[Clas_hadron] HSWG CLAS12 meeting on Tuesday September 11 at 11:00AM (EDT) - SPECIAL MEETING -

Tue Sep 11 10:40:09 EDT 2018

Dear all,
tomorrow I won’t be able to participate - I’m flying back from JLab. I’d like to give you an update on the status of the trigger validation preparation.

All the trigger files are ready 
I had the chance to go through the analysis code and clean it up, so now it is much faster and (hopefully) also readable by other collaborators who want to help in this effort
The analysis also include the evaluation of the Forward Tagger trigger efficiency - the data to perform this studies can be the same as the data collected (with random trigger) to evaluate electron trigger efficiency in CLAS12 (can’t be the data we’ll use to evaluate MesonEx trigger due to the bias we have in the trigger file for these studies).
The analysis code for the moment doesn’t include central detector trigger efficiency evaluation, and I don’t think there were much progresses on that from the hardware point of view.
As part of this effort, I re-run the code on run 4288 (random trigger we took last spring). These are my findings concerning the FT:
The clustering efficiency is about 99.6%. This means that, for reconstructed clusters, 99.6% of the time there is also a cluster seen by the VTP trigger board, in the same position. See attached plot #1, black is the energy of all reconstructed clusters, red is the energy of reconstructed clusters that have a match in the VTP.
For those few events not matched, I see that there are many VTP clusters, close to the reconstructed one (in terms of crystals X and Y). I think what is happening here is due to the 3x3 limitation in clustering regions in the VTP, not present in the reconstruction. If this is the case, the trigger will still fire for these events, although the reported energy may be smaller than what found in the reconstruction.
The “charged-cluster” efficiency is about 95%. This means that, for reconstructed clusters that have a matching hit in both hodo layers, 95% of the times there si also a charged cluster seen by the VTP trigger (again, “charged” means that the VTP matches this with one hit in each of the two hodoscope layers). See attached plot #2, black is the energy of all charged reconstructed clusters, green is the energy of charged reconstructed clusters that have a charged match in the VTP. There may be different reasons for this inefficiency.
I excluded it is a threshold effect - the inefficiency is almost the same, no matter of the energy deposited in the hodoscope layers 
I excluded it is a timing effect - the inefficiency is almost the same, no matter of the time difference between calorimeter cluster and hodoscope hits (checked all combinations)
It may be that, in the reconstruction, we have a large geometrical tolerance when doing the match between calorimeter and hodoscope - this is also related to the fact the VTP just considers 3x3 regions for clustering. In order to verify this, I’ll need to scrutinize some events with a charged reconstructed clusters, not matched to the VTP, also making use of my the trigger simulation code. If this is the case, it is not really an inefficiency, just a different algorithm to identify charged clusters by matching with the hodoscope.
It still may be some “fancy” timing issue with the VTP - again, I’ll need to run my trigger simulation code to verify this.
The plan is to try to find an answer before we’ll run again, in order to make sure that any possible configuration change is implemented from day 0.
Bests,
Andrea

> On Sep 10, 2018, at 13:24, Marco Battaglieri <battaglieri at ge.infn.it> wrote:
> 
> Dear all,
> we'll have our meeting tomorrow Tuesday September 11 at 11:00 EDT
> 
> The meeting is (almost) entirely devoted to review the status of the CLAS12-related analyses granted with a presentation at DNP this fall.
> The agenda is posted here:
> https://www.jlab.org/Hall-B/secure/hadron/wiki/index.php/Tuesday_September_11%2C_2018 <https://www.jlab.org/Hall-B/secure/hadron/wiki/index.php/Tuesday_September_11%2C_2018>
> All HSWG is strongly encouraged to attend!
> 
> For speakers: 
> This is the good time to check results form  freshly cooked data, discuss possible problems and issues to be solved in a time-frame of about a month (before the actual date of the meeting).
> Please make good use of this occasion presenting a critical review of your analyses. Analysis and software experts attending the meeting are eager to provide any necessary support and help to obtain the best from CAS12! Please, try to stay in 10mn each  to have enough time for discussion.
> 
> For people on-site we reserved  room F3424
> For people off-site here is the link to the BJ meeting
> https://bluejeans.com/928575007 <https://urldefense.proofpoint.com/v2/url?u=https-3A__bluejeans.com_928575007&d=DwMDaQ&c=lz9TcOasaINaaC3U7FbMev2lsutwpI4--09aP8Lu18s&r=qGyl0IJr8AB0_IWqnrWZ9cIvl3oTYfMtz1Flwf5x2uA&m=Gp-MjJKxFJBfnPOZQSjiTBqyIB7bWQUiil9RUtFXCWw&s=_e7uho1SZUNDYhGrLQjzxO4x4ljYUbertDu6JuB1BQw&e=>
> Cheers
> Marco
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