[Sane-analysis] Type 4 from ntuple vs Beta2 scalers

[O. A. Rondon]

Hi,

I have plotted the raw asymmetries for the 4.7 GeV 80 deg. data vs run,
calculated directly from the Beta2 scalers (which I've posted before)
and from the ntuple, cutting only on type 4 triggers (from James'
tables), see left panel at
http://www.jlab.org/~rondon/sane/analysis/asym/All_beta2_trig_4_7_80_2.pdf

There is very good agreement, although there are some systematic
differences. Excluding runs 72884 and 72889 which as the plot shows are
clearly different, the ratio of type 4/Beta2 asymmetries is 11% higher
on average, with a 5% larger average error. This disagreement may be
worth understanding, I haven't investigated. However, the main point is
that the scalers and ntuple agree in tracking the Pb*Pt product.

On the other hand, the charge and livetime normalized type 4
asymmetries, with the prescription that works to remove the false
asymmetry for parallel non-ammonia runs, seems to still show a residual
false asymmetry, see top right panel.

But not swapping the helicity labels for LT gscaler(538) results in a
clearly worse departure from correlation with the Pb*Pt product (all
asymmetries become negative). The charge normalization plays a minor
role, but things are also slightly worse without swap.

There seems to be a worse false asymmetry for there 80 deg. runs than
for the parallel data. Excluding runs with LT < 0.67, bottom right
panel, things become a bit clearer: the correlation with Pb*Pt could be
restored by subtracting a residual false asymmetry of ~0.45%. I believe
this is consistent with Hovhannes observation that the false asymmetry
for 5.9 GeV 80 deg. runs was larger than the one I got for parallel data.

Mark's recalibration of the BCMs and replaying with the updated clock
scalers should clarify some or much of the problem, but I am convinced
a zero asymmetry of the non-NH3 runs will be the touchstone of our analysis.

Cheers,

Oscar