1. PrimEx Pair Production
Dan Dale
Idaho State University
February 19, 2012

2. Theoretical calculations provided by A. Korchin
Bethe Heitler mechanism with two atomic form factors – Fermi-Moliere and Hartree-Fock
Pair production in the electron field
QED radiative corrections
Nuclear incoherent
Nuclear coherent or VCS

3. Dependence on Atomic Form Factor

4. Set up

5. Compton events subtracted off using GEANT
Fig 7.22

6. “Theory” (black) is events generated by theory, and then plugged into GEANT:

14. Some comments Pair production is a test of flux x target thickness
Integration over x ensures little dependence on HYCAL reconstruction issues
For calculational reasons, we focused on single arm
Excellent agreement with theory – beter than 1%
Target date for publication draft June 2012