Star-tpc-l mailing list

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

Hi, TPC-ers

I decided to give a try at finding h-/h+ in the Run 22 pp500 data with the 
new TPC alignment and prior (older) TPC alignment to see what differences 
there are in sector-to-sector variations, perhaps also to inform the 
alignment choice for the production of Run 22 data. The 19.6 GeV data did not 
show improvements in the scale of those variations, and I was expecting that 
the pp500 data would be similarly insightful....but unfortunately to no 
avail. It appears that with my track selection criteria, I'm unable to 
sufficiently measure sector-to-sector variations at high pT in the pp500 
data. I suspect the issue is dominance of pile-up track contamination, but I 
haven't fully convinced myself of that. Low pT sector differences are quite 
clearly tied to outages in the individual sectors.

I've recorded my results here:

https://drupal.star.bnl.gov/STAR/blog/genevb/h-h-Run-22-pp500-new-TPC-alignment

Thanks,
-Gene

> On Nov 22, 2024, at 12:32 AM, Van Buren, Gene <gene AT bnl.gov> wrote:
> 
> Hi, TPC-ers
> 
> This evening I took advantage of the calibration production of the 19.6 GeV 
> AuAu 2019 data with the new TPC alignment to look at h-/h+ ratios. I also 
> looked at h-/h+ for this same dataset back in 2021 using the P21ia 
> calibration production with an older version of TPC alignment, allowing for 
> a direct comparison of whether the new alignment improves the 
> sector-to-sector variations that have been seen in past TPC alignment 
> versions. Unfortunately, while this analysis shows that the new alignment 
> has changed most sectors' distortion of h-/h+, its sector-to-sector 
> variations remain at a similar scale.
> 
> https://drupal.star.bnl.gov/STAR/blog/genevb/h-h-Run-19-196-GeV-new-TPC-alignment
> 
> Caveat: since the h-/h+ ratios I show are normalized to the integrated 
> ratio, this analysis does not demonstrate whether the new alignment 
> improves (or not) any overall biases (it may in fact do that). It is useful 
> only in the sense of looking at variation between the sectors.
> 
> Thanks,
> -Gene