Minutes of the Blast analysis meeting on Wednesday 2006/04/19

From: Michael Kohl (kohlm@mit.edu)
Date: Wed Apr 19 2006 - 18:07:55 EDT


Hi,

here are the minutes of today's meeting

-Status calibration and recrunch (MK)
  +v3.4.18 complete for 2004 deuterium 7002-12143, new geom+field
  +now working on timing for 2004 hydrogen 12144-13278 and
   2005 deuterium 13279-16506

-Status spin angle (CC, CZ)
  +ed elastic: theta_e changed little, by ~0.1 degrees, acc. to Chi
   -> Take average of all measurements to define best profile
      (Doug will provide parametrization of the average of all maps)
   -> Shift this profile such that it becomes consistent with ed,ep
      (to be done by Chi and Chris)
   -> Use "corrected profile" in all analyses

-Mascarad issues (CC,VZ,CZ)
  +Goal was to use Mascarad to determine average momentum shifts due to
   Blast resolution convoluted with radiative yield
  +tml wrongly filled for radiated events?
   related to ntuple filling priority/lrn (fixed by CC)
  +Chi's concerned how appropriate the use of Mascarad is for kincorr.
   Issue of "realistic" resolution introduces uncertainty for the
   average shift of the radiated W, questioning strategy
  +Question is, by how much does the average momentum shift due to
   radiation convoluted with Blast resolution
  +CC's presentation
   -generates W-spectrum from data, corrected for total kinematic
    corrections
   -generates unradiated+radiated yield with Mascarad
   -convolutes Mascarad yield with a parametrized Blast resolution
    function, determines resolution parameters from fit to corrected data
   -Convoluting Mascarad-yield with resulting resolution function centered
    at proton mass results in a distribution that is shifted by ~1MeV. The
    resolution parameter sigma was ~24 MeV
   -> Concluding, there is no big radiative shift of the centroid!
  +CC is going to explain this more appropriately than I can, in a
   separate email.
  +three times more yield for "delta" in DGen compared to Mascarad fortran
   code
  +Reconstructed unradiated events (with cut on delta-peak) gives a
   distribution that is shifted by ~10 MeV. Using Adrian's MC file. Unclear
   to what extent old calibration/geometery may explain this. Differs from
   Eugene's findings back in March.

-Rehearsal talk on GEn at APS/Dallas (EG)
  +Dallas.ppt

  Best regards

    Michael

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