Minutes of the Blast analysis meeting on Wednesday 8/16/2006

From: Michael Kohl (kohlm@mit.edu)
Date: Fri Aug 18 2006 - 09:09:39 EDT


Hi,

below are the minutes of last Wednesday's analysis meeting.
There is a new directory on the Blast website where paper drafts are collected:
http://blast.lns.mit.edu/PRIVATE_RESULTS/DRAFTS/

Minutes:

-Discussed status of the GEp/GMp paper.
  +As of Friday 8/18, a new text version was created, yet it circulates
   between MK,HG,JC,DH,CC,AS. Figures still need to be updated.
  +Issue of what exactly is plotted as "world data" for GE and GM.
   Recommendation is to plot GE and GM from published Rosenbluth data as
   is. Need to identify those data.
  +Issue how to exactly combine BLAST ffr with world cross section.
   Recommendation is to utilize Arrington's parameterized extraction of
   GE and GM from Rosenbluth data <1 GeV to correctly evaluate the cross
   section at the kinematics of each Blast Q2 bin (acc. to Arrington's
   PRC69 the cross sections are know to better than 2%.) With Arrington's
   complete covariance matrix from his fit an appropriate error can be
   assigned to the cross section. Subsequent separation of GE and GM with
   the ratio including error propagation is then straightforward and does
   not require any fitting of other data.
  +HG at LNS today (Friday), plan is to settle these issues and to finalize
   the draft next week.

-Status timing calib/recrunch
  +See ppt
  +Summarizing presentation of what Mark has done
  +Static timing calib sufficient for proton/deuteron separation (ed
   elastic - T_qk), but not for neutral tracking (e,e'n - GEn)
  +Resolved pending issues with previous run-by-run calibration / gaps,
   jumps, sidebands
  +Mark has updated the entire mysql database for the 2004+2005 time calib,
   with significant changes compared to the previous version
  +Mark redid time calibrations for both 2004+2005:
   -Stabilized peak finding for flasher signals in TDCs (this had caused
    noisy peak location and "sidebands")
   -Interpolation of periods with missing flasher
   -Discontinuities: Sometimes real, sometimes fake, spent quite some
    effort to understand this
   -Evaluated as many cosmics runs as possible to "calibrate" the flasher
    monitor
   -(All?) remaining discontinuities in the final offsets are correlated
    with documented "events" in the elog such as Fastbus reboot, HV power
    cycling, trigger download etc., i.e. this is exactly the purpose of the
    monitoring to cover this.
  +2005 deuterium recrunch (v3_4_21) 75% complete
  +As of Thursday 8/17, 2004 hydrogen v3_4_21 recrunch complete
  +Quality is being evaluated after recrunch by looking at
   pathlength-corrected time correlation of coincidence events (e,e'n),
   (e,e'gamma), (e,e'p), all as function of run number and broken down
   into detector channels.
   So far with a limited range of runs, it looks very good. Some
   questionable periods need to be evaluated when results are available
   If quality still not good enough when utilizing the flasher monitor, we
   may revert to pure cosmics calib of offsets and some interpolation
   between cosmics runs. But this may be the case only for a few detector
   channels if at all.

  +Will continue to crunch with lrd/v3_4_21 for 2005 deuterium and then
   also for 2004 deuterium, expect completion in ~2-3 weeks; quality
   evaluation is awaited.

Regards,

    Michael

+-------------------------------------+--------------------------+
| Office: | Home: |
|-------------------------------------|--------------------------|
| Dr. Michael Kohl | Michael Kohl |
| Laboratory for Nuclear Science | 5 Ibbetson Street |
| MIT-Bates Linear Accelerator Center | Somerville, MA 02143 |
| Middleton, MA 01949 | U.S.A. |
| U.S.A. | |
| - - - - - - - - - - - - | - - - - - - - - -|
| Email: kohlm@mit.edu | K.Michael.Kohl@gmx.de |
| Work: +1-617-253-9207 | Home: +1-617-629-3147 |
| Fax: +1-617-253-9599 | Mobile: +1-978-580-4190 |
| http://blast.lns.mit.edu | |
+-------------------------------------+--------------------------+

---------- Forwarded message ----------
Date: Fri, 7 Jul 2006 11:57:49 -0400 (EDT)
From: Michael Kohl <kohlm@mit.edu>
To: "[BLAST_ANAWARE]" <Blast_anaware@rocko.lns.mit.edu>
Subject: Special Blast analysis meeting on Wednesday 7/12/2006

Hi,

though I had announced earlier to cancel next week's meeting, we decided to
still have one on Wednesday 7/12/2006 at !! 10:00 !! at Bates.
Note that 10am was chosen as there is a STAR collaboration meeting ongoing at
MIT with a session on spin physics in the afternoon.

By the time Sasha Ilyichev will be at Bates. The meeting will be about
radiative corrections at Blast:

-Summarize status quo of treating radiative effects in Blast
-Define task list, priorities, estimate of effort

Sasha will also give us a presentation on details of the procedure of handling
radiative effects in elastic and inelastic scattering at the collaboration
meeting on Friday 7/14.

Best regards

   Michael

+-------------------------------------+--------------------------+
| Office: | Home: |
|-------------------------------------|--------------------------|
| Dr. Michael Kohl | Michael Kohl |
| Laboratory for Nuclear Science | 5 Ibbetson Street |
| MIT-Bates Linear Accelerator Center | Somerville, MA 02143 |
| Middleton, MA 01949 | U.S.A. |
| U.S.A. | |
| - - - - - - - - - - - - | - - - - - - - - -|
| Email: kohlm@mit.edu | K.Michael.Kohl@gmx.de |
| Work: +1-617-253-9207 | Home: +1-617-629-3147 |
| Fax: +1-617-253-9599 | Mobile: +1-978-580-4190 |
| http://blast.lns.mit.edu | |
+-------------------------------------+--------------------------+



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