GEANT-based momentum resolution table

[David Lawrence <davidl@jlab.org>]

Hi All,

    I have placed a table containing the most recent momentum resolution 
results from GEANT-based studies in the repository. It is in the form of 
a ROOT file(~8MB) and some code to read it. There is an example program 
called hdparsim.cc with some detailed comments which should get you 
started. The main feature is a routine of the form:

bool Smear(int geanttype, TVector3 &mom);

which takes the geant particle type and initial momentum as input and 
overwrites the momentum values with ones smeared randomly according to 
the resolution for the given inputs. The return boolean can be used to 
decide whether or not to keep the event based on the reconstruction 
efficiency for the given inputs.

At this point, the geanttype value is ignored and are there only for 
future expansion. The format was designed such that we will expand it to 
include an option to derive the resolutions from parametric calculations 
where possible design modifications can be more easily incorporated.

To get the code do this:

svn co 
https://halldsvn.jlab.org/repos/trunk/src/programs/Simulation/HDParSim

Please let me know if you have any questions.

Regards,
-David

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  David Lawrence Ph.D.
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