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Author Latonova, V. et al; Bernabeu, J.; Lacasta, C.; Solaz, C.; Soldevila, U. doi  openurl
  Title Characterization of the polysilicon resistor in silicon strip sensors for ATLAS inner tracker as a function of temperature, pre- and post-irradiation Type Journal Article
  Year 2023 Publication (down) Nuclear Instruments & Methods in Physics Research A Abbreviated Journal Nucl. Instrum. Methods Phys. Res. A  
  Volume 1050 Issue Pages 168119 - 5pp  
  Keywords HL-LHC; ATLAS ITk; Silicon micro-strip sensor; Polysilicon bias resistor; Testchip  
  Abstract The high luminosity upgrade of the Large Hadron Collider, foreseen for 2029, requires the replacement of the ATLAS Inner Detector with a new all-silicon Inner Tracker (ITk). The expected ultimate total integrated luminosity of 4000 fb(-1) means that the strip part of the ITk detector will be exposed to the total particle fluences and ionizing doses reaching the values of 1.6 center dot 10(15) MeVn(eq)/cm(2) and 0.66MGy, respectively, including a safety factor of 1.5. Radiation hard n(+)-in-p micro-strip sensors were developed by the ATLAS ITk strip collaboration and are produced by Hamamatsu Photonics K.K. The active area of each ITk strip sensor is delimited by the n-implant bias ring, which is connected to each individual n(+) implant strip by a polysilicon bias resistor. The total resistance of the polysilicon bias resistor should be within a specified range to keep all the strips at the same potential, prevent the signal discharge through the grounded bias ring and avoid the readout noise increase. While the polysilicon is a ubiquitous semiconductor material, the fluence and temperature dependence of its resistance is not easily predictable, especially for the tracking detector with the operational temperature significantly below the values typical for commercial microelectronics. Dependence of the resistance of polysilicon bias resistor on the temperature, as well as on the total delivered fluence and ionizing dose, was studied on the specially-designed test structures called ATLAS Testchips, both before and after their irradiation by protons, neutrons, and gammas to the maximal expected fluence and ionizing dose. The resistance has an atypical negative temperature dependence. It is different from silicon, which shows that the grain boundary has a significant contribution to the resistance. We discuss the contributions by parameterizing the activation energy of the polysilicon resistance as a function of the temperature for unirradiated and irradiated ATLAS Testchips.  
  Address [Latonova, V.; Federicova, P.; Kroll, J.; Kvasnicka, J.; Mikestikova, M.] Acad Sci Czech Republ, Inst Phys, Slovance 2, Prague 8, Czech Republic, Email: vera.latonova@cern.ch  
  Corporate Author Thesis  
  Publisher Elsevier Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0168-9002 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:001035405300001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 5601  
Permanent link to this record
 

 
Author Miyagawa, P.S. et al; Bernabeu, P.; Lacasta, C.; Solaz, C.; Soldevila, U. doi  openurl
  Title Analysis of the results from Quality Control tests performed on ATLAS18 Strip Sensors during on-going production Type Journal Article
  Year 2024 Publication (down) Nuclear Instruments & Methods in Physics Research A Abbreviated Journal Nucl. Instrum. Methods Phys. Res. A  
  Volume 1064 Issue Pages 169457 - 9pp  
  Keywords HL-LHC; ATLAS; ITk; Strip sensors  
  Abstract The ATLAS experiment will replace its existing Inner Detector with the new all -silicon Inner Tracker (ITk) to cope with the operating conditions of the forthcoming high -luminosity phase of the LHC (HL-LHC). The outer regions of the ITk will be instrumented with similar to 18000 ATLAS18 strip sensors fabricated by Hamamatsu Photonics K.K. (HPK). With the launch of full-scale sensor production in 2021, the ITk strip sensor community has undertaken quality control (QC) testing of these sensors to ensure compliance with mechanical and electrical specifications agreed with HPK. The testing is conducted at seven QC sites on each of the monthly deliveries of similar to 500 sensors. This contribution will give an overview of the QC procedures and analysis; the tests most likely to determine pass/fail for a sensor are IV, long-term leakage current stability, full strip test and visual inspection. The contribution will then present trends in the results and properties following completion of similar to 60% of production testing. It will also mention challenges overcome through collaborative efforts with HPK during the early phases of production. With less than 5% of sensors rejected by QC testing, the overall production quality has been very good.  
  Address [Miyagawa, P. S.; Beck, G. A.; Bevan, A. J.; Chen, Z.; Dawson, I.; Zenz, S. C.] Queen Mary Univ London, Particle Phys Res Ctr, GO Jones Bldg, Mile End Rd, London E14NS, England, Email: paul.miyagawa@cern.ch  
  Corporate Author Thesis  
  Publisher Elsevier Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0168-9002 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:001249611300001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 6158  
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Author ATLAS Collaboration (Aaboud, M. et al); Alvarez Piqueras, D.; Barranco Navarro, L.; Cabrera Urban, S.; Castillo Gimenez, V.; Cerda Alberich, L.; Costa, M.J.; Fernandez Martinez, P.; Ferrer, A.; Fiorini, L.; Fuster, J.; Garcia, C.; Garcia Navarro, J.E.; Gonzalez de la Hoz, S.; Hernandez Jimenez, Y.; Higon-Rodriguez, E.; Jimenez Pena, J.; King, M.; Lacasta, C.; Lacuesta, V.R.; Mamuzic, J.; Marti-Garcia, S.; Melini, D.; Mitsou, V.A.; Pedraza Lopez, S.; Rodriguez Rodriguez, D.; Romero Adam, E.; Ros, E.; Salt, J.; Sanchez Martinez, V.; Soldevila, U.; Sanchez, J.; Valero, A.; Valls Ferrer, J.A.; Vos, M. url  doi
openurl 
  Title Search for scalar leptoquarks in pp collisions at root s=13TeV with the ATLAS experiment Type Journal Article
  Year 2016 Publication (down) New Journal of Physics Abbreviated Journal New J. Phys.  
  Volume 18 Issue Pages 093016 - 25pp  
  Keywords leptoquark; ATLAS; LHC  
  Abstract An inclusive search for a new-physics signature of lepton-jet resonances has been performed by the ATLAS experiment. Scalar leptoquarks, pair-produced in pp collisions at root s = 13 TeV at the large hadron collider, have been considered. An integrated luminosity of 3.2 fb(-1), corresponding to the full 2015 dataset was used. First (second) generation leptoquarks were sought in events with two electrons (muons) and two or more jets. The observed event yield in each channel is consistent with Standard Model background expectations. The observed (expected) lower limits on the leptoquark mass at 95% confidence level are 1100 and 1050 GeV (1160 and 1040 GeV) for first and second generation leptoquarks, respectively, assuming a branching ratio into a charged lepton and a quark of 100%. Upper limits on the aforementioned branching ratio are also given as a function of leptoquark mass. Compared with the results of earlier ATLAS searches, the sensitivity is increased for leptoquark masses above 860 GeV, and the observed exclusion limits confirm and extend the published results.  
  Address [Jackson, P.; Lee, L.; Petridis, A.; White, M. J.] Univ Adelaide, Dept Phys, Adelaide, SA, Australia  
  Corporate Author Thesis  
  Publisher Iop Publishing Ltd Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1367-2630 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000384093400001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 2828  
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Author Han, X.F.; Wang, L.; Yang, J.M. url  doi
openurl 
  Title Higgs pair signal enhanced in the 2HDM with two degenerate 125 GeV Higgs bosons Type Journal Article
  Year 2016 Publication (down) Modern Physics Letters A Abbreviated Journal Mod. Phys. Lett. A  
  Volume 31 Issue 31 Pages 1650178 - 14pp  
  Keywords Two-Higgs-doublet model; Higgs; LHC  
  Abstract We discuss a scenario of the type-II two-Higgs- doublet model (2HDM) in which the b (b) over bar gamma gamma rate of the Higgs pair production is enhanced due to the two nearly degenerate 125 GeV Higgs bosons ( h, H). Considering various theoretical and experimental constraints, we figure out the allowed ranges of the trilinear couplings of these two Higgs bosons and calculate the signal rate of b (b) over bar gamma gamma from the productions of Higgs pairs (hh, hH, HH) at the large hadron collider (LHC). We find that in the allowed parameter space some trilinear Higgs couplings can be larger than the Standard Model (SM) value by an order and the production rate of b _ b.. can be greatly enhanced. We also consider a “decoupling” benchmark point where the light CP-even Higgs has a SM-like cubic self-coupling while other trilinear couplings are very small. With a detailed simulation on the b (b) over bar gamma gamma signal and backgrounds, we find that in such a “decoupling” scenario the hh and hH channels can jointly enhance the statistical significance to 5 sigma at 14 TeV LHC with an integrated luminosity of 3000 fb(-1).  
  Address [Han, Xiao-Fang; Wang, Lei] Yantai Univ, Dept Phys, Yantai 264005, Peoples R China, Email: leiwang@ytu.edu.cn  
  Corporate Author Thesis  
  Publisher World Scientific Publ Co Pte Ltd Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0217-7323 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000383789300007 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 2817  
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Author Boggia, M.; Cruz-Martinez, J.M.; Frellesvig, H.; Glover, N.; Gomez-Ambrosio, R.; Gonella, G.; Haddad, Y.; Ilnicka, A.; Jones, S.; Kassabov, Z.; Krauss, F.; Megy, T.; Melini, D.; Napoletano, D.; Passarino, G.; Patel, S.; Rodriguez-Vazquez, M.; Wolf, T. url  doi
openurl 
  Title The HiggsTools handbook: a beginners guide to decoding the Higgs sector Type Journal Article
  Year 2018 Publication (down) Journal of Physics G Abbreviated Journal J. Phys. G  
  Volume 45 Issue 6 Pages 065004 - 152pp  
  Keywords LHC physics; Higgs boson; new physics searches; effective field theories; Higgs momentum distributions  
  Abstract This report summarises some of the activities of the HiggsTools initial training network working group in the period 2015-2017. The main goal of this working group was to produce a document discussing various aspects of state-of-the-art Higgs physics at the large hadron collider (LHC) in a pedagogic manner The first part of the report is devoted to a description of phenomenological searches for new physics (NP) at the LHC. All of the available studies of the couplings of the new resonance discovered in 2012 by the ATLAS and CMS experiments (Aad et al (ATLAS Collaboration) 2012 Phys. Lett. B 716 1-29; Chatrchyan et al (CMS Collaboration) 2012 Phys. Lett. B 716 30-61) conclude that it is compatible with the Higgs boson of the standard model (SM) within present precision. So far the LHC experiments have given no direct evidence for any physical phenomena that cannot be described by the SM. As the experimental measurements become more and more precise, there is a pressing need for a consistent framework in which deviations from the SM predictions can be computed precisely. Such a framework should be applicable to measurements in all sectors of particle physics, not only LHC Higgs measurements but also electroweak precision data, etc. We critically review the use of the k-framework, fiducial and simplified template cross sections, effective field theories, pseudoobservables and phenomenological Lagrangians. Some of the concepts presented here are well known and were used already at the time of the large electron-positron collider (LEP) experiment. However, after years of theoretical and experimental development, these techniques have been refined, and we describe new tools that have been introduced in order to improve the comparison between theory and experimental data. In the second part of the report, we propose Phi(eta)* as a new and complementary observable for studying Higgs boson production at large transverse momentum in the case where the Higgs boson decays to two photons. The Phi(eta)* variable depends on measurements of the angular directions and rapidities of the two Higgs decay products rather than the energies, and exploits the information provided by the calorimeter in the detector. We show that, even without tracking information, the experimental resolution for Phi(eta)* is better than that of the transverse momentum of the photon pair, particularly at low transverse momentum. We make a detailed study of the phenomenology of the Phi(eta)* variable, contrasting the behaviour with the Higgs transverse momentum distribution using a variety of theoretical tools including event generators and fixed order perturbative computations. We consider the theoretical uncertainties associated with both p TH and Phi(eta)* distributions. Unlike the transverse momentum distribution, the Phi(eta)* distribution is well predicted using the Higgs effective field theory in which the top quark is integrated out-even at large values of Phi(eta)*-thereby making this a better observable for extracting the parameters of the Higgs interaction. In contrast, the potential of the Phi(eta)* distribution as a probe of NP is rather limited, since although the overall rate is affected by the presence of additional heavy fields, the shape of the Phi(eta)* distribution is relatively insensitive to heavy particle thresholds.  
  Address [Boggia, M.; Gonella, G.; Jones, S.; Megy, T.] Albert Ludwigs Univ Freiburg, Phys Inst, D-79104 Freiburg, Germany, Email: raquel.gomez-ambrosio@durham.ac.uk  
  Corporate Author Thesis  
  Publisher Iop Publishing Ltd Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0954-3899 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000434094000001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 3604  
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