QCD background Full Production Background mimics Higgs -> TauTau signal Two tag Jets One Tau Jet and one electron Tau e- qqqq Higgs Begin by Filtering events to have a background with a Lead jet and Second jet with certain Pt requirements. As well as this we filter for a possible Taujet and electron.
Filter 1Filter 2Filter 3Filter 4 Lead Jet Pt 40304030 Second Jet Pt 20152015 eta gap3.5 3.0 Number of Electrons 49813 Filter Off 90 Filters: 50 000 events generated with each filter
Electron Pt: with and without filter Lead Jet Pt > 30GeV Second Jet Pt > 15GeV eta gap > 3.0 No Filter used
Jet Pt with and without filter Jet 2Jet 1 Jet 3 Jet 4 Black = Filter OFF Green = Hard Filter (ON) Red = Soft Filter (ON)
Jet Eta with and without filter Jet 1Jet 2 Jet 3 Jet 4 Black = Filter OFF Red = Filter ON
Full Production Filter that asks for Lead Jet Pt > 30GeV, Second Jet Pt > 15GeV and eta gap > 3.0 We have at least 10 000 events with filters generated daily (about 5% of events pass filter). About 40GB/day Expect about 52 electrons of which 4-5 have Pt>20GeV to be generated daily.
Results so far… Identifying electrons “hasTrack” and Pt > 20GeV egamma isEM Minimizing background electrons, (while keeping optimum signal) Isolation cut (etcone) E/P restrictions
Identifying Electrons HasTrack Cluster matched to track by: 1) eta and phi at origin of track are compared to eta and phi of cluster. Need 0.05 agreement in eta, 0.1 in phi and E/P < 4 2) Track extrapolated from cluster to origin, at each compartment deltaEta and deltaPhi are calculated. Required to be 0,025 and 0.05 respectively. Egamma Differentiates between egamma object and soft electrons Considers shape of cluster and requires certain energy thresholds
Identifying Electrons isEM A selection tool that considers the following: ClusterEtaRange, ClusterHadronicLeakage, ClusterMiddleSampling, ClusterFirstSampling, TrackEtaRange,TrackHits A0, TrackMatchAndEoP, TrackTRT (not used now) Stricter than egamma, looks closer at the shower shape and track to calorimeter tracking.
Identifying electrons: Pt hasTrack and Pt < 20GeV egammaisEM
Identifying electrons: eta hasTrack and Pt < 20GeV egamma isEM
Identifying Electrons No CutshasTrack & Pt > 20 GeV egammaisEM Number of electrons candidates 1.93646e+06 129223 20372264 % of original candidates 6.67317%1.05202%0.0136332% Number of e- matched to Truth 1.25796e+06 10970517025232 Fake Rate 53.9358% 17.7913%19.6593%13.7931%
Minimizing Background electrons First Reduction by Etcone < 10GeV Secondly: 1.8 < E/P < 1.4 Cut selection minimizes background whilst keeping signal efficiency as high as possible. etcone cutetcone and E/P cut
Minimizing Background hasTrack & Pt > 20GeV egammaisEM etcone < 10GeV etcone<10GeV& 1.8 < E/P < 1.4 Number of electron candidates 129223 20372264 9139 % of original candidates 6.67317%1.05202% 0.0136332%0.00469931%0.00201399% Number of e- matched to Truth 109705170252327935 Fake Rate 17.7913%19.6593%13.7931%15.1899%11.4286%