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

[Valery Kubarovsky]

Dear Silvia,
You have to take into consideration that rgc group is using very weak electron trigger.
We don't use DC roads or Q2 trigger up to now by unknown for me reason.
Most of the events have nothing to do with the electron in the final state, it is just garbage.
You will find electron (PID=11) only in 15% of the events.
I want to say that the purity of the rgc trigger is 15% only like in old CLAS experiments.
Do you have somebody who is analyzing rgc data today?
Best regards,
Valery

________________________________
From: Rgc <rgc-bounces at jlab.org> on behalf of silvia at jlab.org <silvia at jlab.org>
Sent: Tuesday, August 16, 2022 10:14
To: rgc at jlab.org <rgc at jlab.org>
Subject: [Rgc] status of the RGC data taking and nDVCS perspective

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


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