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2025 Cosmics, momentum resolution, RF and FF.

Updated on Mon, 2025-03-31 10:41. Originally created by fisyak on 2025-03-31 10:41.

 So far it has been taken 168.83 M Cosmic triggers with Reverse Full Field.
This data has been processed. So far we have  56.681M event with >= 2 reconstructed tracks.

In 2024 we have 24.227 M events with FF and 41.378 M event with RF (https://drupal.star.bnl.gov/STAR/system/files/Tpc%20Alignment%202024%20overview.pdf).
In 2024 the momentum resolution at pT = 1 GeV/c was 1.5%.  
The data processed for 2025 with aligmnet from 2024   (https://www.star.bnl.gov/~fisyak/star/Tpc/Alignment/Cosmics2025/c1.html) shows the resolution 1.72%, i.e. 2025 data shows degradation ~20%.
Thus it will be necessary to do alignment for 2025 to recover these 20%. Usually we do alignment for both magnetic field directions:


  • to understand that TPC is (NOT ?) moving with the flip of magnetic field direction.
  • try to split geometrical and ExB static distortions.

We have  recorded cosmic trigger rate ~10M/day. To have comparable statistics for RF and FF we all need ~10 days. 

 
#Delta 1/p_{T} from cosmics muons

#Delta 1/p_{T} from cosmics muons

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