M. Gilchriese Basic Trigger Rates December 3, 2004

M. Gilchriese 2 References Physics and Detector Performance TDR High Level Trigger…. TDR Level 1 Trigger TDR Comparison of ATLAS and CMS Trigger Rates High Level Trigger…LHCC Review June ATLAS Trigger Menus for the LHC Start-up Phase From the ancient days…Supercollider Physics, EHLQ, Reviews of Modern Physics, Vol. 56, No. 4, October 1984

M. Gilchriese 3 Goal Introduction Nomenclature Basic rates –Electrons –Muons –Jets –Etc

M. Gilchriese 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…

M. Gilchriese 5 From Physics TDR

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

M. Gilchriese 7 High Level Trigger(HLT) Level2 HLT Data Flow Software HLT Selection Software  Framework ATHENA/GAUDI  Reuse offline components  Common to Level-2 and EF Offline algorithms used in EF

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

M. Gilchriese 9 HLT Trigger Objects Selection2x10 33 cm -2 s -1 Rates (Hz) Electrone25i, 2e15i ~40 Photon  60i, 2  20i ~40 Muon  20i, 2  10 ~40 Jetsj400, 3j165, 4j110 ~25 Jet & E T miss j70 + xE70 ~20 tau & E T miss  35 + xE45 ~5 b-physics 2  6 with m B /m J/  ~10 Otherspre-scales, calibration, … ~20 Total ~200 Wont talk about these Note 2x10 33 is the nominal max luminosity for the initial running…optimistic

M. Gilchriese 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.

M. Gilchriese 11

M. Gilchriese 12 Efficiency Example

M. Gilchriese 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%.

M. Gilchriese 14 Electron/photon pairs LVL1

M. Gilchriese 15 Getting HLT Rate OriginContribution e from b,c decays25 % e from conversion17 % W  e decays 17 % Z  ee decays 7 % others34 % From HLT TDR Update this year e25i Fraction of final rate

M. Gilchriese 16 Muons

M. Gilchriese 17 Muon Cross Sections

M. Gilchriese 18

M. Gilchriese 19 Jets

M. Gilchriese 20 More Jets

M. Gilchriese 21 Jet Rates

M. Gilchriese 22 Missing ET + 1 jet

M. Gilchriese 23 SUSY Example Ongoing studies of full simulation of SUSY events in “co- annihilation region”. See recent talks by Pavel Or Davide Soft leptons – see next page Desire to trigger on these events with missing ET+1jet trigger

M. Gilchriese 24 Lepton Spectra p T distribution for leading and soft electrons that are used to calculate dilepton invariant mass. p T distribution for leading and soft muons that are used to calculate dilepton invariant mass. leading e soft e leading muon soft muon p T for leading and soft electronsp T for leading and soft muons

M. Gilchriese 25 SUSY Example Event#xEJet 1Jet 2Jet 3Jet j70 + xE70j400, 3j165, 4j110

M. Gilchriese 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 (d  dE T ) –Many pieces, each by someone? –Generators, simulation….needed –Non-trivial amount of work….need to understand better what is already done or underway