Attending AM,NM,AS,CZ,VZ,TA,TB,MK,BT,SS
AM: d(e,e'p)
-rewriting his analysis library
-more reliable estimate for hPz by taking acceptance into account.
Previous show_ep_asym.C used point-like calculation only.
Subsequently, hPz may shift by 0.03-0.05 to smaller value.
-follows sugg. by ZZ to plot asymmetry vs. angle between deuteron
orientation and direction of pmiss (in PWIA this is the proton initial
momentum). TB suggests to look at asym. vs. components of pmiss along the
deutron spin direction and transverse to it, this would map the shape of
the deuteron wave function components
NM: d(e,e')
-discovered that command line call of root accepts only up to 256
arguments, relevant to long runlists. Instead of manual insertion in the
command line, it is suggested to read in a runlist by a macro from a text
file.
-shows spectra of omega and of (omega-Q2/2m) for certain bins of Q2
compared to MC. Initial confusion that radiated data has
centroids at smaller omega than unradiated MC. Can be explained by
applied cut and overall normalization of data/MC. Discussing effect of
radiative tail in the data (qualitatively understood).
-shows inclusive beam-target asymmetry for e-right (=spin-parallel) and
e-left (spin-perpendicular) vs. Q2, shows sensitivity to GMn variation.
-previous big discrepancy between data and MC gone after fixing the
"commandline issue" from above
-sensitivity of asymmetry to spin angle is 0.001 per degree or dA/A of
0.5-1% relative
-suggested to check sensitivity to variation of GMn also for e-left data.
-discussing radiative corrections: software and plot provided by Afanasev
show that radiative effects on the asymmetries are very, very small!
CZ: d(e,e'd)
-rewriting analysis code
-z-profile of spin angle variation: was measured for 47 degree spin angle.
At present, CZ extrapolates to the 32 degree case. Variation along z is
on the order of 3-4 degrees, accuracy of determining the average spin
angle is +- 1 degree. Best spin angle value for "32" degree data is 31.5
degrees.
-sensitivity of asymmetry to spin angle is 0.01 per degree or dA/A of
3% relative
-reconstruction issues/wire chamber calibration at very forward angles:
blow-up of Q2 resolution at very low Q2. Issue with t2d in that region.
-is presently not working on this
AS:
-holding field produces a shift in phi at phi!=0 up to 3 degrees, has
not been accounted for yet in reconstruction.
-two plots of beam-target asymmetries of p(e,e'pi+) vs. W, data compared
to MAID. hPz assuming MAID consistent with hPz from ep elastic.
-data shows feature of 5% momentum correction for e-left electrons, like
seen as well in (e,e'), (e,e'd), (e,e'p), (e,e'n).
-will present slides for e,e'pi+ event selection, cuts, issues next time
-p(e,e'pi+) data is very clean!
-future:p(e,e'p)pi0, p(e,e'n)pi+
The next meeting will have a focus on kinematical corrections of p_e,
th_e, p_p, th_p, and on the recrunch situation
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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