GlueX Offline Meeting, November 16, 2011

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GlueX Offline Software Meeting
Wednesday, November 16, 2011
1:30 pm EDT
JLab: CEBAF Center F326


  1. Announcements
  2. Review of minutes from the last meeting: all
  3. Reconstruction sub-group reports
    1. Calorimeters: Matt
    2. Tracking: Simon
      1. Kinematic_fitting_charged_particles_11/16/11: Will
    3. PID: DC dE/dx: Paul M.
  4. CCDB beta release report: Dmitry
  5. Action Item Review
  6. Review of recent repository activity: all

Communication Information

Video Conferencing


Talks can be deposited in the directory /group/halld/www/halldweb/html/talks/2011-4Q on the JLab CUE. This directory is accessible from the web at . You have to be a member of the "halld" Unix group to put files in the directory.



  • CMU: Will Levine, Paul Mattione, Curtis Meyer
  • FSU: Nathan Sparks
  • IU: Ryan Mitchell, Matt Shepherd
  • JLab: Mark Ito (chair), David Lawrence, Dmitry Romanov, Simon Taylor, Elliott Wolin

Reconstruction sub-group reports


Matt gave the report.

  • Will has checked in changes to BCAL code
  • When there is a demonstration of improvement with the new code versus the legacy KLOE code, the new code will be made the default.


Simon and Will gave reports.

Simon reminded us that problems have been reported with the proton reconstruction efficiency in b_{1}\pi events. A couple of rounds of improvements have been tried, with modest gains. Work on this continues.

In the light of recent improvements, Will has started looking at reconstruction efficiency and kinematic fitting for all-charged-final-state events. See his wiki page for details. He is seeing relatively high reconstruction efficiency, but not so good efficiency for passing a confidence level cut. Several people suggested restructuring the study to separate the effects of reconstruction and those of the calculation of errors.


Paul gave the report.

Paul has been doing studies of dE/dx in the tracking chambers. Recall that this component of particle identification has been dropped in the current version on the trunk. See his wiki page for details. He showed plots of dE/dx separately for the CDC and FDC, both means and sigma's for pions up to 9 GeV.

  • Matt pointed out that the action for us in the region below about 1 GeV where these quantities are varying rapidly. He suggested that Paul concentrate his efforts there.
  • There is a difference between the dE/dx in the CDC versus that in the FDC. Mark thought that it would be interesting to see if it could be accounted for by the different gas mixtures set in the Monte Carlo for the two systems.
  • Paul intends to run more statistics to fill out the variety of cases he has studied.

CCDB Beta Release Report

Dmitry released a beta version of the calibration and conditions database (CCDB) last week. In the subsequent testing, some surprises/anomalies in the use of the file-based calibration system were discovered. See his slides for details. The CCDB is a bit more formal than the file-based system, and there was consensus that adjustments to code and files will be done to make things more consistent.

Action Items

  1. Regularize the calibration files and related code to make them consistent with CCDB structure.