3,400 research outputs found
Measurements of underlying-event properties using neutral and charged particles in pp collisions at √s=900 GeV and √s=7TeV with the ATLAS detector at the LHC
No full textWe present first measurements of charged and neutral particle-flow correlations in pp collisions using the ATLAS calorimeters. Data were collected in 2009 and 2010 at centre-of-mass energies of 900 GeV and 7 TeV. Events were selected using a minimum-bias trigger which required a charged particle in scintillation counters on either side of the interaction point. Particle flows, sensitive to the underlying event, are measured using clusters of energy in the ATLAS calorimeters, taking advantage of their fine granularity. No Monte Carlo generator used in this analysis can accurately describe the measurements. The results are independent of those based on charged particles measured by the ATLAS tracking systems and can be used to constrain the parameters of Monte Carlo generators
The ATLAS Higgs Boson Machine Learning Challenge
No full textOn behalf of the ATLAS Collaboration - Proceedings of the 37 International Conference on High Energy Physics (ICHEP 2014) will be published in Nuclear Physics B - Proceedings SupplementsHigh Energy Physics began utilising Machine Learning technique such as Multivariate Analysis, Neural Nets and Boosted Decision Trees since the 90's, but the connections between the HEP scientific community and the computer science community are poor and can be improved. In HEP there are exciting and difficult problems such as the extraction of the Higgs boson signal, while computer scientists are eager to develop advanced algorithms. The goal of the HiggsML project is to bring the two fields together by means of a "challenge", where participants from all over the world and any scientific background can compete to obtain the best signal over background ratio on a set of simulated data. The challenge was organized by the ATLAS collaboration, the LAL and INRIA-Saclay in partnership with CERN and Google. It will run between May 2014 and September 2014 to encourage participation of students and professors. The organization, the startup and prospects of the challenge, which is half way between outreach and physics analysis, will be described
Extraction of the the Susy and Higgs parameters
No full texton behalf of the SFitter collaborationInternational audienceThe extraction of the fundamental parameters of supersymmetry and the Higgs sector will be a difficult task at the LHC and ILC. In this report, we will study the use the Higgs sector measurements alone at the LHC to differentiate between the Standard Model and a supersymmetric parameter set as a pessimistic scenario. Then, in an optimistic scenario, we will study the extrapolation to the high scale using many supersymmetric measurements at the LHC and ILC
The ATLAS Higgs Boson Machine Learning Challenge
No full textOn behalf of the ATLAS Collaboration - Proceedings of the 37 International Conference on High Energy Physics (ICHEP 2014) will be published in Nuclear Physics B - Proceedings SupplementsHigh Energy Physics began utilising Machine Learning technique such as Multivariate Analysis, Neural Nets and Boosted Decision Trees since the 90's, but the connections between the HEP scientific community and the computer science community are poor and can be improved. In HEP there are exciting and difficult problems such as the extraction of the Higgs boson signal, while computer scientists are eager to develop advanced algorithms. The goal of the HiggsML project is to bring the two fields together by means of a "challenge", where participants from all over the world and any scientific background can compete to obtain the best signal over background ratio on a set of simulated data. The challenge was organized by the ATLAS collaboration, the LAL and INRIA-Saclay in partnership with CERN and Google. It will run between May 2014 and September 2014 to encourage participation of students and professors. The organization, the startup and prospects of the challenge, which is half way between outreach and physics analysis, will be described
Measurement of VH, H→bb¯ production as a function of the vector-boson transverse momentum in 13 TeV pp collisions with the ATLAS detector
No full textCross-sections of associated production of a Higgs boson decaying into bottom-quark pairs and an electroweak gauge boson, W or Z, decaying into leptons are measured as a function of the gauge boson transverse momentum. The measurements are performed in kinematic fiducial volumes defined in the `simplified template cross-section´ framework. The results are obtained using 79.8 fb−1 of proton-proton collisions recorded by the ATLAS detector at the Large Hadron Collider at a centre-of-mass energy of 13 TeV. All measurements are found to be in agreement with the Standard Model predictions, and limits are set on the parameters of an effective Lagrangian sensitive to modifications of the Higgs boson couplings to the electroweak gauge bosons.Fil: Aaboud, M.. Université Mohamed; MarruecosFil: Aad, G.. Aix-Marseille Université; Francia. Centre National de la Recherche Scientifique; FranciaFil: Abbott, B.. University of Oklahoma; Estados UnidosFil: Abbott, D. C.. University of Oklahoma; Estados UnidosFil: Abdinov, O.. Azerbaijan Academy of Sciences; AzerbaiyánFil: Abed Abud, A.. Universita degli Studi di Pavia; Italia. Istituto Nazionale di Fisica Nucleare; ItaliaFil: Abhayasinghe, D. K.. Royal Holloway University of London; Reino UnidoFil: Abidi, S. H.. University of Toronto; CanadáFil: AbouZeid, O. S.. Universidad de Copenhagen; DinamarcaFil: Abraham, N. L.. University of Sussex; Reino UnidoFil: Abramowicz, H.. Universitat Tel Aviv; IsraelFil: Abreu, H.. Technion - Israel Institute of Technology; IsraelFil: Abulaiti, Y.. Argonne National Laboratory; Estados UnidosFil: Acharya, B. S.. Istituto Nazionale di Fisica Nucleare; Italia. The Abdus Salam. International Centre for Theoretical Physics; Italia. King’s College London; Reino UnidoFil: Adachi, S.. University of Tokyo; JapónFil: Adam, L.. Universität Mainz; AlemaniaFil: Adam Bourdarios, C.. Université Paris-Sud; Francia. Universite Paris-Saclay; . Centre National de la Recherche Scientifique; FranciaFil: Adamczyk, L.. University of Science and Technology; PoloniaFil: Adamek, L.. University of Toronto; CanadáFil: Adelman, J.. Northern Illinois University; Estados UnidosFil: Adersberger, M.. Ludwig-Maximilians-Universität München; AlemaniaFil: Adiguzel, A.. Bogazici University; Turquía. Istanbul University; TurquíaFil: Adorni, S.. Université de Genève; FranciaFil: Adye, T.. Rutherford Appleton Laboratory; Reino UnidoFil: Affolder, A. A.. University of California Santa Cruz; Estados UnidosFil: Afik, Y.. Technion - Israel Institute of Technology; IsraelFil: Agapopoulou, C.. Université Paris-Sud; Francia. Centre National de la Recherche Scientifique; Francia. Universite Paris-Saclay;Fil: Agaras, M. N.. Université Clermont Auvergne; Francia. Centre National de la Recherche Scientifique; FranciaFil: Aggarwal, A.. Radboud Universiteit Nijmegen; Países BajosFil: Arduh, Francisco Anuar. Cern - European Organization for Nuclear Research; Suiza. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; Argentin
Involving other communities through challenges and cooperation
No full textInternational audienceThe ATLAS collaboration has recently setup three projects targeting citizen science or specific communities :The goal of the HiggsML project was to bring particle physicists and data scientist together by a “challenge”: compete online to obtain the best Higgs to tau tau signal significance on a set of ATLAS fully simulated signal and background. The challenge ran from May to September 2014, drawing considerable attention. 1785 teams participated, making it the most popular challenge ever on the Kaggle platform.Higgs Hunters is the first Particle Physics project hosted on a web-based citizen science platform called Zooniverse. Volunteers are asked to scan ATLAS data and Monte Carlo events, looking for secondary vertices. Results will be compared to the ATLAS secondary vertex finding algorithm in the context of the search for long lived particles in Supersymmetric models. So far more than 5,000 users have taken part, classifying more than 600,000 interesting features in ATLAS event displays.The ATLAS @ home project allows volunteers to run simulations of collisions in the ATLAS detector. During the first year the community essentially consisted of software fans, who were attracted by the technical challenge and contributed a lot to the debugging via message boards. With the start of LHC, the number of people attracted for outreach reasons is growing.In this talk, the setup, current success and future of such projects are reviewed
Involving other communities through challenges and cooperation
No full textInternational audienceThe ATLAS collaboration has recently setup three projects targeting citizen science or specific communities :The goal of the HiggsML project was to bring particle physicists and data scientist together by a “challenge”: compete online to obtain the best Higgs to tau tau signal significance on a set of ATLAS fully simulated signal and background. The challenge ran from May to September 2014, drawing considerable attention. 1785 teams participated, making it the most popular challenge ever on the Kaggle platform.Higgs Hunters is the first Particle Physics project hosted on a web-based citizen science platform called Zooniverse. Volunteers are asked to scan ATLAS data and Monte Carlo events, looking for secondary vertices. Results will be compared to the ATLAS secondary vertex finding algorithm in the context of the search for long lived particles in Supersymmetric models. So far more than 5,000 users have taken part, classifying more than 600,000 interesting features in ATLAS event displays.The ATLAS @ home project allows volunteers to run simulations of collisions in the ATLAS detector. During the first year the community essentially consisted of software fans, who were attracted by the technical challenge and contributed a lot to the debugging via message boards. With the start of LHC, the number of people attracted for outreach reasons is growing.In this talk, the setup, current success and future of such projects are reviewed
Education and outreach through building blocks
No full textInternational audienceTo support the outreach activities of Atlas institutes and to grab people's attention in science exhibitions and during public events, we have created both a very detailed model of the experiment built entirely out of Lego bricks as well as an outreach programme using Lego bricks to get people to think about particle detectors and involve them in a conversation about particle physics in general. A large Lego model, consisting of about 9500 pieces, has been 'exported' to more than 55 Atlas institutes and has been used in numerous exhibitions to explain the proportion and composition of the experiment to the public. As part of 'Build Your Own Particle Detector' programme (byopd.org) we conducted more than 15 events, either involving a competition to design and build the 'best' particle detector from a random pile of pieces or to take part in the construction of one of the large models, as part of a full day outreach event. Recently we've added miniature models of all four LHC experiments, that will be used at various outreach events in the future
- …
