48 research outputs found
Prospects on SM and Higgs Physics at the HL-LHC
No full textAfter a very concise summary of the Run1 results on the Higgs sector, the most important milestones in the physics programme of LHC and its luminosity upgrade HL-LHC are briefly discussed. A summary of the main Higgs boson production modes and decay final states at the HL-LHC is reported, with emphasis on the measurement of couplings to elementary bosons and fermions, and on the search for rare decay modes. Examples of interpretation of the Higgs couplings in the context of the 2HDM model, and of direct BSM Higgs bosons are briefly illustrated. Finally, the VBS process is also discussed
Standard Model Higgs searches with the ATLAS detector at the Large Hadron Collider
No full textThe investigation of the mechanism responsible for electroweak symmetry breaking is one of the most important tasks of the scientific program of the Large Hadron Collider. The experimental results on the search of the Standard Model Higgs boson with 1 to 2 fb^-1 of proton proton collision data at sqrt s=7 TeV recorded by the ATLAS detector are presented and discussed. No significant excess of events is found with respect to the expectations from Standard Model processes, and the production of a Higgs boson is excluded at 95% Confidence Level for the mass regions 144-232, 256-282 and 296-466 GeV.The investigation of the mechanism responsible for electroweak symmetry breaking is one of the most important tasks of the scientific program of the Large Hadron Collider. The experimental results on the search of the Standard Model Higgs boson with 1 to 2 fb^-1 of proton proton collision data at sqrt s=7 TeV recorded by the ATLAS detector are presented and discussed. No significant excess of events is found with respect to the expectations from Standard Model processes, and the production of a Higgs boson is excluded at 95% Confidence Level for the mass regions 144-232, 256-282 and 296-466 GeV
Prospects On Standard Model And Higgs Physics At The HL-LHC
No full textThe luminosity upgrade of LHC, HL-LHC, will provide a large statistics data set that allows precision measurements of the 125 GeV Higgs boson properties. In particular, couplings to elementary fermions and bosons will be measured at the level of a few \% accuracy. Searches for Higgs boson pair production and BSM effects in the vector boson scattering, of primary importance in the investigations of the electroweak symmetry breaking mechanism, also represent crucial point in the HL-LHC physics programme
Experimental Summary of the Second Annual Conference on Large Hadron Collider Physics
No full textHigh-quality results have been produced with the first Large Hadron Collider run on high-pT, heavy flavour and heavy ion physics. These results, as well as the most recent data analyses from Tevatron, have been presented and discussed at the LHCP2014 conference. A selection of some of them is summarised in this paper, with care to those that stimulated interesting discussions during this event
Higgs boson observation and measurements of its properties in the H→ZZ→4ℓ decay mode
No full textIn their searches for the Standard Model (SM) Higgs boson in the mass range 115-1000 GeV, both ATLAS and CMS Collaborations observed a narrow four-lepton resonance with a mass near 125 GeV with local significances in excess of 5?. In the combination of the ATLAS and CMS H→ZZ→4ℓ measurements, the mass of the observed boson was found to be 125.15 ± 0.37 (stat) ± 0.15 (syst) GeV. The event rates attributed to the signal and the studied differential cross sections were compatible with the SM Higgs boson hypothesis. Kinematic properties of leptons in signal candidate events agreed with those expected for a state with spinparity quantum numbers of the SM Higgs boson (JP = 0+) and strongly disfavoured states with alternative quantum numbers or 0+ states with non-SM-like tensor structures of their couplings to Z bosons. The yield and kinematic properties of events in the high four-lepton mass region allowed one to probe off-shell production of the discovered boson and set model-dependent upper limits on its natural width
Overview of the Large Hadron Collider and of the ATLAS and CMS experiments
No full textThe Large Hadron Collider is the most powerful particle accelerator ever built. It has allowed the discovery of a Higgs boson with mass near 125 GeV in 2012 by the ATLAS and CMS experiments. This chapter provides first an overview of the main characteristics of this collider, as well as a short description of the two general purpose experiments, ATLAS and CMS, which discovered in 2012 a Higgs boson with mass close to 125 GeV. This is followed by a summary of the main aspects of particle identification and reconstruction by these two detectors, together with a short presentation of the main analysis tools used to extract the LHC results of the Higgs boson(s) searches and measurements
LOOKING FOR THE HIGGS BOSON AND NEW PARTICLES: THE NECESSITY OF NEW DETECTOR TECHNOLOGIES
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Discovery of the Higgs boson
No full textThe recent observation of the Higgs boson has been hailed as the scientific discovery of the century and led to the 2013 Nobel Prize in physics. This book describes the detailed science behind the decades-long search for this elusive particle at the Large Electron Positron Collider at CERN and at the Tevatron at Fermilab and its subsequent discovery and characterization at the Large Hadron Collider at CERN. Written by physicists who played leading roles in this epic search and discovery, this book is an authoritative and pedagogical exposition of the portrait of the Higgs boson that has emerged from a large number of experimental measurements. As the first of its kind, this book should be of interest to graduate students and researchers in particle physics
