Attendees: Ashot, Chao G, Chao P, Dipangkar, Eugene, Li, Maxime, Weizhi, Xinzhan.

Chao Gu will give the Hall-B collaboration talk.



Xinzhan:
GEM efficiency:
Integrated double arm Moller efficiency, after using radial cut and fix of bug, the angle dependence is gone. Now there is a small time dependence and a step.

<TASK> Check if the gas bottle was changed to produce the step, and try to understand the time dependence (maybe from residual moisture).

The ep efficiency vs angle has low statistics at large angle. But efficiency is dropping slightly(~2-3%) at large angles.

Discussion on how to handle large angles. Have to study the different selection method by comparing data and MC. 


Weizhi:
MC calibration results for ep, now mean and width agree very well.
MC calibration results for ee, again mean and width agree well between data and simulation.

Results from test of new Moller generator compared to Gramolin's generator.
The new is consistently is ~2% lower for all cut parameters (Max only). 
There is some dependence on the Min cut parameter, to be investigated further.

<TASK> Chao Peng will send results to Gramolin and get his comments. Also 
get comments from Akusewich.

There is no theta dependence in the difference between the two generators.
Investigating the precision of the numerical simulation.
Comparison of the Born level cross section from the two generators was exactly the same.