Agenda

Attendance

Arun, Hunter, Gordon, Andrew, Braian, David, Gary, Jack, Jacob, Jiwan, Saru, Sean, Todd, Vimukthi, Vladimir, Bogdan, Kate, Don

Jack's talk:

It makes sense that at higher Q2, the pion peak dominates
Better GEN4 BBCal calibrations will help clean up the peaks for this ps.e cut
Do we have a sense for how many good events we're losing by making the cut tighter around the electron peak?
- Electron energy doesn't vary all that much between kinematics, so the way the electron peak looks in GEN2 tells us what it'll look like in GEN4
- Efficiency of electrons for a 0.2GeV is pretty good.

Hunter's talk:

proposed 1-sigma cut on the mean of the peak for each window
- suggested absolute cut includes ~55cm of the 60cm target
entire peak should ideally be gone, so maybe a 3-sigma fit would be better
if you only look at quasi-elastics, you don't see these peaks:

use the real world knowledge of the width of the target windows to help understand the smearing
it might be good to use a window cut when we want to cut out background (get shape of background)
aside from Bogdan: data from optics target gives empirical information about N2?
this cut may not be needed in general if it is already taken care of by other cuts/calibrations
- later we can sanity check this cut value

Vimukthi's talk:

bb.gem.track.ntrack == 1
- this might be too tight
- look at first track regardless of number of tracks found so that we don't artificially lower efficiency
- "first track" is a complicated topic that would take a long time to explain, but it is directly related to the quality of the track (straight line through GEMs, hitting calorimeters, etc)
- change to bb.gem.track.ntrack >= 1 - Andrew
https://sbs.jlab.org/cgi-bin/DocDB/private/ShowDocument?docid=368 some documentation on GEM tracking

Gary's talk:

H2 events don't populate a certain area so it makes sense that if bbcal calibrations are only based on those then it makes sense that these areas aren't well calibrated
further bbcal calibrations using generic electrons instead of H2 data will help

Bogdan's talk:

assume you know helicity, what does this event tell you about it
- not quite a measurement of helicity
this is a slightly different method than original GEN formalism
this should lead to the same results
- experiment is stable with time (not helicity correlated beam corrections)
- charge asymmetry? amount of beam in helicty left = helicity right? Should be true
  - there are not totally trivial charge asymmetries that should be considered
A_i depends on Q2 and each event has a separate Q2
- GM and GE are kinematic dependent
event-by-event kinematic corrections is being done here
- dependence on Q2 is certainly not small
- great improvement to look at event-by-event instead of averaging over the entire experiment
should chi-squared minimize to 1? no
- how is this chi-squared metric consistent?
implement where the polarization of the beam is constant?
- steps in beam polarization add uncertainty

Think about Bogdan's method for discussion next week!

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