1. 10/20/06 Hard/Photon Analysis Fest 1 Measuring bremsstrahlung photons in pp collisions (update) Ali Hanks Group Meeting Oct. 16, 2006

2. 10/20/06 Hard/Photon Analysis Fest 2 Method Fragmentation photons are correlated with high p T 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

3. 10/20/06 Hard/Photon Analysis Fest 3 Method (cont’d) Associated   0-decay per trigger yield: Include contribution from other hadronic decays: Associated  frag per trigger yield:

4. 10/20/06 Hard/Photon Analysis Fest 4 h-  inc per trigger yield

5. 10/20/06 Hard/Photon Analysis Fest 5 h-  tagged per trigger yield

6. 10/20/06 Hard/Photon Analysis Fest 6 Tagging efficiency Simulation generates  0 s in a guassian distribution around a “trigger” hadron –distribution is p T dependant –determined from real data Let these  0 s decay and compare resulting h-  distribution for single photon acceptance and pair acceptance 00 trigger  ∆∆ hadron-  ∆  distribution two particle acceptance three particle acceptance

7. 10/20/06 Hard/Photon Analysis Fest 7  0 distribution from data

8. 10/20/06 Hard/Photon Analysis Fest 8  0 distribution from data Use sigma values from fit as input for distributions generated in same p T bins

9. 10/20/06 Hard/Photon Analysis Fest 9 Tagging efficiency estimates Study tagging efficiency as a function of  in same p T bins as data Still need to do this with input  0 spectrum from pp

10. 10/20/06 Hard/Photon Analysis Fest 10 h-  tagged per trigger yield With estimated tagging efficiency included

11. 10/20/06 Hard/Photon Analysis Fest 11 h-  subtracted per trigger yield h-  inc – h-  tagged with tagging efficiency included

12. 10/20/06 Hard/Photon Analysis Fest 12 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

13. 10/20/06 Hard/Photon Analysis Fest 13 Hot tower Maps hot towers for cluster with p T from 1-2 GeV/c

14. 10/20/06 Hard/Photon Analysis Fest 14 Hot tower Maps hot towers for cluster with p T from 2-3 GeV/c

15. 10/20/06 Hard/Photon Analysis Fest 15 Hot tower Maps hot towers for cluster with p T from 3-20 GeV/c

16. 10/20/06 Hard/Photon Analysis Fest 16 Tagging efficiency