July 27, 2017 Calorimeter

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Meeting Time: 11:00 a.m.

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Participant Direct Lines

• JLab Phone in CC L207 is 757-269-7084 (usual room)
• JLab Phone: in CC F326 is 757-269-6460
• Phone in the Regina Video-conference Suite is 306-585-4204
• Athens Phone: in Christina's office is 011-30-210-727-6947

Action Items

1. Decide on procedure to calibrate 4ns offsets during the next run. Mark has written a plugin to obtain the 4 ns offsets in near-real time. Ready for Sean to test. For the Fcal, this calibration can be done after most other calibrations are complete.
2. Check in the code, including scripts, that is used for recent calibrations into git (BCAL: Mark, FCAL:Adesh)
3. Add Fcal dead channels into the MC

References

1. FCAL HDFCAL log book
2. BCAL HDBCAL log book

Tentative Agenda

1. Announcements
2. Action Items
3. Activities during the down
4. FCAL Update
5. BCAL update
6. Calibrations
7. Reconstruction and Simulation
   1. 2017 mcsmear Workplan
   2. BCAL charged clustering update (Will M.)
   3. Data and MC comparison for the f2(1270) -> pi0 pi0 decay (George V.)
8. NIM articles
9. Any other business

Minutes

Attendees: Ahmed, Zisis, Andrei, Tegan (UofR); Elton, Mark (JLab); Will, Curtis (CMU); Christina, George (Athens); Matt, Jon (IU)

1. Announcements
2. Action Items
   1. 4n offset calibration
      • Mark has written a BCAL plugin tracking pos vs time diff, which can be used to determine 4ns timing offsets. Code has been committed to sim-recon. Sean still needs to do some testing. This code can be used to determine 4 ns offsets as data are taken as long as reasonable tracking is available.
      • Fcal: 4 ns offsets do not directly affect low level calibrations, so they can be completed after routine calibrations. Checks of the 2017 spring data indicate that the shifts are valid for the whole run period. Adesh's procedure uses the LED skim data and comparison of individual runs compared to the entire period, so cannot be accomplished in real time in its present form.
   2. Scripts still need to be checked into git. It is on Mark's list
   3. Dead channels in FCAL.
      • Plan is to divide runs into groups of about 50 runs each. Use the LED runs to calculate a per channel efficiency to enter into ccdb. Need this before MC data sets are run so that the correct distribution of dead channels are populated in the MC.
3. Activities during the down
   • None.
4. FCAL Update
   1. Time-walk
      • Use LED data to look at time walk. Some progress, but find that the LEDs themselves show time shifts at different bias settings, which are larger than the time walk from the fADCs. Elton: with the fADCs the time walk should be small.
      • At the previous meeting summer student Rebecca Barsotti showed results of machine algorithms to separate photon from hadron showers. Feedback from the group suggested some improvements, in particular to not include the energy of the shower as an input variable. The programs were re-run and they find the performance is still very good. However, it is unclear where best to implement it, since it uses both very low level Fcal hits (not available in rest files) and also tracking information (produced during reconstruction). They are exploring options during the upcoming monitoring launch.
   2. Geometry of Fcal
      • There has been discussion regarding various aspects of the FCAL geometry, which are not yet implemented into our hdgeant model: A) light guide (David and his student Ebode have recently verified that a peak in the single-block spectrum of the Fcal is most likely due to Cherenkov radiation in the light-guide/cookie near the pmt) is not in the geometry description, but should be added to be able to better reproduce the energy lost by non-interacting hadrons in the FCAL. Richard will add the light-guide/cookie and track the energy loss in that volume separately from the lead glass. B) Block size in the model needs to be increased slightly to account for wrapping. The model still has the nominal bare block size of 4 cm. C) Add the light cover to the front of the FCAL (Elton).
5. BCAL update
   1. Simulation and Resolutions (Mark)
      • Comparing eta widths->gg for 2016 data to MC. Using ver5 trees for the reaction pi+pi-eta (gg)
      • Find that the data is broader than MC
      • MC is also broader and flatter than what is expected. Trying to understand the MC results and may wish to consult with Will.
6. Calibrations
7. Reconstruction and Simulation
   1. 2017 mcsmear Workplan
   2. Data and MC comparison for the f2(1270) -> pi0 pi0 decay (George V.)
      • Studying gp->f2 p, f2(1270)->pi0pi0. This is a step in the long term goal to study the eta_1 exotic decay to eta f2(1270).
      • Use genr8 MC, 9 GeV photons, with a t-slope of B=5 GeV-2
      • Christina: How to add baryons? Curtis: Could use bggen or combine baryon reactions from genr8 with the signal genr8 file. bggen has some baryon background channels, but not all.
      • George: How to use the AmpTools to fit the f0 + f2 waves? Matt: need to model neutral efficiencies in the MC. The amplitudes for the spin 0 and spin 2 components can be added without polarization. If polarization is included, then a model of the f2 polarization needs to be included. Curtis: Go into the rest frame of the f2 and plot the angular distribution of the pi0, that should provide information on the polarization of the f2. For a clean interpretation, the baryons need to be removed.
      • George: Plan to shift from genr8 to AmpTools, but need to write the amplitudes for this production and decay.
   3. BCAL charged clustering update (Will M.)
      • Study of matching charged tracks to clusters and changing the clusterizer to revisit these showers.
      • Various checks have been made, with MC muons, pions and omega channel with gp->omega p, omega->pi+pi-pi0.
      • New clusterizer is an improvement over default neutral clusterizer and is ready to be checked in.
      • Matt: Suggests that for the studies with omegas the CL cut be increased to something like 5% to obtain a very clean sample. This should reduced the amount of unused energy in the event.
8. NIM articles
9. Any other business