[Lowq] Minutes of the eg6 Meeting on January 4

[Hovanes Egiyan]

  Minutes of the Meeting on January 4 at 9:30am


       From Lowqwiki

Present: F.-X., Carlos, Bayram, Hovanes.

On the phone: Lamiaa, Dave

Notes by Hovanes.


    Contents

[hide]

    * 1 IC calibrations
      <http://clasweb.jlab.org/rungroups/lowq/wiki/index.php/Minutes_of_the_Meeting_on_January_4_at_9:30am#IC_calibrations>
    * 2 DC calibrations
      <http://clasweb.jlab.org/rungroups/lowq/wiki/index.php/Minutes_of_the_Meeting_on_January_4_at_9:30am#DC_calibrations>
    * 3 Software status
      <http://clasweb.jlab.org/rungroups/lowq/wiki/index.php/Minutes_of_the_Meeting_on_January_4_at_9:30am#Software_status>
    * 4 EC fiducial cuts
      <http://clasweb.jlab.org/rungroups/lowq/wiki/index.php/Minutes_of_the_Meeting_on_January_4_at_9:30am#EC_fiducial_cuts>

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    IC calibrations

    F.-X. reported on the progress of IC energy calibrations

        * Invariant mass mean values from all channels are at ?=134.9
          MeV. The energy resolution is ?=9.6 MeV which is a little
          larger than from the previous IC experiments where ? was 7 or
          8 MeV. Might be to not optimal calibrations, some noisy
          channels, correction for vertex position, lower energy cutoff
          in photon selection (400 MeV instead of 800 MeV) to increase
          the statistics.
        * F.-X. did eight iterations, he showed plot of ?^0 mass versus
          iteration number with four sets of points. The red points are
          with simple parameterization by F.-X. for energy corrections,
          the blue points are with more complicated Rustam's
          parameterizations. The lower two sets of points are the mass
          of the ?^0 , the upper sets of points are mass of the ?^0 plus
          the resolution.
        * Resolution seems to have converge, no improvement is seen with
          iterations anymore.
        * Timing calibrations are still off, F.-X. may not have time to
          work on it. It would be good if someone could work on it.


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    DC calibrations

    Lamiaa reported on the activities related to DC calibrations.

        * Seema did another iteration for 1 GeV runs. She did not see
          overall improvement in the residuals, although some particular
          showed some improvements.
        * We are still using the old constants. We need to decide if we
          should go ahead with the old constants or wait for new ones
          from Seems for 6 GeV.


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    Software status

        * The software is pretty much ready for Pass1.
        * Lamiaa fixed some bugs which were causing seg. faults. These
          were related to array boundary crossing in ICHB and GCPB and
          were fixed by increasing the array sizes.
        * We will have ntuple, log-file, 2 ROOT files, helicity
          correction text file. We will have 1 single BOS file for both
          event types: negative TB track; and positive track with two
          neutrals.
        * F.-X. looked at the data event-by-event in the "h2root" ROOT
          file and noticed some duplicate events with identical event
          number in the HEAD bank. This need to be checked in other
          files as well. We need to keep this in mind if we do not fix
          this.


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    EC fiducial cuts

    Dave looked at U, V, W distributions of the hits in EC to determine
    the fiducial cuts on the face of EC.

        * Dave was taking the U, V, W values from the ntuple itself.
        * F.-X. suggested to calculate the U, V, W coordinates from the
          global X, Y, Z coordinates because one may miss some of U, V,
          W but still have all global coordinates. Stepan could clarify
          this issue. F.-X. will send a C++ routine to calculate U, V, W
          from X, Y, Z .
        * F-X also pointed out that at low values of U there can be
          "shadow" events from IC (junk from IC leaking into EC).

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