-Review of hPz systematics:
-how is hPz obtained from d(e,e'p) quasielastic A_ed^V,
d(e,e'n) spin-parallel asymmetry, d(e,e'd) elastic, and d(e,e') quasielastic.
-what are the precise assumptions?
-statistical and systematic errors on hPz from the four reaction channels
-hPz vs. time for each reaction channel
-comparison of the four sources using the same dataset
-Variation of observables (A_ed^V, GEn, T11e/T10e, GMn) for the best
estimate of hPz and for the two most extreme values of hPz suggested by
the error
Minutes:
Review of hPz, systematics and impact on observables
AM: presented steps of the procedure to extract hPz, event selection,
background determination, kinematic corrections, asymmetries, fitting
with full Arenhoevel model. Uses two lowest pmiss bins to fit in any
given Q2 bin. Results show Q2 dependence. Enfavored is lowest Q2
bin, because: Lowest Q2 bin has smallest dependence on width of
missing mass cut. Only the lowest Q2 bin yields consistent values of
hPz in the left and right sector. Model dependence is smallest:
nuclear effects and FSI is negligible, hPz as extracted assuming
Hoehler-FF and treating data like ep elastic agrees well.
See slides for values of hPz (average is around 0.57 for 2004).
To-do-list:
-Apply CC's method to extract hPz along with proton-FF (treat
quasielastic data like ep elastic data).
-for elastic kinematics, different Q2 regions prefer different regions
of z: map hPz as a function of z (for chosen bins of Q2 and applied
pmiss cut)
-evaluate kinematic corrections: how is hPz affected as function of Q2
using the various correction sets (also relevant for the next meeting)
-radiative corrections, energy loss corrections: No radiative
corrections are applied yet in MC, effects need to be
quantified. Energy loss corrections are not explicitly applied to the
reconstruction, however they are effectively hidden in the "kinematic
corrections". E-loss in MC??
-smearing of Montecarlo variables for realistic resolutions: both
generated angles and momenta should be smeared such that derived
quantities such as Q2, Mmiss get realistic resolutions.
-Anyone who needs hPz for a particular runlist should become able to
derive the number using Aaron's macros, including proper handling of
background.
VZ: presented hPz as determined from d(e,e'n) in kinematics with spin
parallel to q. In this case, the form factors mostly drop out of the
asymmetry which is simply determined by kinematic factors and
hPz. However, nuclear structure and FSI effects are larger in case of
(e,e'n), so again the full Arenhoevel model was used to extract hPz.
Showed hPz as a function of time of the 2004 dataset. Time dependence
agrees well with AM's extraction, number is slightly (1sigma) higher
(around 0.6). Impact on GEn: varies with Q2 and pmiss as the raw
asymmetry changes sign because of non-perpendicular kinematics. It is
about 0.5% on GEn per percent change of hPz.
NM: showed plot of hPz from inclusive quasielastic (e,e') vs Q2 for
both sectors, using Arenhoevels full model (with dipole form
factors). Agreement between left and right very good, almost
independent of Q2. Extracted value of hPz is ~0.52, somewhat smaller
than AM's value. NM's GMn extraction from the super left/right super
ratio is of course independent of hPz. However, the cause for the 10%
discrepancy needs to be understood better. NM is using a somewhat
different runlist which could explain part of it.
To-do:
-evaluate hPz for different form factors: H.A. needs to be contacted
to provide a set of calculations with a more appropriate prescription
of the form factors than dipole, e.g. with the Friedrich-Walcher fits
of the FF.
PK: showing hPz from fits to ed elastic scattering asymmetries from
vector-polarized deuterium. Assuming Abott's parameterization of the
deuteron form factors, quite good statistical errors are obtained,
with a value very consistent with AM's. Impact on observables T11e,
T10e is on the order of 1%/percent of hPz variation.
To-do:
-use CZ's global fit instead of Abbott once it is available
Everyone should make his slides available that were shown at the
meeting. I apologize that writing to the new disk area is still not
possible. So, please send me your slides or links to their locations
and I'll take care of it this time. The new webpage will contain a
directory for every analysis meeting, were all the slides are
accessible and where also a copy of the minutes will be found.
The ordering of the coming two meetings has been changed: We will
review "kinematic corrections" next Wednesday 6/22 and then focus on
radiative correction the week after, on Thursday 6/30 (not Wednesday),
i.e. the day of the Bates cookout.
Questions and comments are welcome.
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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