Xiaochao Zheng reported on the status of the A1n analysis:
- The second round of analysis has been completed with beam tripsXiaochao reported the following issues:
and EPR measurements removed from the runs
- The detector calibration has been checked
- Target analysis: the average of the EPR and NMR measurements is
used to interpolate the polarization for each run
- Seonho has confirmed the preliminary result
- Acceptance cut and PID dependence studies underway
- Radiative corrections have been started
- There is
a 2sigma effect in both the acceptance and PID cuts, which could
be a statistical, systematic, or software problem
- For the
x = 0.61 kinematics, there is a difference in the first (pseudo-random)
and second (toggle) periods for the electron and pion asymmetries
- In ESPACE,
bad events were reconstructed back into acceptance
- For the
synchronization of event time and the scalar clock, ~ 15 runs are off
by 2 seconds in the last few days of the experiment. The change in
the DAQ
system needs to be understood for the two periods.
In the following months Xiaochao will work on:
- ESPACE check
- Continue
cut dependence studies
- Radiative
corrections
Xiaochao's long-range plans are
Target Analysis,
BPM and raster corrections, Analysis on nuclear effects,
cross section
study, and extact g1 and g2.
Nilanga Liyanage reported on the A1n analysis:
- For ESPACE,
CWN ready for both experiments, problems fixed,
and Beta and ev_time were added to the ntuples
- Nilanga
optimized: Beta for 2 periods of A1n, the spectrometer detector offsets,
the VDC and scintillators
- The absolute
momentum is good to < 5 x 10^-4
- Presently
optics for the cross sections is being improved (Al Nathan's student)
Seonho checked Xiaochao's results:
- Seonho used the same runs as Xiaochao with the following results:
- For radiative corrections, Seonho said we lacked information
in the resonance
region at low Q^2. He also looked
at various radiative corrections to the data