*****************************************
NOTES: Next "big" meeting friday 5/21 with
a focus on montecarlo
Yuan/Aki to start looking at epi+ channels
(following prev work by jason, chi)
*****************************************
_ Discrepancy Pz, Pzz (GT)
_ analyzed Pz in different vector states (uses beam hel flip)
Pz(V+) = 77+-6 Pz(V-) = -79+-6 Pz(T)= 2+-3 (all in %)
at the same time Pzz = 53 + 3
_ effect SFT inefficiency amplifies in Pzz realtive to Pz
_ Makes one possible scenario using values
MFT14:0.95 MFT34:0.98 sft:0.90 WFT:0.98
6-poles:0.95 unpol-stuff:0.98 depol:0.80
_ other choices possible... choose to play with the depolarization effect
_ Neutron timing (MK): see last meeting
_ Wch alignement (AM): _ tried various shifts (~ 5 mm) of all 3 changes
_ no effect on resolution of mc data
_ actually focus is on systematic shifts
_ Montecarlo (NM): _ not reconstructing L/R
_ must be a bug
_ Reconstruction:
=================
t2d: _ EG shows dx=(x0+x2+2x1) vs x1 cell by cell
_ "all" stub types included now
_ very forward cells dominated by stub crossing the
wire plane (close to at least one wire)
_ long discussion about discontinous dx due to sign assignement of wire hit
(i.e. stub type) note, while tdc distributin continuous
_ How can we minimize the effect of this ambiguity ?
_ need to apply varying weight to small Xdrift hits in newton (CC)
essentially ignore the 3rd hit if very close to wire (but use other 2)
_ CZ: can also flip small x_drift to see what fits best
Offsets:
_ Note: dx is still not centered at 0 which likely to be due to bad offsets
_ DH: this would also cause the banana shape for stubs 0,7
_ new(er) offsets may be needed
Resolution:
_ EG: Clearly worse theta:p correlation for electrons (forward region)
than protons
_ seems due mostly to e-momentum
_ selecting tracks only in linear region only possible at mid-chamber
_ but then the resolution not really seem much bettter
t2d and track angle correction:
_ CC,DH: still need to check current t2d with orignal Garfield
_ this to understand t2d(impact angle)
_ Otherwise t2d parametrization of track angle seems coded correctly!
action plan:
_ offset correction
_ weight at small xdrift
_ check garfield vs t2d
-- ________________________________________________________________________________ Tancredi Botto, phone: +1-617-253-9204 mobile: +1-978-490-4124 research scientist MIT/Bates, 21 Manning Av Middleton MA, 01949 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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