Dec 14, 2021 PrimEx-Eta (informal) Calibration & Analysis Meeting

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Time and Place

  • Time: Tuesday, Dec 14, 2021 at 10:30 am EST.
  • Room: Online

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  1. Announcements
  2. Status of Calibrations
  3. Calibration Updates:
    • Tagger (Tyler)
    • PS & Alignment (Sasha)
    • FCAL (ig)
    • CCAL (Drew)
  4. Analysis Updates:
    • Drew
    • Tyler
    • ig
  5. MC simulation Updates
    • Production (ig)


Present: Ilya, Tyler, Sasha, & ig

  1. Sasha was working in the hall
  2. Tyler reported the tagger calibration status. The calibration is done for each run, mostly automatically, but for some runs a fine-hand-tuning is needed.
  3. ig is learning how to use OSG to be able to launch the FCAL calibration. ig had some questions regarding the azimuthal angle difference between BCAL and SC. The expectation is that there should be a peak at zero degrees but the simulation (w/o magnetic field) shows a peak at ~ -45 degree. Ilya thinks that it is probably a bad alignment. ig will check the DB.
  4. Ilya explains the difference between eta & pi0 Primakoff cross-section calculation.
    • Form factor has a Real and Imaginary parts
    • eta has two form factors: Coulomb and Strong. The Strong FF can be tuned to the data by changing the nucleus radius.
    • pi0 has three form factors: one for Coulomb and two for Strong. The Strong FFs was tuned by changing the Silicon nucleus radius.
    • In both cases the interference has two terms cosinus phi (proportional to the Real part product) and sinus phi (proportional to Im part product). The phase angle is known for pi0 but not for eta.
    • For pi0, at small angle there is an integration problem that requires a parabolic approximation only for the Coulomb FF.