[clas12_rgk] lides for CLAS collaboration

[Francois-Xavier Girod]

Dear Izzy

> It would be more effective to use chi2pid for pass1 data

I disagree with the software group here, we do not want to do this. chi2pid
is based on rough studies done before pass1. We have much more extensive
data and know our detector response much better, including its time
dependence. We can do much better than chi2pid information

Furthemore, chi2pid does not include REC::Track chi2 information
The entire point of the charged particle studies was that we want to check
tracking quality
The tracking experts must correct this problem and provide us with a
reliable measure of chi2 and NDF

Best regards
FX

On Mon, Nov 8, 2021 at 10:02 PM Izzy Illari <izzy at jlab.org> wrote:

> Hello all,
>
> I intend to give an update at CLAS collaboration about fiducial cuts
> discussed in meetings:
> https://clasweb.jlab.org/wiki/images/b/b1/FiducialAnalysis_ILLARI.pdf
>
> I have spoken to Nathan and Raffaella & told the following:
>
> 1.) The chi2 from REC::Track is not well understood and it might not be
> very effective to cut on it for cleaning event samples
>
> 2.) There is a plan to fix this for pass2
>
> 3.) It would be more effective to use chi2pid for pass1 data, which is a
> signed Nsigma statistic that quantifies the difference between expected
> and calculated values. For electron/positrons it is based on sampling
> fraction in calorimeter, and for charged hadrons it is based on vertex
> time difference
> https://clasweb.jlab.org/wiki/index.php/CLAS12_DSTs#REC::Particle
>
> I imagine chi2pid could be fit with a gaussian and 5sigma and 3.5sigma
> cuts could be looked at to see how much they clean up event samples. I
> hope the chi2pid can be of some help to others in the group.
>
> Proton DC cuts have not been included due to issues with code.
>
> I would appreciate any additional comments.
>
> Thank you and all the best,
>
> Izzy
>
> --
> pronouns: they/their/them
>
> Physics Ph.D candidate (Feb 2020)
> Columbian College of Arts & Sciences, The George Washington University
> M.S. in Physics
> The George Washington University (Jan 2020)
> B.A. in Physics
> Barnard College, Columbia University (May 2017)
>
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>
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