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

[Michael Dugger]

Eugene,

Thanks for catching that. I think I have pion angles instead of proton.

I am going to back over the code to fix this.

Take care,
Michael

> 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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>> >>>
>> >>
>> >> _______________________________________________
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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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