15 research outputs found

    Measurement of the inclusive cross-section for the production of jets in association with a Z boson in proton-proton collisions at 8 TeV using the ATLAS detector

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    The inclusive cross-section for jet production in association with a Z boson decaying into an electron–positron pair is measured as a function of the transverse momentum and the absolute rapidity of jets using 19.9 fb −1 of s√=8 TeV proton–proton collision data collected with the ATLAS detector at the Large Hadron Collider. The measured Z + jets cross-section is unfolded to the particle level. The cross-section is compared with state-of-the-art Standard Model calculations, including the next-to-leading-order and next-to-next-to-leading-order perturbative QCD calculations, corrected for non-perturbative and QED radiation effects. The results of the measurements cover final-state jets with transverse momenta up to 1 TeV, and show good agreement with fixed-order calculations

    Radiation hard silicon detectors - developments by the RD48 (ROSE)collaboration

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    The RD48 (ROSE) collaboration has succeeded to develop radiation hard silicon detectors. capable to withstand the harsh hadron fluences in the tracking areas of LHC experiments. In order to reach this objective, a defect engineering technique was employed resulting in the development of Oxygen enriched FZ silicon (DOFZ), ensuring the necessary O-enrichment of about 2 x 10(17) O/cm(3) in the normal detector processing. Systematic investigations have been carried out on various standard and oxygenated silicon diodes with neutron, proton and pion irradiation up to a fluence of 5 x 10(14)cm(-2) (1 MeV neutron equivalent). Major focus is on the changes of the effective doping concentration (depletion voltage). Other aspects (reverse current, charge collection) are covered too and the appreciable benefits obtained with DOFZ silicon in radiation tolerance for charged hadrons are outlined. The results are reliably described by the "Hamburg model": its application to LHC experimental conditions is shown, demonstrating the superiority of the defect engineered silicon. Microscopic aspects of damage effects are also discussed. including differences due to charged and neutral hadron irradiation. (C) 2001 Elsevier Science B.V. All rights reserved

    Development of radiation tolerant semiconductor detectors for the Super-LHC.

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    The envisaged upgrade of the Large Hadron Collider (LHC) at CERN towards the Super-LHC (SLHC) with a 10 times increased luminosity of 1035 cm−2 s−1 will present severe challenges for the tracking detectors of the SLHC experiments. Unprecedented high radiation levels and track densities and a reduced bunch crossing time in the order of 10 ns as well as the need for cost effective detectors have called for an intensive R&D program. The CERN RD50 collaboration “Development of Radiation Hard Semiconductor Devices for Very High Luminosity Colliders” is working on the development of semiconductor sensors matching the requirements of the SLHC. Sensors based on defect engineered silicon like Czochralski, epitaxial and oxygen enriched silicon have been developed. With 3D, Semi-3D and thin detectors new detector concepts have been evaluated and a study on the use of standard and oxygen enriched p-type silicon detectors revealed a promising approach for radiation tolerant cost effective devices. These and other most recent advancements of the RD50 collaboration are presented

    Recent advancements in the development of radiation hard semiconductor detectors for S-LHC

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    The proposed luminosity upgrade of the Large Hadron Collider (S-LHC) at CERN will demand the innermost layers of the vertex detectors to sustain fluences of about 1016 hadrons/cm2. Due to the high multiplicity of tracks, the required spatial resolution and the extremely harsh radiation field new detector concepts and semiconductor materials have to be explored for a possible solution of this challenge. The CERN RD50 collaboration “Development of Radiation Hard Semiconductor Devices for Very High Luminosity Colliders” has started in 2002 an R&D program for the development of detector technologies that will fulfill the requirements of the S-LHC. Different strategies are followed by RD50 to improve the radiation tolerance. These include the development of defect engineered silicon like Czochralski, epitaxial and oxygen-enriched silicon and of other semiconductor materials like SiC and GaN as well as extensive studies of the microscopic defects responsible for the degradation of irradiated sensors. Further, with 3D, Semi-3D and thin devices new detector concepts have been evaluated. These and other recent advancements of the RD50 collaboration are presented and discussed

    Radiation-hard semiconductor detectors for SuperLHC.

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    An option of increasing the luminosity of the Large Hadron Collider (LHC) at CERN to 1035 cm−2 s−1 has been envisaged to extend the physics reach of the machine. An efficient tracking down to a few centimetres from the interaction point will be required to exploit the physics potential of the upgraded LHC. As a consequence, the semiconductor detectors close to the interaction region will receive severe doses of fast hadron irradiation and the inner tracker detectors will need to survive fast hadron fluences of up to above 1016 cm−2. The CERN-RD50 project “Development of Radiation Hard Semiconductor Devices for Very High Luminosity Colliders” has been established in 2002 to explore detector materials and technologies that will allow to operate devices up to, or beyond, this limit. The strategies followed by RD50 to enhance the radiation tolerance include the development of new or defect engineered detector materials (SiC, GaN, Czochralski and epitaxial silicon, oxygen enriched Float Zone silicon), the improvement of present detector designs and the understanding of the microscopic defects causing the degradation of the irradiated detectors. The latest advancements within the RD50 collaboration on radiation hard semiconductor detectors will be reviewed and discussed in this work

    Measurement of D(s)+ meson production in Z decays and of the anti-B(s)0 lifetime

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    D-s(+) mesons produced in Z(0) --> b (b) over bar events were separated from the Z(0) --> c (c) over bar component using a lifetime tag. Using a sample of 1.5 million hadronic Z decays collected with the ALEPH detector the (B) over bar(s)(0) and D-s(+) yields have been measured: [GRAPHICS] The (B) over bar(2)(0) lifetime was measured in a (B) over bar(s)(0) enriched sample reconstructing the decay length from the vertex of the D-s(+) with a hadron from the (B) over bar(0)(s) decay, The result obtained is: [GRAPHICS

    Measurements of the b baryon lifetime

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    Using about 1.5 million hadronic Z decays recorded with the aleph detector, the lifetime of the b baryons has been measured using two independent data samples. From a maximum likelihood fit to the impact parameter distribution of leptons in 519 Λℓ− combinations containing a b baryon sample of 290 decays, the measured b baryon lifetime is τb—baryon = 1.05−0.11+0.12(stat)±0.09(syst) ps. The lifetime of the Λb0 baryon from a maximum likelihood fit to the proper time distribution of 58 Λc+ℓ− candidates containing a Λb0 sample of 44 decays, is τΛb0 = 1.02−0.18+0.23(stat) ± 0.06(syst) ps

    Measurement of the D*± cross section in two photon collisions at LEP

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    complete author list: Buskulic D.; Casper D.; De Bonis I.; Decamp D.; Ghez P.; Goy C.; Lees J.; Minard M.; Odier P.; Pietrzyk B.; Ariztizabal F.; Chmeissani M.; Crespo J.; Efthymiopoulos I.; Fernandez E.; Fernandez-Bosman M.; Gaitan V.; Garrido L.; Martinez M.; Orteu S.; Pacheco A.; Padilla C.; Palla F.; Pascual A.; Perlas J.; Sanchez F.; Teubert F.; Creanza D.; de Palma M.; Farilla A.; Iaselli G.; Maggi G.; Marinelli N.; Natali S.; Nuzzo S.; Ranieri A.; Raso G.; Romano F.; Ruggieri F.; Selvaggi G.; Silvestris L.; Tempesta P.; Zito G.; Huang X.; Lin J.; Ouyang Q.; Wang T.; Xie Y.; Xu R.; Xue S.; Zhang J.; Zhang L.; Zhao W.; Bonvicini G.; Cattaneo M.; Comas P.; Coyle P.; Drevermann H.; Engelhardt A.; Forty R.; Frank M.; Girone M.; Hagelberg R.; Harvey J.; Jacobsen R.; Janot P.; Jost B.; Knobloch J.; Lehraus I.; Maggi M.; Markou C.; Martin E.; Mato P.; Meinhard H.; Minten A.; Miquel R.; Oest T.; Palazzi P.; Pater J.; Perrodo P.; Pusztaszeri J.; Ranjard F.; Rensing P.; Rolandi L.; Schlatter D.; Schmelling M.; Schneider O.; Tejessy W.; Tomalin I.; Venturi A.; Wachsmuth H.; Wiedenmann W.; Wildish T.; Witzeling W.; Wotschack J.; Ajaltouni Z.; Bardadin-Otwinowska M.; Barres A.; Boyer C.; Falvard A.; Gay P.; Guicheney C.; Henrard P.; Jousset J.; Michel B.; Monteil S.; Montret J.; Pallin D.; Perret P.; Podlyski F.; Proriol J.; Rossignol J.; Saadi F.; Fearnley T.; Hansen J.; Hansen J.; Hansen J.; Hansen P.; Nilsson B.; Kyriakis A.; Simopoulou E.; Siotis I.; Vayaki A.; Zachariadou K.; Blondel A.; Bonneaud G.; Brient J.; Bourdon P.; Passalacqua L.; RougĂ© A.; Rumpf M.; Tanaka R.; Valassi A.; Verderi M.; Videau H.; Candlin D.; Parsons M.; Focardi E.; Parrini G.; Corden M.; Delfino M.; Georgiopoulos C.; Jaffe D.; Antonelli A.; Bencivenni G.; Bologna G.; Bossi F.; Campana P.; Capon G.; Cerutti F.; Chiarella V.; Felici G.; Laurelli P.; Mannocchi G.; Murtas F.; Murtas G.; Pepe-Altarelli M.; Dorris S.; Halley A.; ten Have I.; Knowles I.; Lynch J.; Morton W.; O'Shea V.; Raine C.; Reeves P.; Scarr J.; Smith K.; Smith M.; Thompson A.; Thomson F.; Thorn S.; Turnbull R.; Becker U.; Braun O.; Geweniger C.; Graefe G.; Hanke P.; Hepp V.; Kluge E.; Putzer A.; Rensch B.; Schmidt M.; Sommer J.; Stenzel H.; Tittel K.; Werner S.; Wunsch M.; Beuselinck R.; Binnie D.; Cameron W.; Colling D.; Dornan P.; Konstantinidis N.; Moneta L.; Moutoussi A.; Nash J.; San Martin G.; Sedgbeer J.; Stacey A.; Dissertori G.; Girtler P.; Kneringer E.; Kuhn D.; Rudolph G.; Bowdery C.; Brodbeck T.; Colrain P.; Crawford G.; Finch A.; Foster F.; Hughes G.; Sloan T.; Whelan E.; Williams M.; Galla A.; Greene A.; Kleinknecht K.; Quast G.; Raab J.; Renk B.; Sander H.; Wanke R.; Zeitnitz C.; Aubert J.; Bencheikh A.; Benchouk C.; Bonissent A.; Bujosa G.; Calvet D.; Carr J.; Diaconu C.; Etienne F.; Thulasidas M.; Nicod D.; Payre P.; Rousseau D.; Talby M.; Abt I.; Assmann R.; Bauer C.; Blum W.; Brown D.; Dietl H.; Dydak F.; Gotzhein C.; Jakobs K.; Kroha H.; LĂŒtjens G.; Lutz G.; MĂ€nner W.; Moser H.; Richter R.; Rosado-Schlosser A.; Settles R.; Seywerd H.; Stierlin U.; Denis R.; Wolf G.; Alemany R.; Boucrot J.; Callot O.; Cordier A.; Courault F.; Davier M.; Duflot L.; Grivaz J.; Heusse P.; Jacquet M.; Kim D.; Le Diberder F.; Lefrançois J.; Lutz A.; Musolino G.; Nikolic I.; Park H.; Park I.; Schune M.; Simion S.; Veillet J.; Videau I.; Abbaneo D.; Azzurri P.; Bagliesi G.; Batignani G.; Bettarini S.; Bozzi C.; Calderini G.; Carpinelli M.; Ciocci M.; Ciulli V.; Dell'Orso R.; Fantechi R.; Ferrante I.; FoĂ  L.; Forti F.; Giassi A.; Giorgi M.; Gregorio A.; Ligabue F.; Lusiani A.; Marrocchesi P.; Messineo A.; Rizzo G.; Sanguinetti G.; SciabĂ  A.; Spagnolo P.; Steinberger J.; Tenchini R.; Tonelli G.; Triggiani G.; Vannini C.; Verdini P.; Walsh J.; Betteridge A.; Blair G.; Bryant L.; Gao Y.; Green M.; Johnson D.; Medcalf T.; Mir L.; Strong J.; Bertin V.; Botterill D.; Clifft R.; Edgecock T.; Haywood S.; Edwards M.; Maley P.; Norton P.; Thompson J.; Bloch-Devaux B.; Colas P.; Duarte H.; Emery S.; Kozanecki W.; Lançon E.; Lemaire M.; Locci E.; Marx B.; Perez P.; Rander J.; Renardy J.; Rosowsky A.; Roussarie A.; Schuller J.; Schwindling J.; Si Mohand D.; Trabelsi A.; Vallage B.; Johnson R.; Kim H.; Litke A.; McNeil M.; Taylor G.; Beddall A.; Booth C.; Boswell R.; Cartwright S.; Combley F.; Dawson I.; Koksal A.; Letho M.; Newton W.; Rankin C.; Thompson L.; Böhrer A.; Brandt S.; Cowan G.; Feigl E.; Grupen C.; Lutters G.; Minguet-Rodriguez J.; Rivera F.; Saraiva P.; Smolik L.; Stephan F.; Bosisio L.; Della Marina R.; Ganis G.; Giannini G.; Gobbo B.; Pitis L.; Ragusa F.; Rothberg J.; Wasserbaech S.; Armstrong S.; Bellantoni L.; Elmer P.; Feng Z.; Ferguson D.; Gao Y.; GonzĂĄlez S.; Grahl J.; Harton J.; Hayes O.; Hu H.; McNamara P.; Nachtman J.; Orejudos W.; Pan Y.; Saadi Y.; Schmitt M.; Scott I.; Sharma V.; Turk J.; Walsh A.; Weber F.; Wu S.; Wu X.; Yamartino J.; Zheng M.; Zobernig G.; Buskulic D.; Casper D.; Zobernig G.; Buskulic D.</p
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