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["Van Buren, Gene" <gene AT bnl.gov>]

Hi, all

If anyone can correct the following statements, here's what my current 
understanding of the FXT T0 situations is....

1) There is no presentation/evidence that the FXT T0s are problematic for 
analyses in real data reconstruction, but there is an observed tracking 
inefficiency in embedding reconstruction.

2) The existing event-by-event FXT T0 corrections used in FXT may be 
incorrect for of order(20%) of the events, which we could improve if there is 
an expressed need (one dataset has already been re-calibrated by me: 2019 
3.85 GeV, but the others have not).

If no one disagrees with these two statements, then I think we need to give 
the green light to the FXT re-production that was requested for the purposes 
of improving dE/dx (Yuri noted this was ready a few weeks ago). I believe 
that Tommy is looking into simulations with Yuri's help to see if the 
east-west reconstructed vertex z difference can be better understood, but I 
don't know why that study would impact the real data reconstruction jobs.

Thanks,
-Gene




> On Jul 21, 2023, at 4:39 PM, Van Buren, Gene via Star-tpc-l 
> <star-tpc-l AT lists.bnl.gov> wrote:
> 
> Hi,
> 
> I said I'd try to find the presentation from the recent Analysis Meeting 
> where the concerns were raised about track-splitting at the central 
> membrane in FXT data. I did not attend the meeting, so it's been a hunt for 
> me. All I could find was...
> 
> 1) Slide 14 of Yuanjing Ji's talk (LBNL):
> https://drupal.star.bnl.gov/STAR/meetings/STAR-Analysys-meeting-and-BES-II-workshop-towards-QM23/BES-II-workshop-LFSUPC-and-Centra-10
> However, just looking at the slides, it looks like an inefficiency reported 
> in the embedding, not the real data. The topic I've heard discussed at the 
> TPC meetings started with a proposal to further smear the simulation to 
> match the real data, but if the simulation shows less efficiency than real 
> data, then we're on the wrong track. So I assume I misunderstand something 
> here. Does someone know the details better?
> 
> 2) Slide 13 of Yingjie Zhou's talk (CCNU):
> https://drupal.star.bnl.gov/STAR/meetings/STAR-Analysys-meeting-and-BES-II-workshop-towards-QM23/BES-II-workshop-LFSUPC-and-Central-9
> ...which simply refers to Yuanjing Ji's talk.
> 
> There are two UCDavis talks on FXT data near the very end of the Analysis 
> Meeting, but I didn't see any mention of reconstruction issues in either of 
> them.
> 
> Thanks,
> -Gene
> 
> 
>> On Jul 20, 2023, at 12:38 PM, Richard Witt via Star-tpc-l 
>> <star-tpc-l AT lists.bnl.gov> wrote:
>> 
>> 
>> Present: Alexei, Flemming, Tommy, Yuri, Gene, Jim, and myself
>> 
>> == Hardware
>>      — nothing new to report today
>>      — only concern is about methane delivery 
>>              — have about 30 days
>>      
>> 
>> == Electronics
>>      — system continues to perform well
>>      — test was done with TPC at 70 kHz (ZDC rate) for rare trigger program
>>              — performed well
>>              — no more problems than usual
>> 
>>                      
>> == Software
>>      — dAu and AuAu 17.3 SC calibrations are done (Run 21)
>>              — 17.3 calibrations took only a day
>>              — all information has been uploaded to dB
>>      — large calibration productions have been produced from each of those 
>> datasets
>>              — TPC dE/dx can now go forward
>>      — no activity in SC from Run 22 and 23
>>      — high luminosity coming, should check for GG leak since have best 
>> sensitivity there
>>              — will be looking for changes to distortions due to different 
>> GG rate
>>      — Event-by-event T0 in FXT data
>>              — PWG has seen track breaking across central membrane in FXT 
>> data
>>              — concern that may be T0 (but have not ruled out drift 
>> velocity)
>>              — Gene looked at prompt hits (sent findings to list yesterday)
>>              — only ~20% of events Irakli looked at may have issues (due 
>> to side of EPD used or 0 timing from chosen side)
>>              — actual impact on dataset from that 20% is not easy to see
>>              — Tommy suggested using simulations to determine expected 
>> effect
>>              — Gene asked for a link to the presentation that originally 
>> reported the issue but we do not know which one
>>      — dE/dx for FXT in Runs 19 and 20 is done and entered in dB
>> 
>> 
>> == AOB
>>      — Richard is being added as a reviewer for TPC code
>> 
>> 
>> Best Regards,
>>  Richard
>> 
>> Sent from my iPad
>> -- 
>> "Education is the most powerful weapon which you can use to change
>> the world."
>> 
>> --Nelson Mandela
>> 
>> ~~~***~~~***~~~***~~~***~~~***~~~***~~~***~~~***~~~***~~~***~~~***~
>> Richard Witt, Professor of Physics     Phone (USNA): 410-293-6675
>>    United States Naval Academy         Email: witt AT usna.edu
>> ~~~***~~~***~~~***~~~***~~~***~~~***~~~***~~~***~~~***~~~***~~~***~
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