Minutes of the Blast analysis meeting on Wednesday 9/06/2006

From: Michael Kohl (kohlm@mit.edu)
Date: Wed Sep 06 2006 - 16:22:10 EDT


Hi,

below are the minutes of today's analysis meeting.
Note that there will be no meeting next week.
The next meeting will be on Wednesday September 20, 2006 at 13:30 at
Bates.

Minutes:
+Status proton form factor paper
  -Minor changes left on figures and world data selection
  -Envision submission to PRL on Thursday (tomorrow)

+Path towards ed elastic results for T20,T21->GQ,GC; T11,T10->GM
  Prerequisites:
  -Finish v3_4_21 recrunch with improved timing,
   (2004=v3_4_18 old timing, 2005=v3_4_19 static timing) in principle
   good enough for ed elastic, but: holding field on, pathlength fixed
   only since v19.
  -Verify quality of timing calib before release ... 2 weeks ... 9/23
  -Checking runlists ...

  T20:
  -Update Chi's analysis (MK) -> T20,T21 ...??? 2 weeks ... 10/07
  -First draft existing
  -New paper of D. Phillips (nucl-th/0608036), Qd problem "resolved",
   precise predictions for GC/GQ and GC/GM, and for GC/GE(s),GQ/GE(s) and
   GM/GM(s) (normalized to isoscalar nucleon form factors)

  T11:
  -Update of ed vector analysis (PK): currently based on v18/19,
   utilizing T20 from Chi's thesis
  -Found factor sqrt{2} error in Eq. for T10
  -Found typo in Chi's thesis (sec(th/2) for T21)
  -Need hPz!!

+New meeting schedule
  -Every two weeks
  -Tuesday?? Wednesday?? Thursday??
  -Changing to Tuesday or Thursday would allow Bob to attend
  -Possible collisions: Bob teaching Wednesday, John teaching
   Tuesday-12:15, CAST seminar Tuesday 12:00 (not always), Bates stochastic
   cooling meeting Tuesday 15:00; Thursday colloquium 16:00
  -Would like to combine with Bates lunch seminar on the same day
  -As we'll move to a biweekly schedule, would like to allow for enough
   time for the meeting
  -Date 1: Tuesday 13:30
  -Date 2: Thursday 13:30, Bates lunch seminar at 12:00??
  -Date 3: Wednesday 13:30 (leave unchanged)
---> My vote is to move the meeting to Date-2.

Please let me know your preference/availability.

+Aob
  -Next collaboration meeting? Suggested Friday 11/17/2006

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 | |
+-------------------------------------+--------------------------+
-Status ffr paper
  +Text has been reviewed.
  +Figures still being updated, asymmetry plot has been updated.
  +Chris showing plots of GE and GM. World data should really be
   original published values for GE and GM from experiments that have
   really performed Rosenbluth separation on actual measurements (not
   global fit of other data)
  +Some authors combine their cross section measurements with existing
   measurements to perform Rosenbluth separation. For this letter,
   really only experiments from which a single-expperiment extraction is
   possible should be plotted.
  +Yet another discussion on how to extract the form factors GE and GM
   from the BLAST ratio measurement combined with previous cross
   section data. Fit versus equation solving. Discussion about nature
   of cross section error when using parameterization, statistical
   versus systematic. Although the error of the cross section has
   a statistical and systematic component, for the purpose of using it
   with the the BLAST ratio measurement to deduce the separate form
   factors from solving the equations, the character of the total cross
   section error becomes systematic (no fitting involved). However, in a
   fit method where GE and GM result from a fit to the ratio and the cross
   section values, it only works if the cross section error is treated as
   point-by-point statistically independent and statistical in its nature.
   And this exactly causes problems here when using a parametrization
   because the statistical fluctuation is replaced by an error band.
  +Will sort things out in offline phone meeting tomorrow at 4pm. Will
   use the Bates conference line +1-866-867-8301, passcode 4073393

-d(e,e'p)
  +hPz still Q2 dependent (~10% from lowest to highest bin). Possible
   origins: Diluted data sample (->check cuts); Resolution effects
   (->study effect of convoluting angles and momenta with finite
    resolution on asymmetry by varying resolution); or polarization
    profile along z corresponding to Q2 profile through correlation of
    z and Q2 (unlikely)
  +need to compare asymmetries and hPz vs z with MC with and without
   accounting for spin angle profile. Remaining variation of hPz with z
   could be due to polarization profile.
  +proton ff ratio from quasielastic d(e,e'p) at low pmiss (see plot in
   meeting directory) from super ratio. Ratio data from deuterium
   slightly below hydrogen data.
  +Friedrich/Walcher parameterization showing bump even for the ratio,
   in fact parameter Q_b for the location of bump is much smaller for GEp
   (0.07) than for GMp (0.35), therefore bumps in GEp and GMp seem not to
   cancel. However, Fig.3 in F.-W.'s paper shows bump at 0.2-0.3 GeV for
   all form factors. Something wrong in the Friedrich/Walcher paper? One
   should verify the fit to the data, like Chris did for Arrington's
   parameterization.

-Comparison of MC for different radiative generators
  +3 radiative generators available: Mascarad-dgen (Vitaliy), pionmc
   (Aki) and ElRadGen (Tavi+Sasha)
  +still bugs in implementation of ElRadGen, need more time
  +ElRadGen still unpolarize only
  +need to compare W spectra at generator level

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 | |
+-------------------------------------+--------------------------+



This archive was generated by hypermail 2.1.2 : Mon Feb 24 2014 - 14:07:33 EST