Agenda

Attendance

Arun, Kate, Jack, Braian, Vimukthi, Faraz, Sean, Gary, Andrew, Todd, David, Gordon, Hunter

Faraz's Talk:

beam polarization results are close to being finalized
systematic error has not been fully calculated
hall a statistical uncertainty is much smaller than that of hall b
- "Hall B has not put significant effort into understanding and correcting systematics in their Moller polarimeter (typically their physics doesn’t require high precision polarimetry)." - David
we don't have beam polarization data for the first two weeks of pass-2 beam.
- how do we account for this?
- hall c was also not in operation during this time
- it accounts for 4 days of GEn data taking
We might want to ask for expert opinions on the beam polarization's sensitivity to QE
square point on overall beam polarization plot still requires recalculations of AP so we cannot use its position to draw conclusions

Sean's talk:

Question based on slide 3: "This notation is a little confusing to me: in the parity experiments we separate out the intrinsic asymmetry from each source from the “dilution” from each source (the fraction of the events that arise from that background), so that the numerator would be of the form A_raw - f_p*A_pm - f_pi*A_pi…" - David
- f is the fraction of events coming from each source of asymmetries
- this notation comes from Seamus, but it may be better to use what other people use for asymmetries

how do we deal with N2?
- Estimated fraction of events from N2 that passed all the cuts was ~5% (lower Q^2) and ~7.5% (higher Q^2) in GEn-I, so we are dealing with a small number but not a negligible number.
- Andrew suggests estimating using Monte Carlo based on an estimate of N2 in the target compared to He3
- Gordon has good information on the amount of N2 in the targets for GEn-II. He has a spreadsheet with all the information on each target fill.
Should the background cut region used to get the background correction be much larger?
- the region to the right of the peak is lower velocity nucleons, so a cut on the left of the peak would be better to consider to avoid inelastics and other particles
  - it'd be even better to look at both sides of the peak
for pion correction, can we align everything with a single scale factor?
- we can use the grinch to help look at just pions
for the inelastic correction, can we measure the asymmetry in the inelastic region and extrapolate to the elastic region?
- Take asymmetry values and scale them
- statistical subtraction of the background for each helicity state so you get a "pure" neutron sample so that you don't even need to account for inelastics?
  - we can't do this in a run summation way, but we could do it with the total data
- unbinned maximum likelihood method?

See email invitation, or contact Arun Tadepalli for Zoom link.