The luminosity calibration for the ATLAS detector at the LHC during pp collisions at [equation]in 2010 and 2011 is presented. Evaluation of the luminosity scale is performed using several...

A measurement of the production processes of the recently discovered Higgs boson is performed in the two-photon final state using $4.5{\mathrm{fb}}^{-1}$ of proton-proton collisions data at $\sqrt{s}=7\mathrm{TeV}$ and $20.3{\mathrm{fb}}^{-1}$ at $\sqrt{s}=8\mathrm{TeV}$ collected by the ATLAS detector at the Large Hadron Collider. The number of observed Higgs boson decays to diphotons divided by the corresponding Standard Model prediction, called the signal strength, is found to be $\mu =1.17\pm 0.27$ at the value of the Higgs boson mass measured by ATLAS, $m_H=125.4\mathrm{GeV}$. The analysis is optimized to measure the signal strengths for individual Higgs boson production processes at this value of $m_H$. They are found to be ${\mu }_{\mathrm{ggF}}=1.32\pm 0.38$, ${\mu }_{\mathrm{VBF}}=0.8\pm 0.7$, ${\mu }_{WH}=1.0\pm 1.6$, ${\mu }_{ZH}={0.1}_{-0.1}^{+3.7}$, and ${\mu }_{t\overline{t}H}={1.6}_{-1.8}^{+2.7}$, for Higgs boson production through gluon fusion, vector-boson fusion, and in association with a $W$ or $Z$ boson or a top-quark pair, respectively. Compared with the previously published ATLAS analysis, the results reported here also benefit from a new energy calibration procedure for photons and the subsequent reduction of the systematic uncertainty on the diphoton mass resolution. No significant deviations from the predictions of the Standard Model are found.

The Advanced GAmma Tracking Array (AGATA) is a European project to develop and operate the next generation gamma-ray spectrometer. AGATA is based on the technique of gamma-ray energy tracking in electrically segmented high-purity germanium crystals. This technique requires the accurate determination of the energy, time and position of every interaction as a gamma ray deposits its energy within the detector volume. Reconstruction of the full interaction path results in a detector with very high efficiency and excellent spectral response. The realisation of gamma-ray tracking and AGATA is a result of many technical advances. These include the development of encapsulated highly segmented germanium detectors assembled in a triple cluster detector cryostat, an electronics system with fast digital sampling and a data acquisition system to process the data at a high rate. The full characterisation of the crystals was measured and compared with detector-response simulations. This enabled pulse-shape analysis algorithms, to extract energy, time and position, to be employed. In addition, tracking algorithms for event reconstruction were developed. The first phase of AGATA is now complete and operational in its first physics campaign. In the future AGATA will be moved between laboratories in Europe and operated in a series of campaigns to take advantage of the different beams and facilities available to maximise its science output. The paper reviews all the achievements made in the AGATA project including all the necessary infrastructure to operate and support the spectrometer. (C) 2011 Elsevier B.V. All rights reserved.AGATA and this work is supported by the European funding bodies and the EU Contract RII3-CT-2004-506065, the German BMBF under Grants 06K-167 and 06KY205I, the Swedish Research Council and the Knut and Alice Wallenberg Foundation, UK EPSRC Engineering and Physical Sciences Research Council, UK STFC Science and Technology Facilities Council, AWE plc, Scientific and Technological Research Council of Turkey (Proj. nr. 106T055) and Ankara University (BAP Proj. nr. 05B4240002), the Polish Ministry of Science and Higher Education under Grant DPN/N190/AGATA/2009, the Spanish MICINN under grants FPA2008-06419 and FPA2009-13377-C02-02, the Spanish Consolider-Ingenio 2010 Programme CPAN (contract number CSD2007-00042) the Generalitat Valenciana under Grant PROMETEO/2010/101, and research performed in the frame of the GSI-IN2P3 collaboration agreement number 02-42. MICINN, Spain, and INFN, Italy, through the AIC10-D-000568 bilateral action.Peer Reviewe

This paper presents the performance of the ATLAS muon reconstruction during the LHC run with [equation] collisions at [equation]–8 TeV in 2011–2012, focusing mainly on data collected in 2012....

This paper presents the electron and photon energy calibration achieved with the ATLAS detector using about 25 fb[equation] of LHC proton–proton collision data taken at centre-of-mass energies of [equation]...

Many of the interesting physics processes to be measured at the LHC have a signature involving one or more isolated electrons. The electron reconstruction and identification efficiencies of the ATLAS detector at the LHC have been evaluated using proton–proton collision data collected in 2011 at \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\sqrt{s}= 7$$\end{document}s=7 TeV and corresponding to an integrated luminosity of 4.7 fb\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$^{-1}$$\end{document}-1. Tag-and-probe methods using events with leptonic decays of \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$W$$\end{document}W and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$Z$$\end{document}Z bosons and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$J/\psi $$\end{document}J/ψ mesons are employed to benchmark these performance parameters. The combination of all measurements results in identification efficiencies determined with an accuracy at the few per mil level for electron transverse energy greater than 30 GeV.