[Frost] Incident photon corrections

[Michael Dugger]

Hi,

I apologize for missing the meeting this week. I messed up the time, I 
got it in my head that the meeting started at 8:30 Arizona time.

I looked at the presentation by Sung. It looks like CMU and FSU are in 
good agreement for the CH2 target for photons with energies up to 0.8 of 
the incident electron energy :)

The scale on the plots is too large, this makes it hard to check the 
comparison. With that said, it looks to me like FSU is getting an energy 
correction for the Butanol target that is close to what they get for the 
CH2 target. This is VERY important. We can not have a z-vertex dependence 
in the incident photon energy.

My current hope is that FSU Butanol results are right, and that CMU, and 
ASU Butanol results are wrong. As a check, it would be good to see pull 
distributions and pi0 masses for each target (after energy and momentum 
corrections are applied). For the pi0 mass, it may be important to 
restrict events to have proton phase-space where the vertex looks 
reasonable.

If the FSU results have a good pi0 mass (from the reaction gamma p -> p 
pi0), and the pulls look good, we may be close to having the energy and 
momentum corrections :)

Take care,
Michael