[G12] My multiple beam photon study

[Michael Paolone]

Hi MK, All,

This looks reasonable, and I think I can explain the energy dependence. 
The key is that all events have to fire a trigger whose efficiency is
dependent on the momentum and angle of the tracks created from the
reaction which itself IS photon energy dependent.

Look at the 1 photon probability plot and ask how likely is it that that
photon is the one that created the trigger.  For very low energy photons
the overall trigger efficiency drops, and since we see an event at all, it
becomes more likely that another higher energy photon in the same beam
bucket generated the reaction that triggered the event.

The sharp jump at 3.6 GeV shows that the event is now more likely to
trigger with just that photon (since that's where the primary trigger
starts).

The downward slope after 3.6 GeV might again be a trigger efficiency
effect, where it becomes more likely that we lose small angle tracks down
the beam hole which could have fired the trigger.

-Michael

> Greetings,
>
> I did not want to show this last night because I thought there was a bug
> in my code. But I do not think I have a bug in my code, so I want to
> show you what I concluded.
>
> First of all, my result does not agree with the values found by FSU or
> FIU. I actually see a strange dependence on energy. What I am depicting
> are plots of the probability of multiple photons within the same bucket
> as clasEvent choose ±1.002 ns, meaning the photon energy on the X-axis
> of the plots are of clasEvent chosen, which was the best timed beam
> photon compared to the average _of_ start times.
>
> The data used for this is only the 566* runs, which is approximately 7%
> of the data.
> Please see:
> https://clasweb.jlab.org/rungroups/g12/wiki/index.php/TAGR_code#March_31
>
> --
> BR
> MK
> ----------------------------------------
> Michael C. Kunkel, PhD
> Forschungszentrum Jülich
> Nuclear Physics Institute and Juelich Center for Hadron Physics
> Experimental Hadron Structure (IKP-1)
> www.fz-juelich.de/ikp
>
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