Photon Physics activities Higgs activities ATLAS LPNHE group meeting, 2011, Nov. 8th

A common code is shared between Higgs and SM photon analyses to process MC and data with all the needed corrections (energy corrections, various reweightings, Id tools, OQ tools…) and skim the Photon D3PDs. Important step was done to gather all the needed piece of software in a common cvs repository since september All this code is documented in a common Twiki : Many activities concerning performance issues and analysis methods are shared between SMDP and Higgs diphoton analyses (calibration, efficiencies, background decomposition, …)

Since the last LPNHE Scientific Council G. Marchiori became convener of the SMDP analysis group Diphoton xsection paper with 2010 data accepted by PRD (26/09/11) Photon-jet(s) cross-section with 2010 data: supporting note (ATL-COMPHYS ) signed-off by EdBoard, SM approval talk performed « Measurement of the inclusive isolated prompt photon cross-section in pp collisions at sqrt(s)= 7 TeV using 35 pb^-1 of ATLAS data » accepted yesterday in PLB Ongoing work :  -jet cross section with 2010 data : final work on paper ongoing diphoton cross section with 2011 data : Expect 80k tight and isolated photon pairs in 4 fb-1 Study Mγγ, pTγγ, Δφγγ, |cosθ*| in various kinematic regions Compare with NLO theoretical predictions: – Parton-level generators: Diphox(+gamma2MC), ResBos, MCFM – Full simulation MC: Sherpa (ME at LO), PowHeg/Herwig++, to be released by end of 2011) Activities on calorimetric isolation vs pileup See talk by Sandrine later today Activities on 2D fit to get diphoton sample composition using isolation variables Activities on photon efficiencies from data-driven methods

Present Comparison between data driven methods When can we replace fudge factors and efficiencies from MC by data driven ones with lower systematics ?

Since the last LPNHE Scientific Council EPS paper in PLB (accepted 30/08/11) 1.08 fb -1

Get all the tools to do studies from any proposal of improvement to the related impact on limits. Can now run Hfitter in Batch or on the Grid. Contribution to the Internal “HCP note” Acceptance challenge with data and MC Reweighting challenge for MC systematics from background modeling Sample composition with 2D fit method Global resolution function as a function of Higgs Mass for the various categories Interpolated signal yields in various categories mass Limit settings (and bug tracking in Hfitter) Contributions to the “CERN Council” Pub Note Study of jet categories Limit settings with global resolution function and interpolated yields Contributions to Moriond 2012 paper Isolation with improved pileup corrections Isolation with tracks Improved resolution for converted photons Improved calibration using Z  ee and single photon E spectra in each eta bin (  intercalibration) Simultaneous Fit of sample composition and Higgs mass (isolation/brem variables) Improvement of categories definition (jets, Pt_t, …) Data driven efficiencies ? …