PrimEx Accomplishments since January 2005

1
PrimEx Accomplishmentssince January 2005

• 1. The Framework of the Basic Off-Line software
  package has been Developed and ready to use.

2. We have been advanced in all sub-areas of the
data analysis process. but non of
them are finalized yet !!!
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What Needs to be Done ?

• 1. Finalize HYCAL energy calibration and
  reconstruction code
• minimize errors
• nonlinearities
• deterioration in transition and edges
• Short term stability
• Long term stability.

• 2. Finalize position reconstruction code
• minimize errors
• uncertainties at transition and edges

3. Finalize VETO efficiencies
4. Finalize all timing cuts and their
efficiencies

• 5. Finalize photon counting algorithm, including
• tagger efficiency
• beam current leakage (vs. current)
• beam trips
• get flux number for all production runs

3
what needs to be done? (cont.)

• 6. Understand the Effect of Collimator
• from TAC runs
• from beam tuning runs
• from pair spectrometer
• from physics ee-, Compton

7. Extract ee- pair production absolute diff.
cross section, check consistency for all
runs. Check with theory
8. Extract double arm Compton diff. cross
section first for good runs then check
consistency for all runs. Check with theory.

• 9. See if single arm Compton from ?o runs can
  work for
• long term energy calibration (correction)
• normalize ?o to single arm Compton.

4
What needs to be done ? (cont.)
8. We will have two options
a) If the Compton cross section is consistently
correct within a few percent level, then
apply the same cuts, acceptances, and
extract the ?o absolute cross section.

• b) If Compton cross section is not correct then
  normalize the
• ?o cross section to Compton.

5
PrimEx Problems
1. Man power

1. more motivated graduate students on project
   would not harm

b) JLab support to visitors going
b) JLab support to visitors going
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PrimEx Accamplishments (cont.)
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PrimEx Accomplishments(cont.)
8
PrimEx Problems(to be answered in next few
months)

• 1. beam current stability effects of
  beam trips

9
PrimEx Problems(continuation)
2. Collimator effect on photon flux, through beam
position stability.
3. Beam current leakage from Hall C and A, or
tagger efficiency