[Halld-npp] Minutes posted and the Overleaf document has been updated

[Mark Ito]

Folks,

I did a capture into GitHub of the document on Overleaf just now. For 
convenience, I created a PDF of this version which you can find at

https://userweb.jlab.org/~marki/share/Pi0Polarizability_2020-06-12.pdf

   -- Mark

On 6/12/20 5:08 PM, Elton Smith wrote:
> Dear collaborators,
>
> I have posted some minutes of today's meeting on the wiki at 
> https://halldweb.jlab.org/wiki/index.php/Pi0_Polarizability_Meeting_Jun_12,_2020#Minutes.
>
> I have also updated the draft on Overleaf with the latest changes. 
> Please provide feedback as soon as possible so that we can post an 
> update for the collaboration early next week.
>
> Note: I updated the summary plot (Fig. 29 of the proposal). We state 
> that the (statistical) uncertainties are obtained directly from the 
> fit (Fig. 21). It turns out the AmpTools fits provide very reasonable 
> errors near threshold where the statistics are large, but give very 
> small uncertainties at high mass. If we use the fitted statistical 
> uncertainties directly, I get the attached plot. One can see that at 
> large masses, the uncertainty converges to the 5% systematic 
> uncertainty. There are only 10-20 Primakoff-pi0pi0 events in this mass 
> region. This is very likely an underestimate of the true statistical 
> uncertainly. [Note that this is a well-known fact of the output of the 
> Amplitude fit.] Therefore, I have produced a hybrid plot, where I use 
> fitted errors where the statistics is large and the "naive" 
> statistical uncertainty if the fitted uncertainty is very small. The 
> plot that is included into the document uses the latter strategy. We 
> can talk about this next week.
>
> Cheers, Elton.
>
>
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