figure not available: see fulltext.]; Senthilkumar, V.; Soldevila, U.; Sanchez, J.; Torro Pastor, E.; Valero, A.; Valls Ferrer, J.A.; Varriale, L.; Villaplana Perez, M.; Vos, M.Peer reviewe
PRIMAGE project : predictive in silico multiscale analytics to support childhood cancer personalised evaluation empowered by imaging biomarkers
No full textPRIMAGE is one of the largest and more ambitious research projects dealing with medical imaging, artificial intelligence and cancer treatment in children. It is a 4-year European Commission-financed project that has 16 European partners in the consortium, including the European Society for Paediatric Oncology, two imaging biobanks, and three prominent European paediatric oncology units. The project is constructed as an observational in silico study involving high-quality anonymised datasets (imaging, clinical, molecular, and genetics) for the training and validation of machine learning and multiscale algorithms. The open cloud-based platform will offer precise clinical assistance for phenotyping (diagnosis), treatment allocation (prediction), and patient endpoints (prognosis), based on the use of imaging biomarkers, tumour growth simulation, advanced visualisation of confidence scores, and machine-learning approaches. The decision support prototype will be constructed and validated on two paediatric cancers: neuroblastoma and diffuse intrinsic pontine glioma. External validation will be performed on data recruited from independent collaborative centres. Final results will be available for the scientific community at the end of the project, and ready for translation to other malignant solid tumours.publishe
A search for heavy Higgs bosons decaying into vector bosons in same-sign two-lepton final states in pp collisions at √s = 13 TeV with the ATLAS detector
No full textÁlvarez Piqueras, D.; Aikot, Arya; Amos, K.R. ; Aparisi, Pozo, J.A.; Bailey, A.J.; Barranco, Laura; Bouchhar, Naseem; Cabrera, Susana; Cantero, Josu; Cardillo, Fabio Castillo, F.L.; Castillo Mª Victoria; Chitishvili, Mariam Cerda Alberich, L.; Costa, María José; Didenko, Mariia , Escobar, Carlos; Estrada, Oscar; Ferrer, Antonio; Fiorini, L.; Fullana, Esteban; Fuster, Juan; García García, Carmen; García Navarro, José Enrique; Gomez Delegido, A.J.; González de la Hoz, Santiago; Gonzalvo Rodríguez, Galo Rafael; Guerrero Rojas, J.G.R.; Higón, Emilio; Jimenez Pena, Javier; Lacasta Llácer, Carlos; Lozano Bahilo, José J.; Madaffari, Daniele; Mamuzic, Judita; Martí García, Salvador; Martinez Agullo, Pablo;; Melini, Davide; Miñano Moya, M.; Mitsou, Vasiliki A.; Miralles López, Marcos; Monsonis Romero, Luis; Moreno Llácer, María; Muñoz Perez, David; Navarro Gonzalez, Josep; Poveda, Joaquín; Prades Ibañez, Alberto; Rodriguez Bosca, S.; Rodriguez Rodriguez, D.; Rubio Jiménez, Adrián ; Ruiz Martínez, Arantxa; Sabatini, Paolo , Salt, José; Sanchez Sebastian, Victoria Santra, A.; Sánchez Martínez, Javier; Sayago Galvan, Ivan; Senthilkumar, Varsha ; Soldevila, Urmila; Torró Pastor, Emma; Valero, Alberto; Valls Ferrer, Juan Antonio; Valiente Moreno, Enrique ; Villaplana Pérez, Miguel , Varriale, Lorenzo; Vos, Marcel; ATLAS CollaborationA search for heavy Higgs bosons produced in association with a vector boson and decaying into a pair of vector bosons is performed in final states with two leptons (electrons or muons) of the same electric charge, missing transverse momentum and jets. A data sample of proton–proton collisions at a centre-of-mass energy of 13 TeV recorded with the ATLAS detector at the Large Hadron Collider between 2015 and 2018 is used. The data correspond to a total integrated luminosity of 139 fb. The observed data are in agreement with Standard Model background expectations. The results are interpreted using higher-dimensional operators in an effective field theory. Upper limits on the production cross-section are calculated at 95% confidence level as a function of the heavy Higgs boson’s mass and coupling strengths to vector bosons. Limits are set in the Higgs boson mass range from 300 to 1500 GeV, and depend on the assumed couplings. The highest excluded mass for a heavy Higgs boson with the coupling combinations explored is 900 GeV. Limits on coupling strengths are also provided. [Figure not available: see fulltext.]Article funded by SCOAP3.Peer reviewe
Modelling and computational improvements to the simulation of single vector-boson plus jet processes for the ATLAS experiment
No full textÁlvarez Piqueras, D.; Aikot, Arya; Amos, K.R. ; Aparisi, Pozo, J.A.; Bailey, A.J.; Barranco, Laura; Bouchhar, Naseem; Cabrera, Susana; Cantero, Josu; Cardillo, Fabio Castillo, F.L.; Castillo Mª Victoria; Chitishvili, Mariam Cerda Alberich, L.; Costa, María José; Didenko, Mariia , Escobar, Carlos; Estrada, Oscar; Ferrer, Antonio; Fiorini, L.; Fullana, Esteban; Fuster, Juan; García García, Carmen; García Navarro, José Enrique; Gomez Delegido, A.J.; González de la Hoz, Santiago; Gonzalvo Rodríguez, Galo Rafael; Guerrero Rojas, J.G.R.; Higón, Emilio; Jimenez Pena, Javier; Lacasta Llácer, Carlos; Lozano Bahilo, José J.; Madaffari, Daniele; Mamuzic, Judita; Martí García, Salvador; Martinez Agullo, Pablo;; Melini, Davide; Miñano Moya, M.; Mitsou, Vasiliki A.; Miralles López, Marcos; Monsonis Romero, Luis; Moreno Llácer, María; Muñoz Perez, David; Navarro Gonzalez, Josep; Poveda, Joaquín; Prades Ibañez, Alberto; Rodriguez Bosca, S.; Rodriguez Rodriguez, D.; Rubio Jiménez, Adrián ; Ruiz Martínez, Arantxa; Sabatini, Paolo , Salt, José; Sanchez Sebastian, Victoria Santra, A.; Sánchez Martínez, Javier; Sayago Galvan, Ivan; Senthilkumar, Varsha ; Soldevila, Urmila; Torró Pastor, Emma; Valero, Alberto; Valls Ferrer, Juan Antonio; Valiente Moreno, Enrique ; Villaplana Pérez, Miguel , Varriale, Lorenzo; Vos, Marcel; ATLAS CollaborationThis paper presents updated Monte Carlo configurations used to model the production of single electroweak vector bosons (W, Z/γ) in association with jets in proton-proton collisions for the ATLAS experiment at the Large Hadron Collider. Improvements pertaining to the electroweak input scheme, parton-shower splitting kernels and scale-setting scheme are shown for multi-jet merged configurations accurate to next-to-leading order in the strong and electroweak couplings. The computational resources required for these set-ups are assessed, and approximations are introduced resulting in a factor three reduction of the per-event CPU time without affecting the physics modelling performance. Continuous statistical enhancement techniques are introduced by ATLAS in order to populate low cross-section regions of phase space and are shown to match or exceed the generated effective luminosity. This, together with the lower per-event CPU time, results in a 50% reduction in the required computing resources compared to a legacy set-up previously used by the ATLAS collaboration. The set-ups described in this paper will be used for future ATLAS analyses and lay the foundation for the next generation of Monte Carlo predictions for single vector-boson plus jets production. [Figure not available: see fulltext.]
Measurement of the ZZ production cross section in proton-proton collisions at root s=8 TeV using the ZZ -> l(-) l(+) l '(-) l '(+) and ZZ -> l(-) l(+) nu(nu)over-bar decay channels with the ATLAS detector
No full textA measurement of the ZZ production cross section in the l(-)l(+)l'(-)l'(+) and l(-)l(+) nu(nu) over bar channels (l = e, mu) in proton-proton collisions at root s = 8TeV at the Large Hadron Collider at CERN, using data corresponding to an integrated luminosity of 20.3 fb(-1) collected by the ATLAS experiment in 2012 is presented. The fi ducial cross sections for ZZ -> l(-)l(+)l'(-)l'(+) and ZZ -> l(-)l(+) nu(nu) over bar are measured in selected phase-space regions. The total cross section for ZZ events produced with both Z bosons in the mass range 66 to 116 GeV is measured from the combination of the two channels to be 7.3 +/- 0.4 (stat) +/- 0.3 (syst) (-0.2)(-0.1) (lumi) pb, which is consistent with the Standard Model prediction of 6.6(-0.6)(+0.7) pb. The di ff erential cross sections in bins of various kinematic variables are presented. The differential event yield as a function of the transverse momentum of the leading Z boson is used to set limits on anomalous neutral triple gauge boson couplings in ZZ production
Measurement of the top-quark mass using a leptonic invariant mass in pp collisions at root s=13 TeV with the ATLAS detector
No full textA measurement of the top-quark mass (mt) in the tt ̄ → lepton + jets channel is presented, with an experimental technique which exploits semileptonic decays of b-hadrons produced in the top-quark decay chain. The distribution of the invariant mass mlμ of the lepton, l (with l = e, μ), from the W-boson decay and the muon, μ, originating from the b-hadron decay is reconstructed, and a binned-template profile likelihood fit is performed to extract mt. The measurement is based on data corresponding to an integrated luminosity of 36.1 fb−1 of s = 13 TeV pp collisions provided by the Large Hadron Collider and recorded by the ATLAS detector. The measured value of the top-quark mass is mt = 174.41 ± 0.39 (stat.) ± 0.66 (syst.) ± 0.25 (recoil) GeV, where the third uncertainty arises from changing the Pythia8 parton shower gluon-recoil scheme, used in top-quark decays, to a recently developed setup. [Figure not available: see fulltext.]
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