Hall C Jan05 (JLAB experiments E02-109 and E04-001):

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  Analysis Meeting 2 (4/06/05)

1) Plotted efficiency graphs for Calorimeter, Cerenkov, and Tracking from new
calibrated data.  All efficiencies showed improvement except Tracking which we
analyzed further by plotting against W^2.   

2) Works in progress 

Efficiencies

For previous results, see meeting01.

Cerenkov Efficiency

The cuts applied here were:

Ecalo/E' > 1.05
Cer > 2

Here the Cerenkov distribution is shown before and after we cut out the pions at 2
and obtained a clean electron sample using the calorimeter cut.
 



The actual Cerenkov Electron Efficiency is then calculated by:

Eff(Cer) = Events ( Cer >2 & Ecalo/E' > 1.05) / Events (Ecalo/E'>1.05)

Calorimeter Efficiency


To obtain a good electron sample we apply a cut of Cer >8 and 
show the line of the cut where Calorimeter > 0.7





Plot of both particle ID cuts taken simultaneously with Calorimeter vs. Cerenkov distributions



Our formula for Calorimeter Electron Efficiency is then:

Eff(Calo) = Events (Ecalo/E' > 0.7 & Cer >8) / Events (Cer > 8)

Improvement has been made, however at low E there still appears
  some loss of eff likely due to intrinsic ineff. of the calorimeter. 







Plots of event ID vs. calorimeter distribution (shower track) for each run
for old (top) and new(bottom) data.  Notice that the shifted blocks of data
have been aligned due to the new calibration.











Plot of Calorimeter Resolution fit to Gaussian



 

Tracking Efficiency

Eff(Tracking) = (TRG & PID & TR) / (TRG & PID)

where TRG: formed trigger, TR: found track, PID: particle id cut

Since the calibration there has been no improvement in the plot.  This could mean
calibration is not the issue. 






When plotted against W^2, we see that the inefficiencies occur in the resonance region
but as W^2 increases we obtain higher efficiencies.

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2) In Progress

-In the midst of doing a full replay of the calibration for all runs.
-Looking to obtain preliminary cross-sections.