STAR QA Board

[Benjamin Kimelman <bkimelman@ucdavis.edu>]

Hello All,

After the QA Board meeting today, I dug further into this issue with primary tracks in these nine runs of the 3.85GeV FXT data. I have updated the presentation on the meeting page with the findings, and you can also find it here: https://drupal.star.bnl.gov/STAR/system/files/3p85_GeV_FXT_2021_Number_of_Primary_Tracks.pdf

The main conclusion is that this is a problem with the nHitsDedx distributions for these runs. Compared to a normal run, there are more than x10 more primary tracks with nHitsDedx=0. This does not appear to depend on the time in the run, nor do I see it depending on when the picoDSTs were written to disk (though it's possible that it depends on when the jobs were submitted, but I don't know how to check that).

There was a suggestion to look at the MuDSTs, which I have not yet done. My thinking is that we have properly identified tracks that have the right nHitsFit and trace back to the primary vertex, but somehow there is a problem with the dE/dx hits, and this shouldn't be any different between the MuDSTs and picoDSTs, since that value is just passed along in StPicoDstMaker.

I have added a number of plots which show that this is an issue with the number of primary tracks, but I do not know what to do about it. Does anybody have any ideas as to what we can do to identify why we have this problem with nHitsDedx in these nine runs but not others?

Best,

Ben Kimelman

Ph.D. Candidate, Nuclear Physics Group

UC Davis

He/him/his

On Fri, May 14, 2021 at 11:11 AM William Llope via STAR-QAboard-l <star-qaboard-l@lists.bnl.gov> wrote:

Hi frank and all,
at the meeting today Lanny reported on dE/dx shifts in specific runs:
        22127018, 22130029, 22131019-22, 22131043               

Maybe just a coincidence, but I note that several of these runs
(22127018, 22130029, & 22131022) were the last run in a fill.
cheers
     bill

> On May 13, 2021, at 11:13 PM, Frank Geurts via STAR-QAboard-l <star-qaboard-l@lists.bnl.gov> wrote:
>
> [EXTERNAL]
>
> Hi,
> We will have our Run21 QA meeting tomorrow (Friday) at noon (EST).
>
> Meeting details, including the Zoom link can be found at the following event link:
>  https://drupal.star.bnl.gov/STAR/event/2021/05/14/run-21-qa-board-meeting
>
>
> Best,
>
> -Frank
>
>
>
> Topic: STAR QA Board
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> ______________________________________________________
> Frank Geurts   (he/him/his)
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> T.W. Bonner Nucl. Lab. • Dept. of Physics & Astronomy
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