Hi,
below are the minutes of this week's analysis meeting.
We meet again on Wednesday July 05, 2006 at 13:30 at Bates.
Minutes
-Pion electroproduction from hydrogen (Aki, see ppt)
+p(e,e'pi+)n, p(e,e'p)pi0 yields and single+double spin asymmetries
+Comparisons with MAID2000, MAID2003, DMT2001
+Montecarlo yields of MAID2003 in each sector separately normalized
to data, same normalization applied to MAID2000 and DMT
+Yield difference between left and right sector 30-40% (eright higher)
+piplus channel: good agreement between data and MC for beam-,
target- and beam-target asymmetries
+pi0 channel: seemingly large background from elastic radiation tail
(ca. 50% of yield within missing mass cut), however asymmetries
agree with MC for pure pi0 production. If there is significant
elastic radiative background, (double) asymmetries would be shifted
towards negative values
+Shape of radiative background distribution in missingmass^2 spectrum
could/should be sampled with elastic event selection (impose
coplanarity and theta-angle correlation)
+Shape of radiative background distribution in missingmass^2 spectrum
could/should be simulated with Mascarad
-ep elastic update (Adrian, not discussed today, see gif's)
+Included spin angle map bin-by-bin
+will evaluate systematic error from Q2 difference electron vs. proton
-ep quasielastic followup (Adam, not discussed today, see ppt)
+applied EG's momentum corrections
+Displays p_e - p_e_calc after correction, overlayed total and pm<0.1
+Quality of correction is better in quasifree limit. Remaining
discrepancy likely due to angle offset, still to be accounted for
-Miscellaneous:
+EG's kinematic corrections, final version needed
-EG to arrive today, work with VZ on simulation
+MS resumes work on time calib
-Problems with cosmics/flasher calib for
2004 hydrogen/ 2005 deuterium will be fixed
-Recrunch on top to finalize e,e'n analysis
+Richard/Elba meeting:
-Isoscalar/isovector form factors: Extraction from BLAST with
identical binning in all channels -> EG,VZ: what's the binning ->
CC,AS extract GEp,GMp; AD,RF extract GEp,GMP; MK extract GM with
same binning, upper Q2 limit by GMn (using Cerenkov)
-Two-photon effects, Afanasev calculating
-Remark that Jlab experiment will likely not give definitive answer,
better use storage ring with high positron intensity
-Proposal for Desy PAC Oct 12-13, 2006, J. Arrington interested
-Positrons available at Doris
+Meeting with Bonn group on July 28, 2006, MK preparing agenda
-Two-photon physics should also be generally discussed, to what
extent possible in Bonn (no positrons)
+Blast collaboration meeting on Friday 7/14 at Bates, will send out
preliminary agenda soon
+Proton GEp/GMp draft reviewed by MK, back in hands of CC/HG
+MK currently reviewing T11 draft; for this purpose, I had a long
conversation with T.W. Donnelly on Tuesday. We agreed that it is
important to verify the expressions for the polarization
observables used in the draft. In particular, it is important to be
clear about signs (most importantly for T21 and T11), coefficients
(from normalization of form factor definitions), factors of i
(Madison convention), etc. Donnelly's review article(s) are reliable
references. Problems only occur when comparing one reference using
one set of conventions with other references using other
conventions. I'm in the process of finding relations between
Donnelly's nomenclature in the 1984 review withI. Sick (F_i's for
form factors and R_i^j's for polarization observables) and commonly
used ones such as the G's or T_ij's.
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