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Partikeldagarna 2013

Overview of ATLAS Activities at Stockholm University Christophe Clément on behalf of the ATLAS SU group Partikeldagarna –Lund 2013. 2013-10-21. Partikeldagarna 2013. 1. ATLAS Research Activities since last Partikeldagarna. Detector activities

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Partikeldagarna 2013

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  1. Overview of ATLAS Activities at Stockholm University Christophe Clément on behalf of the ATLAS SU group Partikeldagarna –Lund 2013 2013-10-21 Partikeldagarna 2013 1

  2. ATLAS Research Activities since last Partikeldagarna Detector activities Calorimeter calibration (see Olga Bessidskaia’s talk) Calorimeter pile-up (see Simon Molander’s talk) Shifts ATLAS Upgrade L1 Calorimeter trigger Tile calorimeter demonstrator Physics Analysis Investigation of the ttZ vertex Search for stop squarks Search for SUSY weak production (see Maja Tylmad’s talk) Search for Dark Matter and Extra dimensions (see Olle Lundberg’s talk ) Search for heavy metastable particles 2013-10-21 Partikeldagarna 2013 2

  3. ATLAS Upgrade Activities and LHC future Target very large datasets To access rare processes Higgs, Beyond SM physics Rare Standard Model processes Cross Section [pb] 100 event per L=1000 fb-1 2013-10-21 Partikeldagarna 2013 3

  4. ATLAS Upgrade Activities and LHC future <μ> = # simultaneous collisions For more details see ECFA High Luminosity LHC Experiments Workshop http://indico.cern.ch/conferenceOtherViews.py?view=standard&confId=252045 in particular F. Bordry’s talk. See alsohttp://hilumilhc.web.cern.ch/HiLumiLHC/index.html 2013-10-21 Partikeldagarna 2013 4

  5. ATLAS Calorimeters 1) Digital precision read-out for physics 2) Analogue “summary” read out for trigger decisions (L1 trigger examines 40 MHz collisions) 2013-10-21 Partikeldagarna 2013 5

  6. Phase 1 Improve L1 Trigger capability to cope with higher particle rates! (beyond LHC design) Increased Calorimeter trigger granularity –> significant improvement of e/ jet selections at 40 MHz. 2013-10-21 Partikeldagarna 2013 6

  7. ATLAS Level-1 Calorimeter Trigger Sam Silverstein is hardware/firmware coordinator for LS1 upgrade projects. Major firmware contributions Sam Silverstein PawelPlucinski Upgrade Jet-processing data path (Pawel) How to use L1Topo + facilities for simulation (Sam) New L1Topo combines information (E, direction) from several objects Fast packing and transmission to L1Topo (Pawel) FPGA-based digital filter 2013-10-21 Partikeldagarna 2013 7

  8. Prepare for <μ>=200 Replace >15 years old electronics Fully digital trigger information readout for new trigger architecture. 2013-10-21 Partikeldagarna 2013 8

  9. TileCal Phase II Upgrade and Demonstrator Effort lead by C. Bohm Present system analogue simplified read-out used for decisions at 40MHz digital read-out full precision for physics Read-out 7 digits if pass L1-trigger Phase II upgraded system Full readout of all data – require high bandwidth optical communication All digital and all digits new handles against pile-up 2013-10-21 Partikeldagarna 2013 9

  10. The Demonstrator Project SU is developing the link DaughterBoard Present adder board (Rio) sROD (Valencia) MainBoard (Chicago) FE boards (Chicago) HV-system (Argonne) LVPS (Argonne) Prototype DaugterBoard Prototype MainBoard sROD emulator Prototype DaughterBoard Front-end board (U Chicago) Hybrid system A upgraded system masquerading as a present system (same inputs and outputs) On track to be inserted into ATLAS in mid 2014 Testbench (Stockholm) 2013-10-21 Partikeldagarna 2013 10

  11. Physics Analysis Activities 2013-10-21 Partikeldagarna 2013 11

  12. Measuring the ttZ cross-section • Sensitive to new physics, background to ttH • Long term goal –> constrain the ttZvertex • Complicated final state • 3 leptons, 4 jets, 2 b-jets, ETmiss • tZis the largest background, but for the vertex constraint tZ is a signal. • 2nd, 3rd largest backgrounds: WZbb, fake lepton • SU People involved • H. Khandanyan, J. Sjölin (editor), O. Bessidskaia, S. Hellman, S. Molander. • Aim for 3 sigma observation with 2012 data Campbell, Ellis, Röntsch Phys. Rev D.87.114006 2013-10-21 Partikeldagarna 2013 12

  13. Direct Stop Quark Production Higgs mass and hierarchy problem most sensitive to the top quark mass. Critical that a light stop quark exists if SUSY is to solve the hierarchy problem. Direct stop searches in ATLAS are mainly based on simplified models (only specify the decay chains, cannot connect with non-LHC experiments). fermion loop S. Strandberg, A. Yiming: study Phenomenological MSSM (pMSSM) –> More realistic scenarios longer, multiple decay chains. What is the current sensitivity to these models? Improve on current ATLAS signal regions? 2013-10-21 Partikeldagarna 2013 13

  14. b-tagging performance at high pT • The identification of bottom quarks (b-tagging) is an important tool in many physics analyses. • The efficiency and fake rate of each algorithm must be calibrated with data. • Current efficiency calibration in ATLAS extends to 300 GeV. • Many physics analyses use jets at much larger pT. • S. Strandberg, A. Shcherbakova: • Develop methods to calibrate b-tagging performance at larger values of jet pT. • Also involved in other b-tagging activities, such as software development. Algorithm name “MV1” 70% efficiency working point. 2013-10-21 Partikeldagarna 2013 14

  15. Long-livedParticleSearches • K. Bendtz, H. Kim, D. Milstead • Massive long-livedparticlesaccommodated in mostmodelsof new physics • R-parity violating Violating SUSY scenario (Lepton and / or Baryon number violation) Displaced decay vertex (DV) 2013-10-21 Partikeldagarna 2013 15

  16. Long-livedParticleSearches • K. Bendtz, H. Kim, D. Milstead • Massive long-livedparticlesaccommodated in mostmodelsof new physics • R-parity violating Violating SUSY scenario (Lepton and / or Baryon number violation) Displaced decay vertex (DV) Displaced vertex reconstruction efficiency z ATLAS Inner Detector 2013-10-21 Partikeldagarna 2013 16

  17. Long-livedParticleSearches (2) • Recent analyses • 2011 data: Phys.Lett. B719 (2013) 280-298) • 2012 data ATLAS public conference record: ATLAS-CONF-2013-092. • Highmass, highmultiplicity • Ongoingwork: MET+DV and highlychargedparticlesearches 2013-10-21 Partikeldagarna 2013 17

  18. Search for Supersymmetry Weak Production C. Clément, P. Klimek, A. Petridis, M. Tylmad. + Probe SUSY if the squarks / gluinos are much heavier. + Independent on squark / gluino mass, generally limited to a few parameters + Address/constrain directly SUSY gaugino sector (Dark Matter) Monte Carlo Simulation LHC 8 TeV “slepton” Use same signal region Standard model lives below 90 GeV 2013-10-21 Partikeldagarna 2013 18

  19. Search for Supersymmetry Weak Production New result since last year 2011 data Phys. Lett. B 718, 3, 879-901 (last year as arXiv:1208.2884) 2012 data Public Conference Record ATLAS-CONF-2013-049 (e/μ), ATLAS-CONF-2013-028 (τh) New channels “stau” “WZ” SU Contributions to these analyses Simulation and choice of models (sleptons, staus), Optimisation of Missing energy and jet definitions (all except tau analysis) Top quark veto (all) Signal region definitions, data driven backgrounds Z+W/Z, Z+jets: (slepton, WZ) See M. Tylmad’s talk. 2013-10-21 Partikeldagarna 2013 19

  20. Search for WIMPS and Extra - Dimensions C. Clément, O. Lundberg, V. Rossetti • Look for invisible particles recoiling against a jet. • WIMPs, extra-dimensions, invisible Higgs… • Our contributions: • main background calculation, limit settings Detector p p need to look for excess over backgrounds hadron jet Perhaps the most competitive tool to search for low mass WIMPS See Olle Lundberg’s talk. 2013-10-21 Partikeldagarna 2013 20

  21. Conclusions • The group is at full speed into the Physics analysis effort with 2012 data • … top, stop, dark matter, ed, susy. Only a sample shown today. • Continues to contribute to fine calibration and studies of the calorimeter • Expanding the efforts towards the ATLAS and LHC upgrade. Postdocs H. Khandanyan H. Kim A. Petridis P. Plucinski V. Rossetti Senior Staff C. Bohm (emer.) C. Clement S. Hellman K. Jon-And D. Milstead T. Moa S. Silverstein S. Strandberg B. Åsman PhD students K. Bendtz G. Bertoli O. Bessidskaia W. Cribbs O. Floren P. Klimek O. Lundberg S. Molander A. Shcherbakova M. Tylmad A. Yiming H. Åkerstedt ATLAS at Stockholm U. spread over two research departments Instrumentation physics Particle Physics 2013-10-21 Partikeldagarna 2013 21

  22. Backup Slides 2013-10-21 Partikeldagarna 2013 22

  23. TileCal Phase II Upgrade and Demonstrator Present system Need to be upgraded to cope with old age, higher reliability and higher luminosity Bohm et al. Phase II upgraded system Full readout of all data – require high bandwidth optical communication TileCal Phase II Upgrade and Demonstrator Hybrid system A upgraded system masquerading as a present system (same inputs and outputs) to be able to be inserted into ATLAS in mid 2014 2013-10-21 Partikeldagarna 2013 23

  24. The Demonstrator Project SU is developing the link DaughterBoard Present adder board (Rio) sROD (Valencia) MainBoard (Chicago) FE boards (Chicago) HV-system (Argonne) LVPS (Argonne) Prototype DaugterBoard Prototype MainBoard sROD emulator Prototype DaughterBoard Front-end board (U Chicago) Schedule Testbench (Stockholm) 2013-10-21 Partikeldagarna 2013 24

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