1 / 12

High Level Trigger Studies for the ATLAS Detector Efstathios (Stathis) Stefanidis

High Level Trigger Studies for the ATLAS Detector Efstathios (Stathis) Stefanidis 1 st Year Transfer Report, University College London. OUTLINE. The ATLAS Detector : Overview. The Trigger System. Overview. High Level Trigger. Performance Studies. IDScan. e/ γ vertical slice.

huela
Download Presentation

High Level Trigger Studies for the ATLAS Detector Efstathios (Stathis) Stefanidis

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. High Level Trigger Studies for the ATLAS Detector Efstathios (Stathis) Stefanidis 1st Year Transfer Report, University College London Stefanidis E.

  2. OUTLINE • The ATLAS Detector : Overview. • The Trigger System. • Overview. • High Level Trigger. • Performance Studies. • IDScan. • e/γ vertical slice. • RoI size. • Future Plans. Stefanidis E.

  3. The ATLAS Detector: Overview. • pp colliding beams 14 TeV c.m. energy. • Design Luminosity: L=1034 cm-2s-1. • Three Parts: • Inner Detector • Calorimeter (EM – HAD) • Muon Spectrometer • Magnet System: • Solenoid: 2 T • Toroid: 0.4 T Stefanidis E.

  4. High Level Trigger (HLT) The Trigger System: Overview. • LVL1: • 40 MHz  75 kHz • < 2.5 μs • Hardware trigger • Reduced granularity information • LVL2: • 75 kHz  2 kHz • 10 ms • Full granularity information from both ID and Calorimeter • RoI mechanism • Event Filter (EF): • 2 kHz  100 Hz •  2s • Sophisticated algorithms • Alignment data available Stefanidis E.

  5. The Trigger System: HLT. • Event Selection Strategy: • Signature validation • Checks for signatures coming from interesting physics events • REJECT UNINTERESTING EVENTS VERY EARLY • RoI mechanism • (i) Defines the area where HLT • will start from. • (ii) Seeded by LVL1 • (iii) Only the data needed are • transferred •  MINIMISE THE PROCESSING TIME AND NETWORK TRAFFIC Stefanidis E.

  6. Hit Filter Group Cleaner z-Finder Track Fitter The Trigger System: HLT. • Event Selection Software: • ATHENA • Written using GAUDI architecture • Provides common services (Transient Data Store, Histograms, Auditing etc) • Well-defined interface not only to developers but also to the end-users • IMPROVE COHERENCY OF THE DIFFERENT SOFTWARE DOMAINS • IDScan • LVL2 track reconstruction algorithm • SPACE POINTS as input – Track parameters as output • Runs several times per event and once per RoI Stefanidis E.

  7. I. σ=179.9 μm II. III. Total Efficiency Efficiency: |Zgen – Zrec | < 1 mm Performance Studies: IDScan. z-Finder Stefanidis E.

  8. Performance Studies: IDScan. Pattern Recognition • |pTgen – pTrec|<15 GeV • |ηgen – ηrec|<0.01 • |φgen – φrec|<0.01 rads Stefanidis E.

  9. Electron selection • Weνe sample 22.5 GeV Performance Studies: e/γ slice. • Determine selection efficiencies and rates at each Trigger Level. • Apply isolation, energy, tracking matching etc cuts. Stefanidis E.

  10. Performance Studies: RoI size. • Preliminary study • Current size of RoI: ΔηxΔφ = 0.2x0.2 • COULD IT BE LESS ?  Reduce requested data + processing time Stefanidis E.

  11. η resolution: STRONG DEPENDENCE ON Z POSITION OF VERTEX ! ! ! φ resolution: 3mrad Cut at z  2 mm Barrel: σZ =0.86 cm EndCap: σρ =0.35 cm Performance Studies: RoI size. Stefanidis E.

  12. Physics Studies • Low Mass Higgs (mH<150 GeV) • Hγγ • Hbb • Study the full production/simulation/reconstruction chain. Future Plans. • Performance Studies • IDScan : Optimize the size the RoI • e/γ analysis : Improve, validate, optimize the cuts • 2004 TestBeam : Study the timing perfomance Stefanidis E.

More Related