From: Glen Warren (gwarren_at_anti-spam)
Date: 19-Jun-2003 11:42:36
GEn01 analysis meeting June 18, 2003 ==================================== attended by: Paul, Oscar at UVa Hongguo, Frank, Nikolai and Glen at JLab REPORTS *) Background: Frank has completed binning of background for Q2=1, 4th pass. The overall correction is 0.5%. We discussed the uncertainty, and decided to go with the sigma of the distribution of background over the various runs. It is almost certainly an overestimate, but at 0.2%, it will have no practical impact. *) CEX: Frank has several questions about Marko's CEX number, mostly concerned with exactly how to apply the corrections. Frank has sent Marko an email and is waiting for a response. *) uncertainty in dilution factor: Hongguo compared the rates for different target materials as provided by Nikolai. Hongguo was concerned about the ratio of the proton to neutron rates varying for the different targets. Nikolai commented that this ratio is very clean, so it is probably related to physics. There is about a 20% scaling factor between data and MC (data is larger). Hongguo followed the procedures set out for Q=0.5, and gets an uncertainty of 2.6% in the stick 4 dilution factor. *) Target polarization: Paul investigated the spike in new times for run around 73 minutes. He found that for Q2=1, there are the distribution of the length of the runs spikes around 70-75 minutes. Next, he looked at individual runs, and found that indeed there is a spike in runs around 73 minutes, but once you look on a scale of seconds instead of minutes, you see differences. Glen is satisfied that everything the spike is real. Paul will submit version 9 of the target polarization list. *) paper: no progress. *) model uncertainties: There was a long discussion about the model uncertainties. Nikolai raised the issue that the inclusion of the model uncertainties as Glen proposed may double count errors. The discussion made several circles. Glen, Hongguo, Frank and Nikolai will met on Friday to reach some conclusions. *) Combining stick 3 and Stick 4: We will take the average. The question is how to do the average. We agreed to use sqrt(counts) as the weighting, i.e. <f> = (sqrt(N_3)f_3+sqrt(N_4)f_4) / (sqrt(N_3)+sqrt(N_4)) Donal *) work on paper. *) review surveyors reports are target alignment Glen *) work on paper *) Lead discussion on model uncertainties, kinematic uncertainties, etc. Frank *) accidentals *) complete Q2=0.5 replay *) incorporate CEX correction Hongguo *) kinematic uncertainties
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