[G8b_run] mom corr function and histos

[Charles Hanretty]

Hello all,
     Here is my momentum correction function and array again.  You can find 
it at:
/u/home/hanretty/rootbeer2.1/NTuple_code/corrected_proton_mom.cc

the array needed can be found at:
/u/home/hanretty/rootbeer2.1/NTuple_code/mom_corr_array.pro

The function requires you to give it the proton's 4-vec as it
comes from the data file, no corrections should be made to this 4-vec 
prior to the call to the function.  This 4-vec is used to find the correct 
bin in momentum, theta, and phi and the appropiate correction factor.  The 
function also needs a 3-vec vertex position and the run number.  The 3-vec
and run number are needed to apply the ELoss package to the 4-vector both 
before the corrections are applied and after. This function does not
apply ELoss twice to the same 4-vector though.  ELoss is first applied to 
the 4-vec so the binning can be determined.  The correction factors are 
then applied to the (raw) 4-vec components and the momCorred 4-vec then 
has ELoss applied to it.  The function then returns the corrected 
4-vec.

I have also made some plots for tht tagger sag using a different 
confidence level cut and also the suggested mm^2 cut.  The first of the 
two plots I'd like to share show the taggerSag distributions using a conf 
lvl cut of 10% and 0.1%. In the histo, the lower distribution comes from 
using a conf lvl cut of 10% while the upper comes from using a conf lvl 
cut of 0.1%.  The low points of the two distributions are almost the same 
but the "humps" of the distribution using the lower conf lvl cut are more 
pronounced:
http://hadron.physics.fsu.edu/~hanretty/Files/TaggerSag/EtrueMinusEmeas_v_Emeas_FitMeans_BothConfCuts.gif

The second plot again has two taggerSag distributions.  The bottom one is 
the original dist (the one using a conf lvl cut of 10%) and the top one is 
the distribution made using the mm^2 cuts that were suggested by Mike. 
The effect of this mm^2 cut is almost exactly the same as the effect from 
making a conf lvl cut of 0.1%:
http://hadron.physics.fsu.edu/~hanretty/Files/TaggerSag/EtrueMinusEmeas_v_Emeas_ConfCutAndMM2Cut.gif

-Chuck