10/20/06 hard/photon analysis fest 1 measuring bremsstrahlung photons in pp collisions (update) ali...
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10/20/06Hard/Photon Analysis Fest
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Measuring bremsstrahlung photons in pp
collisions (update)
Ali Hanks
Group Meeting
Oct. 16, 2006
10/20/06Hard/Photon Analysis Fest
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Method
• Fragmentation photons are correlated with high pT jets
– Use h- correlations to select photons associated with jets
• Tagging method for estimating decay photon background
– Tag photons from 0 using invariant mass distribution– Estimate tagging efficiency with fastmc
10/20/06Hard/Photon Analysis Fest
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Method (cont’d)
• Associated 0-decay per trigger yield:
• Include contribution from other hadronic decays:
• Associated frag per trigger yield:
10/20/06Hard/Photon Analysis Fest
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h-inc
per trigger yield
10/20/06Hard/Photon Analysis Fest
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h-tagged
per trigger yield
10/20/06Hard/Photon Analysis Fest
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Tagging efficiency
• Simulation generates 0s in a
guassian distribution around a
“trigger” hadron
– distribution is pT dependant
– determined from real data
• Let these 0s decay and compare
resulting h- distribution for
single photon acceptance and pair
acceptance
0
trigger
∆
hadron- ∆ distribution
two particle acceptance
three particle acceptance
10/20/06Hard/Photon Analysis Fest
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0 distribution from data
10/20/06Hard/Photon Analysis Fest
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0 distribution from data
• Use sigma values from fit as input for distributions generated in same pT bins
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Tagging efficiency estimates
• Study tagging efficiency as a function of in same pT bins as data
• Still need to do this with input 0 spectrum from pp
10/20/06Hard/Photon Analysis Fest
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h-tagged
per trigger yield• With estimated tagging efficiency included
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h-subtracted
per trigger yield• h-
inc – h-
tagged with tagging efficiency included
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To Do
• Complete work on subtraction of h-decay
– Study tagging to check for possible over-tagging
– Check esitmate of tagging efficiency for errors
– contribution from other hadronic decays• Still not clear if shape is same as for 0
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Hot tower Maps
• hot towers for cluster with pT from 1-2 GeV/c
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Hot tower Maps
• hot towers for cluster with pT from 2-3 GeV/c
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Hot tower Maps
• hot towers for cluster with pT from 3-20 GeV/c
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Tagging efficiency