[Frost] [EXTERNAL] Re: Follow up of last FROST meeting

[Eugene Pasyuk]

Mike, 

The vertical axis can't be right. The proton can't go backwards in the lab system

-Eugene

> -----Original Message-----
> From: Frost <frost-bounces at jlab.org> On Behalf Of Michael Dugger
> Sent: Monday, December 23, 2019 14:07
> To: Stuart Fegan <s.fegan.glasgow at gmail.com>
> Cc: frost at jlab.org
> Subject: Re: [Frost] [EXTERNAL] Re: Follow up of last FROST meeting
> 
> Hi,
> 
> Chan is just trying to answer questions raised about a possible momentum
> cut. I suggested that he look at where his events are in terms of kinematic
> bins he will report on. My idea was to see if pushing up the momentum cut
> to perhaps 400 MeV would cause any issues within his kinematic binning.
> 
> I just made a plot that can be found at
> 
> https://userweb.jlab.org/~dugger/pi0PphaseSpacePlot.png
> 
> that shows the lab angle versus lab momentum for protons coming from the
> reaction gamma p -> p pi0. The black curves are for constant photon energy
> and the blue curves are for constant proton center-of-mass cosine values.
> 
> The above plot would have to be verified but it looks like there is no need to
> worry about low momentum protons.
> 
> The idea I had was for Chan to produce this type of information using real
> data, but I did a poor job of explaining what I meant.
> 
> I was trying to make life easier, but perhaps did not accomplish that :(
> 
> Take care,
> Michael
> 
> > Hi Chan,
> >
> > I'm going to chuck my two cents in, and reply to the FROST list,
> > because I missed the meeting last week.  Given the pion is
> > reconstructed from the proton missing mass, what's the motivation for
> > looking at proton momenta below the threshold where it can reliably
> > reconstructed in CLAS as a proton?  Is this to tune the cut, perform
> > systematic studies, or is there a physics motivation here that I'm missing?
> >
> > Cheers,
> >
> > Stuart
> >
> > On 23/12/2019 11:47, Michael Dugger wrote:
> >> Chan,
> >>
> >> It is a bit of a data dump.
> >>
> >> What is your binning going to by for the analysis? Are you really
> >> going to report values for E_gamma near 400 MeV?
> >>
> >> On slide 3 you show MM^2 and state that MM^2 for p < 280 MeV/c don't
> >> look like the others. I'm not convinced that you can say much about
> >> the MM^2 shown above p = 280 MeV/c.
> >>
> >> For your previous presentation:
> >>
> >>
> https://clasweb.jlab.org/rungroups/g9/wiki/images/9/94/FROST_2019_12_
> >> 18.pdf
> >>
> >> on slide 2 you had a nice fit to the MM^2 distribution where you
> >> pulled off a pi0 mass. Are you able to do that for the low momentum?
> >> Is it possible that you can not pull out any pi0 from the low
> >> momentum data? I just do not see any pi0. Am I missing something?
> >>
> >> Take care,
> >> Michael
> >>
> >>>
> >>>
> >>> Dear FROST run group,
> >>>
> >>> Hello, below is a link to my slides for follow up of last FROST
> >>> meeting(12/19):
> >>>
> https://clasweb.jlab.org/rungroups/g9/wiki/images/e/ed/FROST_2019_12
> >>> _22.pdf
> >>>
> >>> 1. Distributions of kinematics (MMSQ, dt, d\beta) for particles in
> >>> lower momentum ranges are plotted to see whether lower momentum
> >>> particles are of any use for my asymmetry calculation.
> >>>
> >>> 2. Proton selection, using beta difference, was revised to a simpler
> >>> version where static cuts on beta diff are applied at +/- 0.06
> >>>
> >>>
> >>> Thank you,
> >>> Chan
> >>>
> >>> _______________________________________________
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> >>> Frost at jlab.org
> >>> https://mailman.jlab.org/mailman/listinfo/frost
> >>>
> >>
> >> _______________________________________________
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> >> Frost at jlab.org
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> >
> > --
> > Dr Stuart Fegan
> > Honorary Research Associate
> > Nuclear Physics Group
> > University of Glasgow
> > (Currently at the University of York)
> >
> > E-mail: s.fegan.glasgow at gmail.com
> >
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> > https://mailman.jlab.org/mailman/listinfo/frost
> >
> 
> 
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