1. Basic Trigger Rates December 3, 2004

2. References • Physics and Detector Performance TDR http://www.cern.ch/Atlas/GROUPS/PHYSICS/TDR/physics_tdr/printout/Volume_I.pdf http://www.cern.ch/Atlas/GROUPS/PHYSICS/TDR/physics_tdr/printout/Volume_II.pdf • High Level Trigger…. TDR http://atlas-proj-hltdaqdcs-tdr.web.cern.ch/atlas-proj-hltdaqdcs-tdr/ • Level 1 Trigger TDR http://atlasinfo.cern.ch/Atlas/GROUPS/DAQTRIG/TDR/V1REV1/L1TDR_all.pdf • Comparison of ATLAS and CMS Trigger Rates http://agenda.cern.ch/askArchive.php?base=agenda&categ=a01941&id=a01941s22t3/transparencies • High Level Trigger…LHCC Review June 2004 http://agenda.cern.ch/askArchive.php?base=agenda&categ=a041899&id=a041899s1t7%2Ftransparencies%2Fhlt_final.ppt • ATLAS Trigger Menus for the LHC Start-up Phase http://doc.cern.ch//archive/electronic/cern/others/atlnot/Note/daq/daq-2003-004.pdf • From the ancient days…Supercollider Physics, EHLQ, Reviews of Modern Physics, Vol. 56, No. 4, October 1984

3. Goal • Introduction • Nomenclature • Basic rates • Electrons • Muons • Jets • Etc

4. Very Rough Idea of Rates • Old plot • Remember there are uncertainties in the cross sections • I have not been able to find a recent compilation of relevant cross section predictions…this would be useful to have • Apologies for quality of some graphs…

5. From Physics TDR

6. Level-1 Hardware trigger 75 kHz 2 μs High Level Triggers (HLT) Level-2 + Event Filter Software trigger Target processing time ~ 2 kHz ~ 10 ms ~ 200 Hz ~ 2 s Rate Trigger Concept and Definition

7. Event Filter HLTSSW Processing HLT Core Software Task Steering Monitoring Service HLT Algorithms L2PU Application Data Manager HLT Algorithms ROB Data Collector Event Data Model MetaData Service <<import>> <<import>> <<import>> <<import>> Package Athena/ Gaudi Event Data Model Reconstr. Algorithms StoreGate Interface Offline Reconstruction Offline Core Software Dependency High Level Trigger(HLT) HLT Data Flow Software HLT Selection Software • Framework ATHENA/GAUDI • Reuse offline components • Common to Level-2 and EF Level2 Offline algorithms used in EF

8. Trigger Selection Example Muon LVL1 muon LVL2 muon LVL2 calo isol LVL2 tracking EF muon EF calo isol EF tracking

9. HLT Trigger Objects Wont talk about these Note 2x1033 is the nominal max luminosity for the initial running…optimistic

10. HLT Nomenclature From the HLT TDR, section 4.4 In the subsequent sections, the use of labels with the form ‘NoXXi’ to identify specific trigger items will be used. The meaning of the labels is the following: ‘o’ indicates the type of the selection (‘e’ for electron, ‘γ’ for photon, ‘µ’ for muon, ‘τ’ for a τ hadron, ‘j’ for jet, ‘b’ for a b-tagged jet, ‘xE’ for missing transverse energy, ‘E’ for total transverse energy and ‘jE’ for the total transverse energy obtained using only jets); ‘XX’ gives the threshold in transverse energy (in units of GeV); ‘N’ the number of objects; and ‘i’ indicates an isolation requirement. As an example, 2µ20i refers to the requirement of two muons, with a pT threshold of 20 GeV each, fulfilling isolation criteria. The thresholds indicate the true value above which the selection has good efficiency. The exact value for the efficiency obtained depends on the implementation of the algorithm and the details of the criteria applied. Note that there is a different, but similar, nomenclature for the LVL1 trigger objects.

12. Efficiency Example

13. Single Electrons/Photons LVL1 The rate of the LVL1 electron/photon triggers is dominated by misidentified jets. The ET-threshold scale in the plot is defined so that the efficiency for selecting genuine electrons with transverse energy equal to the quoted value is 95%.

14. Electron/photon pairs LVL1

15. Getting HLT Rate From HLT TDR Update this year e25i Fraction of final rate

16. Muons

17. Muon Cross Sections

19. Jets

20. More Jets

21. Jet Rates

22. Missing ET + 1 jet

23. SUSY Example • Ongoing studies of full simulation of SUSY events in “co-annihilation region”. • See recent talks by Pavel http://agenda.cern.ch/askArchive.php?base=agenda&categ=a045055&id=a045055s1t1%2Ftransparencies%2FNovember_18.ppt • Or Davide http://agenda.cern.ch/askArchive.php?base=agenda&categ=a044275&id=a044275s6t8/transparencies • Soft leptons – see next page • Desire to trigger on these events with missing ET+1jet trigger

24. Lepton Spectra pT for leading and soft electrons pT for leading and soft muons leading e soft e leading muon soft muon pT distribution for leading and soft electrons that are used to calculate dilepton invariant mass. pT distribution for leading and soft muons that are used to calculate dilepton invariant mass.

25. SUSY Example j70 + xE70 j400, 3j165, 4j110

26. Possible Future Topics? • Trigger algorithms for specific objects eg. what is an electron • Just reading but educational • Straightforward to do from various TDRs and presentations • Cross sections and simple spectra (ds/dET) • Many pieces, each by someone? • Generators, simulation….needed • Non-trivial amount of work….need to understand better what is already done or underway