[Rgc] status of the RGC data taking and nDVCS perspective

[silvia at jlab.org]

Dear all,
I just ran my script to check the status of the data taking.
Here is where we stand for 10.5-GeV, FT ON:

total events 12126288227
total nh3 4172837461
total nd3 6075008990
total carbon 1321716288

total nh3+ 2297297723
total nh3- 1875539738
total nd3+ 3085305030
total nd3- 2989703960

total nh3+ hwp in 1032553282
total nh3+ hwp out 1264744441
total nh3- hwp in 856758263
total nh3- hwp out 1018781475
total nd3+ hwp in 1454208809
total nd3+ hwp out 1631096221
total nd3- hwp in 1651649502
total nd3- hwp out 1338054458

Following yesterday's discussion, I started a rough comparison, by looking
back at the total number of collected triggers for RGB. Considering the
datasets we used for nDVCS (Spring19 and Spring20), we had a total of
~34.3B triggers, all with FT ON. From these data we obtained roughly 140k
nDVCS events. ~70% of these events have a photon in the FT. Given the
small size of the nDVCS BSA (~5%), we managed to get only 2D beam-spin
asymmetries (vs phi and one variable at a time between Q2, xB, t).

Right now in RGC we have ~6B ND3 triggers. The dilution factor for nDVCS
is expected to be around 40%, from Noémie's simulations. Assuming same
acceptance/efficiency as RGB, this yields about 10k nDVCS events collected
until now in RGC, a factor of ~14 less than RGB. The nDVCS TSA is expected
(VGG predictions) to be about a factor of 3 bigger than the nDVCS BSA,
which roughly compensates the ND3 target polarization (which seems, from
preliminary PbPt analysis, around 30%).

I will look into pDVCS in the next days, unless anyone else wants to do it.

Best regards,
Silvia