1 / 39

ATLAS Tau Trigger

ATLAS Tau Trigger.

freja
Télécharger la présentation

ATLAS Tau Trigger

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. ATLAS Tau Trigger Belanger-Champagne, C; Benslama, K; Bosman, M; Brenner, R; Casado, MP; Czyczula, Z; Dam, M; Demers, S; Farrington, S; Igonkina, O; Kalinowski, A; Kanaya, N; Osuna, C; Pérez, E; Ptacek, E; Reinsch; A; Saavedra, A; Sopczak, A; Strom, D; Torrence, E; Tsuno, S; Vorwerk, V; Watson, A; Xella, S X-th International workshop on Tau Lepton Physics Novosibirsk, 22 – 25 Sep, 2008

  2. Contents • LHC start-up • ATLAS experiment • Motivation of tau trigger • ATLAS Trigger and Tau Trigger • Tau Trigger Efficiency from data • Timing measurements • Conclusions

  3. ATLAS first event (10 Sep) ATLAS first event Triggered by L1TAU, L1 Min. Bias and L1JET

  4. LHC project LHC cooldown status (24 Sep):

  5. Expected LHC Performance Latest news: Start-up in spring 2009.

  6. ATLAS experiment

  7. The Underground Cavern at Point-1 for the ATLAS Detector Underground cavern in Point 1 for the ATLAS detector Length= 55 m Width = 32 m Height = 35 m Depth =100 m

  8. ATLAS Collaboration 37 Countries 169 Institutions 2500 Scientific Authors total (1800 with a PhD, for M&O share) Albany, Alberta, NIKHEF Amsterdam, Ankara, LAPP Annecy, Argonne NL, Arizona, UT Arlington, Athens, NTU Athens, Baku, IFAE Barcelona, Belgrade, Bergen, Berkeley LBL and UC, HU Berlin, Bern, Birmingham, UAN Bogota, Bologna, Bonn, Boston, Brandeis, Bratislava/SAS Kosice, Brookhaven NL, Buenos Aires, Bucharest, Cambridge, Carleton, Casablanca/Rabat, CERN, Chinese Cluster, Chicago, Chile, Clermont-Ferrand, Columbia, NBI Copenhagen, Cosenza, AGH UST Cracow, IFJ PAN Cracow, UT Dallas, DESY, Dortmund, TU Dresden, JINR Dubna, Duke, Frascati, Freiburg, Geneva, Genoa, Giessen, Glasgow, Göttingen, LPSC Grenoble, Technion Haifa, Hampton, Harvard, Heidelberg, Hiroshima, Hiroshima IT, Indiana, Innsbruck, Iowa SU, Irvine UC, Istanbul Bogazici, KEK, Kobe, Kyoto, Kyoto UE, Lancaster, UN La Plata, Lecce, Lisbon LIP, Liverpool, Ljubljana, QMW London, RHBNC London, UC London, Lund, UA Madrid, Mainz, Manchester, CPPM Marseille, Massachusetts, MIT, Melbourne, Michigan, Michigan SU, Milano, Minsk NAS, Minsk NCPHEP, Montreal, McGill Montreal, FIAN Moscow, ITEP Moscow, MEPhI Moscow, MSU Moscow, Munich LMU, MPI Munich, Nagasaki IAS, Nagoya, Naples, New Mexico, New York, Nijmegen, BINP Novosibirsk, Ohio SU, Okayama, Oklahoma, Oklahoma SU, Olomouc, Oregon, LAL Orsay, Osaka, Oslo, Oxford, Paris VI and VII, Pavia, Pennsylvania, Pisa, Pittsburgh, CAS Prague, CU Prague, TU Prague, IHEP Protvino, Regina, Ritsumeikan, UFRJ Rio de Janeiro, Rome I, Rome II, Rome III, Rutherford Appleton Laboratory, DAPNIA Saclay, Santa Cruz UC, Sheffield, Shinshu, Siegen, Simon Fraser Burnaby, SLAC, Southern Methodist Dallas, NPI Petersburg, Stockholm, KTH Stockholm, Stony Brook, Sydney, AS Taipei, Tbilisi, Tel Aviv, Thessaloniki, Tokyo ICEPP, Tokyo MU, Toronto, TRIUMF, Tsukuba, Tufts, Udine/ICTP, Uppsala, Urbana UI, Valencia, UBC Vancouver, Victoria, Washington, Weizmann Rehovot, FH Wiener Neustadt, Wisconsin, Wuppertal, Würzburg, Yale, Yerevan 15-April-2008 ATLAS RRB 8

  9. Barrel toroids

  10. Muon spectrometer (barrel) O I M Barrel: 3 independent readouts: I (inner) - M (middle) - O(outer) Chambers alternate with barrel toroids

  11. Calorimetry Tile barrel Tile extended barrel LAr hadronic endcap (HEC) LAr EM endcap (EMEC) LAr EM barrel LAr forward calorimeter (FCAL)

  12. Tracking detectors ~ 6m long, 1.1 m radius Beam pipe Transition Radiation Tracker : TRT Si Strips Tracker : SCT Pixels

  13. Trigger DAQ Calo MuTrCh Other detectors 40 MHz 40 MHz underground (USA15) FE Pipelines D E T R/O LV L1 2.5 ms 75 kHz ROD ROD ROD RoI Lvl1 acc = 75 kHz 120 GB/s Read-Out Drivers 120 GB/s surface (SDX1) RoI data = 1-2% Read-Out Links ROS H L T D A T A F L O W ROB ROB ROB RoI requests ~ 10 ms LVL2 Read-Out Buffers RoI Builder L2 Supervisor ROIB L2SV Read-Out Sub-systems L2N L2 N/work L2 Proc Unit ~2+4 GB/s L2P ~2 kHz Lvl2 acc = ~2 kHz Dataflow Manager EB EBN Event Building N/work ~ sec Event Filter SFI Sub-Farm Input DFM ~4 GB/s Event Builder EFN Event Filter Processors Event Filter N/work EFP EFP EFP EFP EFacc = ~0.2 kHz SFO Sub-Farm Output ~ 200 Hz ~ 300 MB/s ATLAS Trigger

  14. ATLAS contributions • Poster by Z.Czyczula (Copenhagen), “Tau Physics with First Data at ATLAS” • Talks: • M.P.Casado (Barcelona), “ATLAS tau trigger” • F.Sarri (Pisa), “Search of the Higgs boson decaying into tau-leptons at ATLAS” • A.Kalinowski (Univ. of Regina), “Tau Lepton Reconstruction and ID with the ATLAS Detector at LHC”

  15. Tau Trigger Motivation • ATLAS tau trigger aims at selecting hadronic decays of tau leptons, mainly one or three charged pions plus neutrals and one neutrino. • It is difficult due to the high rate and occupancy but increases tremendously the physics potential. More information about tau triger in CERN-OPEN-2008-020

  16. Motivation at 1031cm-2s-1 • Fundamental for W→tn (first source of taus, 200000 with tau15i in 100 pb-1 at 1031cm-2s-1). • Measure: • Cross section s(pp→W)xBR(W→tn). • Leptonic branching fractions of W. • Lepton universality. • Relevant only for very first data at low instantaneous luminosity due to trigger rates. ATLAS preliminary See CERN-OPEN-2008-020

  17. Motivation at 1033cm-2s-1 • Essential in the following studies: • Charged Higgs of Minimal Supersymmetric Standard Model (MSSM) H±→ t n. • In states with more than one lepton, like SM Higgs boson, MSSM neutral Higgs boson, Z’ boson decays, or decay chains in SUSY particles.

  18. Z’→ tt → hh at 800 GeV Trigger: tau35i(*) + met40 ATLAS preliminary ATLAS preliminary Collinear mass distribution for a hadron-hadron final states for a Z’ signal of 800 GeV. (Collinear aproximation: visible products and neutrino travel together.) Reconstructed visible mass distribution for hadron-hadron final states for a Z’ signal of 800 GeV. (*) tauXXi: First part is type of particle, “XX” is the ET threshold, and “i” indicates an isolation requirement in addition.

  19. The first level trigger (L1) finds regions of activity in the detector, and passes this information to the second level trigger (L2). The second level accesses the data in the region of activity determined by L1 (a few percent of the total). The third level trigger (or Event Filter) can also operate in the region determined by L2. ATLAS Trigger: Regions of Interest (RoI)

  20. Level 1 Tau Trigger Dh x Df = 0.1 x 0.1 • Tau Cluster: Energy in the two most energetic neighboring EM towers + the central 2x2 hadronic towers. • EM Isolation: Energy in the isolating ring between 2x2 and 4x4 in the EM calorimeter. • Hadronic Isolation: Energy in the isolating ring between 2x2 and 4x4 in the hadronic calorimeter. |h| < 2.5

  21. Performance of L1 Tau Trigger ATLAS preliminary ATLAS preliminary Efficiencies normalized with respect to offline (optimized to select those tau events which are likely to be reconstructed with the offline tau algorithms). Dijet sample 8<pT<140 GeV

  22. Example: Z t+t- tau15i tau15i + Signature + Iso lation Iso lation tau15 tau15 STEP4 Signature pt> 15GeV pt> 15GeV STEP3 + tau tau Signature time track finding track finding STEP2 Signature tcand tcand + Cluster shape Cluster shape STEP1 L1 seed  + TAU15i TAU15i HLT (L2 + EF) Selection • Basic concepts: • Guided and simultaneous reconstruction (for the different regions of activity) • Each level uses the information of the preceeding level • The reconstruction is done simultaneously for the different regions of activity. • The rejection is applied as soon as possible. • The second level trigger access only a few % of the total amount of data. • In the third level the whole even is also accessible.

  23. Tau HLT Selection L2 selection EF selection Refine (h,f) with the calorimeter and calculate shape variables Similar to L2, but using sophisticated offline algorithms. The whole event and detailed calibrations are available. Determine tracking variables including recalculation of (h,f) Matching of calorimeter cluster and track collection

  24. L2 variables (high energy taus) ATLAS preliminary Calorimeter Tracking ATLAS preliminary

  25. Event Filter variables (high energy taus) ATLAS ATLAS preliminary Calorimeter

  26. Efficiencies per level Efficiencies calculated with respect to the preceeding level.

  27. Efficiency curves ATLAS preliminary ATLAS preliminary tau20i Efficiencies normalized with respect to offline.

  28. Rates per level Rates calculated on QCD background for L= 1031cm-2s-1.

  29. Tau Trigger Menus

  30. Tau Trigger Menu at 1031cm-2s-1

  31. Z→tt: important at 1031 cm-2s-1 • 14000 events with tau15i in 100pb-1 at 1031cm-2s-1. • Measure: • t trigger efficiency in Z→t(h) lepton • t ID efficiency. • Detector calibration: ETmiss & t-jet energy scale determination. • Cross section (SM measurement) ATLAS preliminary See CERN-OPEN-2008-020

  32. Efficiency measurement on data • Z→tt→lep hadron • Tag the lepton (electron or muon) and probe the other side. • Background: top and QCD. • Expect 1200 signal events in 100pb-1 with 30% background. • Do first single tau trigger turn-on curves. 30pb-1 30pb-1

  33. Efficiency measurement on data • tau + MissET trigger with ttbar • Tag 4jet25, study tau decay offline. • Background: hadronic ttbar, single top and QCD. • Expect ~130 signal events in 100pb-1 with ~85 background events. • Strategy to determine combined tau trigger efficiency with first data.

  34. Timing results Timing is important in HLT because it gives latency. If it takes too long, we can not process data! Time in ms, per event Time in ms, per RoI Mean algorithm execution time for each signature of the tau slice. The average execution time of each algorithm remains roughly equal between signatures, while the average total time per event decreases as a result of the lower number of RoIs per event for high energy signatures.

  35. Conclusions • The tau trigger has recorded the first single beam events from the LHC. • The detector and trigger will be commissioned as soon as we have the first collisions. • The tau trigger will be used standalone for high thresholds and in combined mode for low energies. • Hope to have early measurements with tau data and maybe some discoveries next year…

  36. Backup slides

  37. Level 1 Trigger Schematic view of the level 1 trigger Hardware based

  38. Resolution at each level ATLAS Preliminary

  39. Single Tau Trigger Rates Min. bias with s=70mb, lumi 1031cm-2s-1 Only statistical errors

More Related