R.Blair, S.Chekanov, R.Norberg, M.Stockton, plus the Direct Photon group
Public results ATLAS-CONF-2013-02
Current CDS note: http://cdsweb.cern.ch/record/1453853
The current note is located here: https://svnweb.cern.ch/trac/atlasphys/browser/Physics/StandardModel/PromptPhotons/Notes/InclusivePhotons3fb How to get and work with it:
(or just kinit <username>@CERN.CH). Then find the note:
Getting the note:
svn co $SVNROOT
This will create a directory “InclusivePhotons3fb”. “cd” into it and compile the package “make”. Always make sure that you keep the most recent directory “svn update”.
Modify a file, then do “svn ci” and put notes. To remove a file, use “svn remove file”. To add file, use “svn add file”.
Read here howto use SVN: https://twiki.cern.ch/twiki/bin/viewauth/Atlas/SoftwareDevelopmentWorkBookSVN
The current note is located here: [[https://svnweb.cern.ch/trac/atlasusr/browser/chekanov/Physics/Photons/Notes/InclusivePhotons2011]] How to get and work with it: Outside CERN: /usr/kerberos/bin/kinit <username>@CERN.CH export SVNUSR="svn+ssh://svn.cern.ch/reps/atlasusr/chekanov" Getting the note: svn co $SVNUSR/Physics//Photons/Notes/InclusivePhotons2011 This will create a directory "InclusivePhotons2011". "cd" into it and compile the package "make". Always make sure that you keep the most recent directory "svn update". Modify a file, then do "svn ci" and put notes. To remove a file, use "svn remove file". To add file, use "svn add file". Read here howto use SVN: [[https://twiki.cern.ch/twiki/bin/viewauth/Atlas/SoftwareDevelopmentWorkBookSVN]]
Systematical and statistical errors added in guadrature.
Green bads shows the renormalisation scale uncertanty plus PDF uncertainties from 52 eigenvectors of CT10 PDF. Yellow-gray band shows the renormalisation uncertanty only.
Here is a plot with 2010 cross sections (extended to 25 GeV)
We follow the general recommendations described here
Current selection cuts:
iLumiCalc.exe –lumitag=OflLumi-7TeV-002 –livetrigger=L1_EM14 –trigger=None –xml=/tmp/lumifiles/795b77/data11_7TeV.periodAllYear_DetStatus-v18-pro08-05_CoolRunQuery-00-03-98_GammaJet.xml
HERWIG simulation (only for systematics on efficiency)
All samples are weighted according to their cross sections and generated efficiencies
General MC status is given here
MC simulations include pile-up as shown in this figure: det_nPV.eps.png
Isolation in bins of pT
Isolations for signal and background
Detector level pT in the region A and D
Look also at the background region:
Detector level pT after the side-band backgroud subtraction. We use a simple backgrown subtraction (non-correlated) due to small statistics for MC. We use correlated quadrant method as systematics.
The tables below show the contributions of each systematic variation in % to the total cross section:
The total systematic uncertainty is calculated by addeding all uncertainties in quadrature.
Bin-by-bin correction factors are defined as C= N(true photons after isolation)/N(reconstructed in the region A). The efficiency is 1/C.
Purity is defined as N(after bkg subtraction)/N(region A).
This measurement is based on the inclusive analysis above by adding a antiKT4 jet.
* det_gamma_jet_mass.eps.png - M(gamma+jet) using the quadrand A for photons
The JETPHOX predictions are based on the JETPHOX V1.3 (ROOT-based) generating ROOT ntuples using the pT ranges as for the final plots. This technique is descibed on the CERN Twiki
4 different JETPHOX ntuples were generated. First sample has 44 PDF sets, 2 other are used to estimate PDF and scale variations, changing one scale at the time. Additional sample was generated by changing the scale and PDF scales coherently.
PDF uncertainties are calculated by taking a max deviation from the central value.
Scale uncertanties were estimated by considering the largest deviation from the central value using different combinations of the scale and PDF uncertainties.
Here are the cuts:
All figure are here: All figures
Root files and tables are available here: All root files
Jetphox prediction: here
Direct-photon group: https://twiki.cern.ch/twiki/bin/view/AtlasProtected/SMDirectPhotons
— Sergei Chekanov 2011/09/02 22:07