[G8b_run] mom corr function and histos

[Ken Livingston]

Hi Eugene, Mike,
I think we should have the meeting if possible. Can anyone initiate it, 
or does it have to be done by someone from Jlab.

Cheers,
Ken



Eugene Pasyuk wrote:
> Mike et al.,
>
> I'll be out of the country next week. If you decide to have conference 
> call next week, then someone else will have to initiate the call.
>
> -Eugene
>
>
> Michael Dugger wrote:
>   
>> g8b run group,
>>
>> Chuck: Nice job :)
>>
>> The run group should come to an agreement as to the energy and momentum 
>> corrections. It would be best if we all used the same corrections and had 
>> some sort of documentation to point to.
>>
>> My feeling is that a kinematic fitting routine should give the best 
>> results for this sort of study. Since replacing the confidence level cut 
>> with a missing mass cut does not change the results in any real meaningful 
>> way, the selection of events due to confidence level does not appear to 
>> be very important in the end analysis. As long as the pull distributions 
>> look good, I feel comfortable going with Chuck's results.
>>
>> Assuming that I read the plots correctly, Chuck's results suggest that the 
>> photon energies in the range of interest (0.9 to 2.0 GeV) are within 0.3 
>> MeV ! If this is the case, we do not need to worry about the photon energy 
>> correction and we state the width of an eid as being the uncertainty in 
>> the photon energy.
>>
>> Question: Should meet next week to discuss this?
>>
>> Take care,
>> Michael
>>
>> On Thu, 27 Aug 2009, Charles Hanretty wrote:
>>
>>     
>>> 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
>>> _______________________________________________
>>> G8b_run mailing list
>>> G8b_run at jlab.org
>>> https://mailman.jlab.org/mailman/listinfo/g8b_run
>>>
>>>       
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-- 
=======================================================
Ken Livingston          

Dept. of Physics & Astronomy,        Tel: +44 141 330 6428
University of Glasgow,               Fax: +44 141 330 5889
Glasgow G12 8QQ.
Scotland. UK.
=======================================================