[Gdh_lowq2] EG4 Meeting Friday

[Xiaochao Zheng]

Hi all:

Sorry that I missed the meeting this morning. For those who are 
interested, the past week I have extended the yield stability check to 1.1 
GeV runs and have also included the inclusive electron yield in the plot. 
Please see my report page:

http://www.jlab.org/Hall-B/secure/eg4/xiaochao/index_pion.html

Two representative plots are:

(with inclusive electron in sector 6):
http://www.jlab.org/Hall-B/secure/eg4/xiaochao/pion/plots/yield_check/1.1gev_nh3/yield_pip_1.1gev_nh3_nh3b_wincl_grabbed.png

vs. (exclusive e'pi+ yield only)
http://www.jlab.org/Hall-B/secure/eg4/xiaochao/pion/plots/yield_check/1.1gev_nh3/yield_pip_1.1gev_nh3_nh3b.png

>From what I see, when exclusive yield shows in-stability, it's a good 
indication that inclusive yield is also abnormal, but it may not be true 
the other way around.  The main reason could be that the exclusive yield 
include pions from all sectors, so if only sector 6 changes, it won't be 
that obvious in the total excl yield plot.  It could also be that the 
exclusive yield has large statistical errors, which is the case for the 
NH3 target plots listed above.

So I think the "problems" listed on the current stability table is a good 
start to check why those particular runs behave differently from others 
(again, when excl yield is abnormal, it's very likely the incl yield is 
too).  But for inclusive analysis one should definitely also check the 
inclusive electron yield from sector 6 alone, to spot more problems.  So 
far I am not planning to extend the inclusive yield check to the other 
beam energies because it will require re-process all the data on farm. But 
when I run these jobs the next time for other analysis updates, it will be 
straightforward to make the inclusive plots like the 1.1 GeV runs.

Xiaochao
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Assistant Professor, Department of Physics, Univ. of Virginia
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