01/29/2004

Target lab:

• Lingyan:

     - One laser looks weaker than the others for the same power setting.
     - Jian-Ping suggested to clean the fibers and measure the power of each laser..

Small angle GDH:

• Tim:

     - Showed trigger, charge and physics asymmetries for several runs on the left arm.
     - The charge asymmetry is sometimes large: more than 1000ppm


• Vince:

     - Optics optimization:
         * still some distortions appear: phi_tg not good.
         * y_tg looks good.
         * down stream reconstruction looks better.
         * 2 of the 4 runs used for the optimization had raster on: it can be one source of the optimization imperfections.
     - Water calibration:
         * The deformed background might not be due to the use of the A-phi box but from the subtraction of the slope in the raw signal.

Spin duality analysis:

• Patricia:

     - Showed trigger efficiency but a cut is missing on ntrack=1 in the trigger efficiency analysis.
     - Showed VDC efficiency for each kinematic with different cuts. Jian-Ping suggested to extract the VDC efficiency for electons selected by the PID analysis.
     - Then will have to do the parallel analysis for pions.
     - Jian-Ping adviced to extract the efficiencies for all runs (not only for each kinematic).

01/22/2004

Target lab:

• Jian-Ping:

     - Lingyan Zhu is starting to work on the target in preparation for Transversity.
     - The plan is: alignment of the optics, spin up, temperature test and other tests, and then get EPR working.

Small angle GDH:

• Tim:

     - looked at the helicity scaler analysis for the left arm.
     - saw the 4-peaks structure in the charge asymmetries


• Vince:

     - Optics optimization:
         * some holes disappear after cutting on elastic peak --> these events lost energy going through the pick-up coils.
         * reconstruction of the y_tg peak looks pretty good already.
     - Water calibration:
         * Used Karl's suggestion of taking the standard deviation of individual sweep to get an error on each point.
         * Up sweep with A-Phi box doesn't have the distorded background of the down sweep.
         * Need test and study of the A-Phi box in the target lab.

Spin duality analysis:

• Patricia:

     - Looked at the VDC and trigger efficiencies but didn't applied the proper cuts. So have to do it again.
     - Started to work on the elastic analysis: comparison of the target variables with the simulation without applying any cut on the data.

01/08/2004

Target lab:

• Kathy:

     - Target lab status is behind schedule.
     - Some problem with the oven controller and air flow that need to be optimized.
     - Need more work on the laser alignment.
     - The plan is to set up everything then to make EPR work and to do all regular polarization tests.

Small angle GDH:

• Nilanga:

     - Went back to the matrix elements from John Lerose because only three foils were used during the experiment.
     - After optimization, a shoulder appears adjacent to the upstream foil --> probably from the Be window.
     - The idea is to apply a cut to remove the Be window during the optimization.


• Vince:

     - Water calibration: looked at the CHI² evolution with interval fitted.


• Tim:

     - Worked on the Compton analysis.


• Alexandre:

     - Worked on the background study: he is looking at the internal radiative correction in glass.

Spin duality analysis:

• Patricia:

     - Used an older version of ESPACE from Seonho than the one used in her analysis so far.
     - Now all elastic runs can be replayed.
     - But still several runs show a number of events equal to -1 at other energies.

GDH:

• Karl:

     - Worked on the interpolation.
     - Need to implement the new elastic tail data generated by Alexandre.