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L1CaloTrigger Algorithms

L1CaloTrigger Algorithms. Sridhara Dasu University of Wisconsin Algorithms: Details, Updates and Simulation 2 x 10 33 cm -2 s -1 studies (CMS IN 2002/19) Highlights Good jets and H T What will be implemented in GCT/GT Unexplored features - invitation to participate

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L1CaloTrigger Algorithms

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  1. L1CaloTrigger Algorithms • Sridhara Dasu • University of Wisconsin • Algorithms: Details, Updates and Simulation • 2 x 1033 cm-2 s-1 studies (CMS IN 2002/19) • Highlights • Good jets and HT • What will be implemented in GCT/GT • Unexplored features - invitation to participate • Define LUTs etc. in RCT, GCT • Define GT algorithms Sridhara Dasu

  2. Overview GCT BU/PU RCT TPG GT Sridhara Dasu

  3. Calorimeter Geometry EB, EE, HB, HE map to 18 RCT crates Provide e/g and jet, t, ET triggers Sridhara Dasu

  4. Trigger Mapping Sridhara Dasu

  5. Electron/Photon Algorithm Sridhara Dasu

  6. t / Jet Algorithm Sridhara Dasu

  7. 8-bit nonlinear EM ET 7-bit linear ET Lookup table for arbitrary nonlinear transform - including making E+H and H/E Electron 1-bit EM fine-grain bit 1-bit H/E, FG Veto 9-bit linear ET 8-bit nonlinear HD ET Jet / t 1-bit Activity Tower Level Memory LUT • Fully programmable LUT, Current default values: • Electron scale: 0.5 GeV LSB, Emax=63.5 GeV • Veto: OR of fine-grain veto and H / E < 5% • Jet / t scale (E+H): 1.0 GeV LSB, Emax=511 GeV • Jet energy (12x12 tower sum), Emax=1 TeV • Activity level for t pattern: E > 2 GeV, H > 4 GeV Sridhara Dasu

  8. ET18 ET1 ET2 Ex1 Ex2 Ex18 Ey1 Ey2 Ey18 Missing / Total ET Algorithm 360o LUT Strip ET sum over all h For sums ET scale LSB (quantization) ~ 1 GeV is used Df = 20o used instead of HCAL tower size: Df = 5o f …… 40o 20o 0o -5 ET 5 0 h MET Sridhara Dasu

  9. Trigger Rates Vs Threshold Sridhara Dasu

  10. Trigger Efficiency Turn-on Sridhara Dasu

  11. Cal Trigger Rates: 2 x 1033 cm-2 s-1 Selected Scenario: 5 kHz e/g, 5 kHz t,jets, 1 kHz combined, rest m Sridhara Dasu

  12. Physics Efficiency: 2 x 1033 cm-2 s-1 Scenario: 5 kHz e/g, 5 kHz t,jets, 1 kHz comb, rest m No generator level cuts other than requiring trigger objects within calo. (h<5) or tracker (e,g,t) acceptance Sridhara Dasu

  13. Good Jets • L1CaloTrigger finds jets of three types • Central, Forward and t jets • We send GT 4 objects of each type • These are mutually exclusive lists • For pure jet triggers, we need to use objects from all three categories, i.e., combine and re-sort • Although, this is easy to implement in software, we will use too many GT algorithm slots • Use good jet (ET>Threshold) counts • Can count within programmable h cuts • Several counts available • For example: 2 jets in central, 1 in +forward, 1 in -forward • Need simulation studies to define what is useful Sridhara Dasu

  14. HT Trigger • Total scalar ET integrates too much noise and is not easily calibrated • At L1 tower-by-tower ET calibration is not available • However, jet calibration is available as f(ET, h, f) • Therefore, HT which is the sum of scalar ET of all high ET objects in the event is more useful for heavy particle discovery/study • SUSY sparticles • Top • GCT should be able to implement it (FPGAs + flexible backplane) • Use top 8 or 12 candidates in sorted good jet list • Sum ET of good jets with ET>threshold (e.g., 10 GeV) Sridhara Dasu

  15. GCT/GT Algorithm Agreement • HT from GCT to GT on separate cable in same format as ET • Study jet counts with an eye towards increasing numbers and categories • Works on good* jets (ET cut) • *Should include all 3 categories (C + F + ) • Decide by June CMS Trigger Meeting • Jets are calibrated with LUTs • Keep 4 x (C + F + ) = 12 Jet List to GT Sridhara Dasu

  16. Summary • RCT preproduction prototypes implementing the algorithms and programmability as described in this talk are built • The default values for LUTs coded in ORCA perform quite well for discovery physics • Need to further optimize the use of L1 LUTs • GCT will implement good jet counts with cuts on various h and f regions, and HT trigger • Need to explore the use of the jet counts for use in multi-jet physics events • Will help save some GT algorithms • Topological trigger cuts in GT • Jim Brooke started exploring Dh cut for WW fusion • L1 group will be happy to help anyone interested in optimization of cuts to improve trigger performance. Sridhara Dasu

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