Hi,
here are the minutes:
-Assessment of v3_4_17 recrunch
v3_4_17 lrd recrunch done for hydrogen and deuterium 2005
Difference to v3_4_16 has been the extended magnetic field map.
-Adrian showed plots of kinematic offsets that indicate consistency
between small and large grid result.
-The observed offsets of th_p-th_p(th_e) and p_e-p_e(th_e) cannot be
simultaneously accounted for by an offset of th_e (would need
different signs for such an angle offset)
-Adrian's plots of z: blue=pleft, magenta=corresponding eright;
red=pright, green=corresponding eleft. Red/green pair consistent with
each other but differs greatly from blue/magenta (which is consistent
with each other). Reason was attributed to an inefficiency due to
losses in the cuts (those were not updated and were still valid for
the version before the latest geometry changes)
-Adam showed comparisons of d(e,e'p) data and MC for 2005 deuterium
of the old crunch v3_4_14 (lrn) from January and v3_4_17 (lrd)
from today. Plots show electron momentum in the left and right
sectors (columns) for 0.1<Q2<0.2 and 0.2<Q2<0.3 (plot containing
"1_3" in the filename) and 0.3<Q2<0.4 and 0.4<Q2<0.5 (plot
containing "3_5" in the filename). The agreement in the right sector
has improved considerably. The left sector has been affected only
little. The MC still shows broader distributions than the data,
indicating an issue with the resolution. Best agreement was achieved
for lowest Q2 bin, while the higher bins show discrepancies. In
general, the momenta of the data are smaller than those of the MC
which could be partially or potentially explained by radiative
effects.
-Chris generated code that calculates derivatives of p,th,ph,z with
respect to geometrical offsets of r,theta,phi,alpha,beta,gamma of the
chamber locations. With the three chambers in each sector treated as
a rigid object, there's a total of
2 sectors * (3 positions + 3 angles) = 12 parameters that can be
varied to find the most likely wire chamber geometry in a fit linear
in the offset parameters. There's a total of 12 constraints from
imposing elastic kinematics (2 sectors) * (vertex + coplanarity + 3
independent kinematic relations of momenta and angles +
time-of-flight relation), therefore the linear fit should have one
unique solution. (It's actually a linear regression).
Before imposing elastic kinematics constraints, the average effects
of energy loss and internal radiation on the momenta have to be
accounted for first.
Eugene had parameterized the momentum losses of protons and electrons
by comparing the MoneCarlo momenta with energy loss turned on with
the tossed momentum, as a function of reconstructed momentum (email
from March 10). However, internal radiation (MASCARAD) was turned
off. This should be repeated as also the average momentum of the
electron due to internal radiation gets shifted as a result of the
finite resolution. Adrian had shown this in his comparisons of
radiated and unradiated Montecarlos in the meeting of 2006/03/01.
Needed are really parameterizations of delta p between (radiated +
energy loss)-MC and tossed momenta. Eugene, Adrian, this is input
that Chris needs while working on the procedure to find the optimum
wire chamber locations and orientations.
-Strategy for coming steps / to do list
The strategy is two-fold: While we (Chris) continue to determine the best
geometry we also have to prepare for the April 6/7 collaboration
meeting. Therefore:
+For the current recrunch version v3_4_17, the currently
corresponding residual kinematic offsets along with separate
parametrizations for electron radiation loss and proton
energy+radiation loss have to be determined and suitably
parameterized and be made available for everybody's use in
blast_anaware, (with energy/radiation loss separately accounted
for) (-> Eugene, Adrian). This has a very high priority.
+v3_4_17 in combination with the above corrections will be the data
basis for analysis updates that are going to be reviewed on
April 6/7.
+I will continue the v3_4_17 recrunch for deuterium 2004 asap.
By early next week (~03/27) the v3_4_17 recrunch of the entire data
should be available (hydrogen and 2005-deuterium is available
already), along with the corrections from above. From
then on, 10 days will be available to revisit cuts and macros to
update the analysis results. Cuts can be looked at already from now
on. In particular, it is desirable to have new estimates for th_d,
hPz and Pzz by the end of next week (Sunday April 2, 2006), with
three days left to apply them to the analyses.
+Chris will determine the optimum wire chamber geometry by early next
week. Hopefully I will be able to crunch the hydrogen data with
the updated geometry before next Wednesday. If we're satisfied with the
results, plan will then be to perform another recrunch of the entire
dataset and to produce the "residual kinematic corrections" on top.
+This recrunch will be available by mid-April at the earliest.
"Final" (presentable and publishable) analysis results are then
envisioned for end of April.
-Collaboration meeting is on Friday 2006/04/07 09:00 at Bates
-Extended analysis meeting on Thursday 2006/04/06 09:00 at Bates
-Next analysis meeting is on Wednesday 2006/03/29 13:30 at Bates
Best regards,
Michael
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