sPHENIX HCal discussion

[Stefan Bathe <stefan.bathe AT baruch.cuny.edu>]

Dear All,

Here the minutes of today’s meeting (also on indico).

Regards,

Stefan

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Dan Lis—simulation update (see slides)

—————————————————————————————————

- Energy-angular distribution

  - distribution based on decay length of muon

  - still has to fix infinity from 1/tan

  - subscript d denotes decay; d denotes height of absorber (atmosphere)

- full detector response in phi and single sector

  - slide 4:

    - response smeared out for upper and lower sectors

       - presumably b/c of hits in parallel of tiles/absorbers vastly varying the path length for energy deposition in active material case by case

      - could test by studying different cases (ACTION ITEM)

   - energy distribution shifted to lower energy in lower tower compared to upper tower

     - presumably due to muon energy loss in upper tower

     - could test by studying response for different muon energies (ACTION ITME)

  - slide 5:

    - 3 tower cut cleans up E distribution

    - why still so much wider for towers not in horizontal position?

- next:  finish single sector simulation

Saif—pre-production re-calibration (see slides)

———————————————————————————————

- re-calibration of pre-production PR values confirmed

- Saif will produce prioritized list of towers where PR range has become large as a result of the re-calibration (ACTION ITEM)

- Hanpu will study corrected MPV distribution for those towers, and for the the others (ACTION ITEM)

- we will investigate how much effort it would be to change some tiles (accessibility; availability of spares)

Hanpu—fitting of MPV distribution

———————————————————————

- reminder:  from Shuhang’s analysis of 3-“tower” cut looks like background can also be described by Gamma distribution

- tried Gamma+Gamma fit

- often does not work so well (reaches parameter limits; large xhi^2)

- Gamma + pol1:  xhi^2/ndf = 1

- Gamma alone:                      1.2; not many outliers

- Gamma + Gamma:              > 1, many outliers

- Delta (fit - peak find) < 0 for Gamma; > 0 for Gamma+pol1

  - systematic difference between the two fits is 2.6 %

  - < 0 qualitatively explained by bias from peak finder (peak finder uses symmetric Gaussian while distribution is asymmetric Landau); but Shuhang doesn’t expect bias to be this large

  - Stefan 

    - trusts Gamma alone more than more complicated Gamma + linear

    - is concerned about unknown tower-by-tower bias in the latter

    - is not surprised that Gamma+pol1 has better xhi^2 since it has more parameters

  - Hanpu will try Gamma+pol1 over full peak range (so far restricted to peak region) (ACTION ITEM)  

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Stefan Bathe

Professor of Physics
Baruch College, CUNY

Baruch:                                     BNL:
17 Lexington Ave                      Bldg. 510
office 940                                  office 2-229
phone 646-660-6272                phone 631-344-8490
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On Aug 24, 2021, at 10:06 AM, Stefan Bathe <stefan.bathe AT baruch.cuny.edu> wrote:

Dear All,

Just a reminder that we’ll have our regular HCal muon calibration meeting at 11:00am today:

https://indico.bnl.gov/event/12852/

(Zoom info below)

Regards,

Stefan

ZOOM INFO:

Stefan Bathe is inviting you to a scheduled Zoom meeting.

Topic: HCal Calibration
Time: This is a recurring meeting Meet anytime

Join Zoom Meeting
https://baruch.zoom.us/j/81749330526

Meeting ID: 817 4933 0526
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---------------------------------------------------------------------------------
Stefan Bathe

Professor of Physics
Baruch College, CUNY

Baruch:                                     BNL:
17 Lexington Ave                      Bldg. 510
office 940                                  office 2-229
phone 646-660-6272                phone 631-344-8490
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