Difference between revisions of "BLTWG Meeting 4/24/2017"

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** phone: 408-740-7256 or 888-240-2560
 
** phone: 408-740-7256 or 888-240-2560
 
* Conference id: 536076821
 
* Conference id: 536076821
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* Present: <!--Richard J., Curtis M., Dan S., Alex B., Brendan P., Michael D., Justin S., Nathan S., Elton S., Alexandre D., Eugene C., Tim W., and Sascha S.-->
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* Present: Richard J., Curtis M., Dan S., Michael D., Justin S., Nathan S., Baalouch M., Alexandre D., Eugene C., Tim W., and Sascha S.
  
 
=== Agenda ===
 
=== Agenda ===
 
# Announcements
 
# Announcements
 
# [[GlueX-Collaboration-May-2017|Collaboration Meeting]] May 15-17, 2017 at Jefferson Lab.
 
# [[GlueX-Collaboration-May-2017|Collaboration Meeting]] May 15-17, 2017 at Jefferson Lab.
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# Progress with beam energy monitoring for spring 2017 run - ''Alexandre D.''
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# Update on beam energy scale calibration and matching - ''discussion''
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# Radiative corrections to the triplet asymmetry - ''discussion''
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# CB spectrum and polarization calculation - ''Richard J.''
 
# CB spectrum and polarization calculation - ''Richard J.''
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# Update on flux measurements
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# Update on instrumentation upgrades / improvements
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#* triplet polarimeter - ''Mike D.''
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#* tagger microscope - ''Richard J.''
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#* tagger hodoscope - ''Nathan S.''
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#* pair spectrometer - ''Sasha S''
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# Update on flux determination: proposed CCDB tables for each run [https://halldweb.jlab.org/wiki/index.php/File:TAGMtable.png TAGM] and [https://halldweb.jlab.org/wiki/index.php/File:TAGHtable.png TAGH]
 
# Update on calibrations
 
# Update on calibrations
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## [https://halldweb.jlab.org/doc-private/DocDB/ShowDocument?docid=3265 TAGM timing resolution and efficiency update] - Alex B.
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#* [[File:Plots.pdf]] Baalouch M.
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## [[File:Plots.pdf]] Baalouch M.
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# Update on simulations
 
# Update on simulations
 
# Any other business
 
# Any other business
  
 
=== Notes ===
 
=== Notes ===
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Response from A. Afanasev to question about the size of radiative corrections in the triplet process:
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* For next time: discuss ability to generate MC estimates of background radiation in the tagger hall and in Hall D
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I agree that 1.5% is getting close! For exclusive pion electroproduction (with a 3-body final state) we may have 25% overall correction factor, out of which 5% comes from a term proportional to cos(phi), i.e, azimuthally asymmetric; and 1% from cos(2phi).
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For Compton scattering - and your triplet process contains Compton amplitude - Thirring's low-energy theorem states that rad corrections to the cross section disappear in all orders of QED. We should see if sqrt(s) is small enough here to claim validity of the theorem. Chudakov, Ilyichev and myself calculated RC to Hall A Moller, and Konchatnyi&Korchin did RC for Ashot (Primex) for Compton scattering. I will check with Ashot on the outcome, but 1% was an accuracy goal for Primex.
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Latest revision as of 12:39, 24 April 2017

Organization

  • Time: 11:30 EDT
  • Connecting: detailed instructions are here
  • Conference id: 536076821
  • Present: Richard J., Curtis M., Dan S., Michael D., Justin S., Nathan S., Baalouch M., Alexandre D., Eugene C., Tim W., and Sascha S.

Agenda

  1. Announcements
  2. Collaboration Meeting May 15-17, 2017 at Jefferson Lab.
  3. Update on beam energy scale calibration and matching - discussion
  4. CB spectrum and polarization calculation - Richard J.
  5. Update on instrumentation upgrades / improvements
    • triplet polarimeter - Mike D.
    • tagger microscope - Richard J.
    • tagger hodoscope - Nathan S.
    • pair spectrometer - Sasha S
  6. Update on flux determination: proposed CCDB tables for each run TAGM and TAGH
  7. Update on calibrations
  8. Update on simulations
  9. Any other business

Notes

  • For next time: discuss ability to generate MC estimates of background radiation in the tagger hall and in Hall D
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