General Meeting Summary 9/28/16

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JLAB DETECTOR UPDATES (Arthur)

  • Bolts for wires are installed on SP-11 tray (safety feature for aerogel tiles once installed)
  • Preparations for aerogel tile installation ongoing, e.g., Aluminum cover to protect tiles from dust and mechanical damage when tray not in use
  • Action items:
  • SP-11 aerogel tiles to JLab (Friday 30 Sept)
  • Estimate density of materials for SP-11 tray - important for delta electron generation/contribution in experiments
  • Start NPS prototype tests of PMT shielding in magnetic field


DATA ANALYSES AND PROPOSALS

  • Discussion about new initiative: exploring potential for extracting pion form factor in medium using existing JLab 6 GeV data
  • Data from Fpi-1 experiment Q^2=0.6 GeV^2 setting - experimental yields from Aluminum target (used in experiment for background subtraction)
  • Main challenge is how to extract cross sections from these yields, background control
  • Theory background: see papers by J. deMelo - challenge is extrapolation to very small Q^2
  • Action Items:
  • Determine a method to extract cross sections from Fpi-1 yields (Al target)
  • Review theory and extrapolation
  • Determine pion statistics for CUA's kaon experiment (E12-09-011) Q^2~0.4 GeV^2 setting - experiment scheduled to run in 2017


  • Discussion about Timelike Compton Scattering (TCS) proposal (Arthur)
  • Action items:
  • Contact UVa theorist about general motivation and alignment with overall 3D hadron imaging program
  • Contact LANL theorist for feedback on impact of experimental projections (with current experimental configuration) on global fitting of Parton Distributions


  • Discussion about GluEx program and detectors (Greg)
  • Data analysis of 2015/16 data: many channels still available providing opportunities to get involved in the analysis process
  • Upgrade of GluEx - discussion of DIRC upgrade
  • Principle for compact detector: trap light in bar by total internal reflection, read signal out on side, away from interaction; typical number of photons is ~1000/particle, but lose many (inside bar, transition between media, detection efficiency) - SLAC Babar DIRC detected 20-60 photons/particle
  • Hall D/12 GeV project, set to start in 2017/18, current prototyping done at MIT
  • Initial design exists based on fDIRC SLAC design - working on simulations to optimize expansion volume
  • Re-uses components from SLAC BaBar DIRC and sensors from other detectors at JLab; DIRC bars need to be transported from SLAC to JLab - planning to build a laser system to check status of bars
  • Maintenance of CUA built tagger - need to figure out what is exactly involved in this


OTHER

  • APS April meeting abstracts
  • JLab activities Friday (30 Sept): 11:00am SAF801T (Andres, Rishabh, Rich) and SAF112 (Salina, TH); 1:30PM SAF801P, 3:00PM SAF110 - if time, check out the NPS prototype in EEL building
  • DVCS shifts
  • Printing APS DNP posters for summer students (Arthur and Greg will take care of this)
  • NPS and high intensity photon workshop organization/planning (summary below)


DISCUSSION ITEMS FOR NEXT MEETING

  • Update on crystal readout with semiconductor devices (Andres, Rich, Rishabh)
  • Update on JLab detectors (Arthur)
  • Data Analyses (Marco, Salina, TH, ...)
  • Kaon/pion form factor related
  • New initiative: pion/kaon structure functions and weak form factors)
  • DIRC tracking (Greg)
  • Other...


NEXT MEETING: WED. 5 OCT 2016, 10:00AM (EDT)


High Intensity Photon Sources Workshop Summary:

There has been recent discussion of a photon source with large gain in figure-of-merit to be used with both dynamically polarized targets to measure processes such as wide-angle and timelike Compton Scattering (WACS and TCS), and potentially to convert into a K_long beam for spectroscopy experiments. PAC43 and PAC44 at Jefferson Lab have seen a few proposals and several LOIs related to these photoproduction topics. The possible photon source would give a gain in figure-or-merit of a factor of 30 for some experiments. For processes such as wide-angle compton scattering and timelike compton scattering the high intensity photon source could be coupled with high-precision calorimetry. For the latter, plans are discussed in all four Halls. The workshop will take place at the Catholic University of America in January 2017, sufficiently early in time such that it will benefit proposals for PAC45.

The workshop will be dedicated at bringing together the communities using high precision calorimetry and high intensity photon sources, with the aim to consider the high-level science goals to be achieved by WACS and TCS processes, The workshop will also include discussions of converting a high intensity photon source into K_long beam. The emphasis will be on new avenues in hadron structure studies that could contribute to the existing program at JLab. By exploring new avenues for neutral kaon beams, it may also contribute to the hadron spectroscopy program. The workshop is aimed at producing an optimized photon source concept with potential increase of scientific output at JLab, and at refining the science for photoproduction experiments. The workshop will aid in addressing the PAC43 comments on a WACS proposal and LOIs on TCS and K_long beams, and also the recent PAC44 comments, and to prepare a full proposal for the next PAC.

Organizing Committee: Carlos Munoz-Camacho, Thia Keppel, Igor Strakovsky, TH

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