View source for GEn Analysis Meeting March 21 2024 10AM EST

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=Agenda=
# Preshower energy cut-> Jack Jackson [[File:Bb.ps.e cut.pdf]]
# Target vertex cut -> Hunter Presley [[File:Target Vertex Cut (1).pdf]]
# Number of hits per track cut -> Vimukthi Haththothuwa Gamage [[File:Bb.gem.track.nhits.pdf]]
# BBCal energy cuts -> Gary Penman [https://sbs.jlab.org/cgi-bin/DocDB/private/ShowDocument?docid=546]
# Proposed GEN asymmetry analysis procedure -> Bogdan Wojtsekhowski [https://sbs.jlab.org/cgi-bin/DocDB/private/ShowDocument?docid=548]

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

=Minutes=
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:
[[File:Screen Shot 2024-03-21 at 10.23.23 AM.png]]
* 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!

=Meeting link information=

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