SM Direct Photons meeting First data analysis : Not so big pressure on photons community (apart for the pi0 stuff) : we took some time to understand the data in terms of proper usage of DQ flag selection proper usage of selection tools like filters and TAGs A lot of work has been done to prepare the analysis code (PhotonAnalysisUtils): interfaced with GoodRunListSelectorTool Real data : dump EM topoclusters + all the associated moments + track activity around the topocluster MC : improvement in the truth-reco matching, each topocluster matched to truth object (useful for pi0 background strudies in MB) 17/12/2009 SM Direct Photons meeting

SM Direct Photons meeting DQ event selection tools: The data quality flags are stored into a database: http://atlas-runquery.cern.ch/ A query to the database will allow you to generate an xml file containing (for each run) the luminosity blocks fulfilling the selection criteria As an example we proposed last week a query like f r 141706+ and mag s and lhc stablebeams t and dq pix,sct,em,til y+ and dq atlgl g Egamma group is now proposing a slightly different query find run 141000+ and dq lar,pix,sct,trtb,trte y+ and dq atlsol,atltor g and mag s and lhc beamenergy 449-451 I would propose to use the egamma selection for the moment : it will probably become stricter in the future Select events in your athena job using the GoodRunListSelectorTool : https://twiki.cern.ch/twiki/bin/viewauth/Atlas/GoodRunsListsTutorial#Default_good_run_list_selection Use of a common and agreed GRL (the one from egamma) I think is really mandatory to avoid confusions!!! set down a twiki to try to exchange information https://twiki.cern.ch/twiki/bin/view/AtlasProtected/PhotonNtupleProductionFirstCollisions#900_GeV_Real_data_runs_and_LBs 17/12/2009 SM Direct Photons meeting

SM Direct Photons meeting Readiness for first data analysis A few hundreds of photon candidates found in the data : from MC the fakes are ~80% Data/MC agreement on shower shapes is in general very nice Use of the shower shapes for signal/background discrimination is probably a bit premature 17/12/2009 SM Direct Photons meeting

SM Direct Photons meeting Readiness for first data : skimming and D2PDs Photon streams, event selection and preparation of the data for the analysis. If you know the exact content of each run the various selections mechanisms needs to be exercised on real data as well : Selection based on TAG files proven on MC datasets Selection based on ELSSI TAG event collection still failing on large datasets (we are in contact with the developers): this solution would allow us to skip the D2PD step! Straightforward and simple photon filter is also available in svn (DPDUtils) Luminosity calculation in the different skimming approaches not really addressed yet with the required attention! 17/12/2009 SM Direct Photons meeting

SM Direct Photons meeting Preparation for 7 TeV collisions Efficiency and purity matrixes in InSituPerformance database : high priority to guarantee the uniformity of our first analyses. Progresses by Valeria No need to mention that these numbers should be discussed and approved by egamma group. Now testing the infrastructure. Efficiencies : agreed solution for first analyses phase 1 : hardcoded numbers from MC for a few basic startup signal definitions. Decouple identification from Isolation (?) IsEM tight + cone (or ring?) isolation (5%) IsEM tight + cone (or ring?) isolation (10%) IsEM tight + track isolation (standard 4 GeV ?) IsEM tight + topoIsolation (10%) phase 2 : start using efficiency from semi-data driven methods like Zee tag and probe (already available in InSituEgammaPerformance) Background contamination : day 0 : numbers from MC in database for the benchmark selections. day > 0 : estimating purity from data and update the matrixes for benchmark longer term : data driven methods as athena tools to estimate the purity for any given selection 17/12/2009 SM Direct Photons meeting

SM Direct Photons meeting Start-up 7 TeV reference cross sections In order to prepare ourself for the first single/double photon analyses agree on a set of common 'reference' cross section plots based on our best guess of what will happen with real data. The idea would be to have independent plots from different persons and then try to share jobOptions/datacards/histograms as soon as the differences are understood. A group of (true and forced) volunteers set up : Inclusive photon cross sections : Bob(Pythia,JetPhox), Claudio(Pythis,JetPhox) Gamma + jet cross section : Sergei (Pythia,Jetphox), Claudio(Pythia, Jetphox) Diphoton cross sections : Haichen(Diphox,Resbos), Yaquan(Diphox,Resbos), Valerio(Pythia,Diphox), Bertrand(Diphox) SetUp (Pythia, JetPhox, Diphox and ResBos) Center of mass energy : 7 TeV kinematic cuts : pt > 25 GeV, abs(eta)<2.37 : acceptance correction for the crack Isolation : 10% in a cone of 0.4 Plots to be prepared : Inclusive gamma : https://twiki.cern.ch/twiki/bin/view/AtlasProtected/SMDirectPhotonsInclusivePhotonCS Diphoton : https://twiki.cern.ch/twiki/bin/view/AtlasProtected/SMDirectDiPhotonCS Gamma + jet : https://twiki.cern.ch/twiki/bin/view/AtlasProtected/SMDirectPhotonsPhotonJetCS 17/12/2009 SM Direct Photons meeting