[G12] Fwd: Meeting reminder

[Andrea Celentano]

Hi MK, concerning the email, usually I get errors when sending emails to g12 due to the too large mail size, requiring the moderator to approve my email.
I'll do what you ask concerning the momentum corrections during holidays.
BestsAndrwa
-------- Messaggio originale --------Da: "Michael C. Kunkel" <mkunkel at jlab.org> Data: 19/12/18  21:00  (GMT+01:00) A: Andrea Celentano <andrea.celentano at ge.infn.it>, g12 <g12 at jlab.org> Cc: lguo <lguo at jlab.org>, "Hicks, Kenneth" <hicks at ohio.edu> Oggetto: Re: Fwd: [G12] Meeting reminder 

    Greetings Andrea, 

    
    It seems that I did not get this email even though you cc'd g12..
    Thank you Lei for forwarding it.

    I have a few questions about the fitted lines. Are the
    representations derived from a projection plot or fitted to the 2D
    spectrum?

    Also, about the phi corrections, this shape looks very familiar.
    Could you do the trivial task of applying the g12 momentum
    corrections then comparing the phi of the photon before and after?
    As a refresher to the rest of g12, the momentum corrections were
    basically a phi correction, see the write-up.

    

    Otherwise, I am glad that the lepton parameters of the fitter
    worked. I was not able to track down why the pion parameters didn't,
    as the fitter still works well for me.

    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
    On 12/19/18 4:20 PM, lguo wrote:

    
    
      
      

      

        
          Begin forwarded message:
          

          From: Andrea Celentano <andrea.celentano at ge.infn.it>

            
          Subject: Re: [G12] Meeting
                reminder

            
          Date: December 19, 2018 at 4:39:29 AM EST

            
          To: lguo <lguo at jlab.org>

            
          Cc: g12 <g12 at jlab.org>

            
          

          

          
        
      
      Dear G12,
      I’ll be on a train starting from 10AM JLAB time,
        hence I don’t know if I’ll be able to join the meeting - will
        try, but I don’t know about the quality of internet connection
        via phone.
      

      
      Concerning meeting time next year, these are my
        options:
      

      
      Monday: from 8 AM to 12 AM
      Tuesday: from 8 AM to 12 AM
      Wednsday: from 8 AM to 11.30 AM
      Thursday: from 8 AM to 11 AM
      Friday: from 8 AM to 11 AM
      

      
      Concerning g12 photons, I realized that is not
        trivial to isolate in the dataset a clean sample of gamma p
        -> p pi+ pi- gamma events. I was relying on kin. fit to do so
        (as done by D. Keller for his g11 corrections), selecting events
        with an high (>15%) CL for the gamma p -> p pi+ pi-
        (gamma) hypothesis and a low (<1%) CL for the missing pi0
        hypothesis. However, when comparing the measured gamma with the
        kin.fit missing gamma, I saw very broad distributions.
      

      
      Therefore, I tried to repeat the procedure on the
        reaction gamma p -> pi pi0 -> p e+ e- gamma. I used the
        same skim as before, assigning to pi+ the e+ mass and to pi- the
        e- mass and correcting the energy (not the momentum), as
        suggested by MK. I saw a clean pi0 peak in the missing mass on
        the proton, and I selected events by applying a 2C kin. fit on
        the gamma p -> pi e+ e- (gamma) hypothesis, constraining the
        e+ e- gamma to form a pi0.e
      

      
      After doing so, I was able to select a very clean
        set of events. The pulls and the chi2 prob. distribution look
        fine. I am now in the process of deriving the corrections. I
        attach a screenshot showing the difference between missing
        photon energy/angles minus measured photon energy/angles as a
        function of the missing photon quantities. 
      

      
      Bests,
      Andrea
    
    

  
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