[Primexd] [EXTERNAL] PrimEx Meeting Friday, April 24 at 1PM EDT

[Shepherd, Matthew]

ig,

Could you report on this at the calorimetry meeting this week?  It would be good to talk about your findings in the fiducial volume.  I don't doubt a problem at the innermost ring of glass, which will take special care if you need to reconstruct photons there (as you might for PrimEx).  For the fiducial volume, please take care to decouple position and energy correlations.

There are known angle dependent effects because at larger angles you alter the angular distribution of Cherenkov photons inside the block.  This will not be in simulation as there are no Cherenkov photons.  However, the effect is, in principle, in data,  And because we fix the pi0 mass on a block by block basis, this could introduce a small position-dependence on the gain constants due to this effect that propagates back to a position dependence of the simulated threshold in the MC.  This effect is pretty small though over the GlueX range of angles -- see Fig. 2 of the following paper

https://urldefense.proofpoint.com/v2/url?u=https-3A__doi.org_10.1016_j.nima.2006.07.061&d=DwIFAg&c=CJqEzB1piLOyyvZjb8YUQw&r=lU05Rh9aCuulfMNDTEUwlg&m=0Jkmdq-Lg5yCcNH_7khZGLWHgPTn--S3SjXXhGAjI7w&s=3Bc6yk6b0RBIHaKa5cuBw5EJY4OmQLX6Zrt13f06qpQ&e= 

I can't imagine a threshold variance of a few percent of itself is enough to make a signficant difference since it is only affecting the lowest energy hits.  I don't know if have any evidence of this effect being present in data.

Matt



On Apr 27, 2020, at 12:23 PM, Igal Jaegle <ijaegle at jlab.org<mailto:ijaegle at jlab.org>> wrote:

Thank you Matt for the explanation and slides. Looking at pi0, not only in the fiducial volume (~20 cm < r < ~100 cm), but outside of it, is probably exposing cracks in the current simulation scheme. Unfortunately, we need the inner rings

tks ig.
________________________________
From: Shepherd, Matthew <mashephe at indiana.edu<mailto:mashephe at indiana.edu>>
Sent: Monday, April 27, 2020 5:54 AM
To: Drew Smith <andrew.p.smith at duke.edu<mailto:andrew.p.smith at duke.edu>>; Igal Jaegle <ijaegle at jlab.org<mailto:ijaegle at jlab.org>>
Cc: primexd at jlab.org<mailto:primexd at jlab.org> <primexd at jlab.org<mailto:primexd at jlab.org>>
Subject: Re: [Primexd] [EXTERNAL] PrimEx Meeting Friday, April 24 at 1PM EDT


Drew and Igal,

I was looking through your slides and also there is the thread of Igal's comments about hit level gains.  I see Drew noticed some G3/G4 differences in number of hits.  Which one is "right" depends on data.

As I noted to Igal, this was studied and tuned in G4.  It is particularly important to get low-energy response correct when writing the algorithm to reject hadron interactions.

See slide 9 of this:

https://halldweb.jlab.org/DocDB/0040/004084/001/MC_NeuralNet_Updates.pdf

Also the checking of energy response in G4 is illustrated on slide 14 of that same talk.  You can see the reconstruction of the photon gun works just fine.  This suggests a discrepancy between Igal's plots and these photon gun results, perhaps somehow related to the use of a pi0?  ...or something has changed.

Matt


On Apr 23, 2020, at 7:25 PM, Drew Smith <andrew.p.smith at duke.edu<mailto:andrew.p.smith at duke.edu>> wrote:

Dear All,


The next PrimEx meeting will be tomorrow, April 24, 2020 at 1 PM (EDT). Here is a link to the meeting page, please add to the agenda if you have any updates:

https://halldweb.jlab.org/wiki-private/index.php/April_24,_2020_PrimEx-Eta_Meeting

Here is a link to the bluejeans meeting page:
https://urldefense.proofpoint.com/v2/url?u=https-3A__jlab.bluejeans.com_7572695553_&d=DwIFAg&c=CJqEzB1piLOyyvZjb8YUQw&r=lU05Rh9aCuulfMNDTEUwlg&m=0Jkmdq-Lg5yCcNH_7khZGLWHgPTn--S3SjXXhGAjI7w&s=abUlF3ijnyTpj03zHhqwVt15ct6MG9y7QVPxqXcvOHo&e= <https://urldefense.proofpoint.com/v2/url?u=https-3A__jlab.bluejeans.com_7572695553_&d=DwMFAw&c=CJqEzB1piLOyyvZjb8YUQw&r=lU05Rh9aCuulfMNDTEUwlg&m=2mdSf37sXaUkuO5zaQ0H5-oYP2gQZRhMv7575tlmmOA&s=ZkRSLDXTBkghWzZmC9BynODrAystctRBSVCaBKby434&e=>


Best,
-- Drew

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