3,215 research outputs found

    Development of a new generation of 3D pixel sensors for HL-LHC

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    This paper covers the main technological and design aspects relevant to the development of a new generation of thin 3D pixel sensors with small pixel size aimed at the High-Luminosity LHC upgrades. (C) 2015 Elsevier B.V. All rights reserved

    The INFN-FBK "Phase-2" R&D program

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    We report on the 3-year INFN ATLAS-CMS joint research activity in collaboration with FBK, started in 2014, and aimed at the development of new thin pixel detectors for the High Luminosity LHC Phase-2 upgrades. The program is concerned with both 3D and planar active-edge pixel sensors to be made on 6" p-type wafers. The technology and the design will be optimized and qualified for extreme radiation hardness (2×1016 neq cm-2). Pixel layouts compatible with present (for testing) and future (RD53 65nm) front-end chips of ATLAS and CMS are considered. The paper covers the main aspects of the research program, from the sensor design and fabrication technology, to the results of initial tests performed on the first prototypes. © 2015 Elsevier B.V

    Measurement of the kinematic variables of beauty particles produced in 350 GeV/c ŌÄ‚ąí\pi^--Cu interactions

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    Using a sample of 2626 b\=b events, produced in 350‚ÄČGeV/c350\,\hbox{GeV}/c ŌÄ‚ąí\pi^- interactions in a copper target, which includes 1313 events where the decays of both BB and B‚Äĺ\overline{B} are well reconstructed, we measure the differential distributions with respect to xFx_F and pT2p_T^2 as well as some two-particle kinematic variables. We also compare our results with a previous experiment and with predictions based on perturbative QCD

    Azimuthal correlation between beauty particles produced in 350 GeV/c ŌÄ‚ąí\pi^{-}-Cu interactions

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    Using a sample of 10810^8 triggered events, produced in 350‚ÄČGeV/c350\, \hbox{GeV}/c ŌÄ‚ąí\pi^- interactions in a copper target, we have identified 2626 b\=b events. These include 1313 events where the decays of both BB and B‚Äĺ\overline{B} are well reconstructed. We measure the azimuthal \hbox{correlation} between beauty particles, and compare our result with predictions based on perturbative QCD

    Prototype ATLAS IBL Modules using the FE-I4A Front-End Readout Chip

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    The ATLAS Collaboration will upgrade its semiconductor pixel tracking detector with a new Insertable B-layer (IBL) between the existing pixel detector and the vacuum pipe of the Large Hadron Collider. The extreme operating conditions at this location have necessitated the development of new radiation hard pixel sensor technologies and a new front-end readout chip, called the FE-I4. Planar pixel sensors and 3D pixel sensors have been investigated to equip this new pixel layer, and prototype modules using the FE-I4A have been fabricated and characterized using 120 GeV pions at the CERN SPS and 4 GeV positrons at DESY, before and after module irradiation. Beam test results are presented, including charge collection efficiency, tracking efficiency and charge sharing.Comment: 45 pages, 30 figures, submitted to JINS

    Standalone vertex Ô¨Ānding in the ATLAS muon spectrometer

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    A dedicated reconstruction algorithm to find decay vertices in the ATLAS muon spectrometer is presented. The algorithm searches the region just upstream of or inside the muon spectrometer volume for multi-particle vertices that originate from the decay of particles with long decay paths. The performance of the algorithm is evaluated using both a sample of simulated Higgs boson events, in which the Higgs boson decays to long-lived neutral particles that in turn decay to bbar b final states, and pp collision data at ‚ąös = 7 TeV collected with the ATLAS detector at the LHC during 2011

    Measurements of Higgs boson production and couplings in diboson final states with the ATLAS detector at the LHC