[clas12_rgk] [EXTERNAL] Re: lides for CLAS collaboration

[Annalisa D'Angelo]

Dear Izzy,
very nice talk. I tend to agree with FX: you may state that work is in 
progress within RG-K working group to assess the correlation between 
chi2 from REC::Track and signal/background ratio in pi+ pi+ p events.

All the best
Annalisa
Il 09/11/21 04:02, Izzy Illari ha scritto:
> 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
>
-- 
================================================
Prof. Annalisa D'Angelo
Dip. Fisica, Universita' di Roma "Tor Vergata"
Istituto Nazionale di Fisica Nucleare
Sezione di Roma Tor Vergata, Rome Italy
email:annalisa.dangelo at roma2.infn.it
Jefferson Laboratory, Newport News, VA USA
Email: annalisa at jlab.org
Tel: + 39 06 72594562