[Primex2] Compton result from Li

[Gan, Liping]

HI, Ilya,

Please look at page 17 in his presentation. The top figure shows the extracted cross section and the bottom figure shows the ratio of the Monte Carlo event number per energy bin  over the photon flux.  Both distributions have quite similar shapes. On the other hand, one should expect the bottom distribution should only be related to the experimental photon flux and Monte Carlo Compton sample,  and it  has nothing to do with actually experimental Compton production. He said that he checked the photo flux distribution and found relatively smooth distribution. Therefore he conclude that the fluctuation in the figures on the page 17 might be caused by the Monte Carlo sample.

Liping 

-----Original Message-----
From: Ilia Larin [mailto:ilarin at jlab.org] 
Sent: Monday, February 15, 2016 3:11 PM
To: Gan, Liping
Cc: li ye; pawel; primex2
Subject: Re: Compton result from Li


 Hi Liping,
 There's no comments on his slides,
 what MC issue did he demonstrate?
 Ilya


----- Исходное сообщение -----
От: "ganl" <ganl at uncw.edu>
Кому: "li ye" <yeli.ciae at gmail.com>, "pawel" <pawel at jlab.org>, "Ilya Larin" <ilarin at jlab.org>
Копия: "primex2" <primex2 at jlab.org>
Отправленные: Понедельник, 15 Февраль 2016 г 14:51:28
Тема: RE: Compton result from Li

Hi, Pawel and Ilya,

Li demonstrated in his  presentation on last Friday that the fluctuation in his extracted Compton cross section might be caused by MC simulation sample. I think that it is very important. Would you please take a close look at his presentation? I would suggest to investigate the MC simulation as soon as possible.

Cheers,
Liping



From: Primex2 [mailto:primex2-bounces at jlab.org] On Behalf Of li ye
Sent: Friday, February 12, 2016 3:03 PM
To: Yang Zhang
Cc: primex2 at jlab.org
Subject: Re: [Primex2] PrimEx-II analysis meeting reminder

Hi powel , Ilia ,
Please take a look the slides I have for todays meeting .
 I use the Tfraction fitter to fit the data and get the cross section result,  the fitting is much better , but I still have some jump for the cross section , so I checked the calculation all over again and found a problem.

in the simulation  in my understanding ,the N-input for each Echannel  should be like :
cross-theory  =  Yield-mc / (const * flux * Acc )    where const is constant from target information , Acc is acceptance  =  Yield-mc / N-input  ,
so   cross-theory = Yield-mc *(N-input/Yield-mc) /(const*flux)
      cross-theory =    N-input /(const*flux)
     N-input = const*flux*cross-theory

means N-input should proportional to the cross-theory but if you check the last slides plot , the N-input number I got looks not right behavior .
Please correct me if i am wrong .
Yang , would you please also check the simulation input / flux for pi0 ? see if it is mach the theory shape ?

Cheers
Li

2016-02-11 22:18 GMT-05:00 Yang Zhang <yzhang132 at gmail.com<mailto:yzhang132 at gmail.com>>:
Dear collaborators,

We'll have our weekly meeting on February 12th, this Friday afternoon at 1:30pm in F227.

please log onto https://jlab.bluejeans.com/2265619819/ to view the sharing. And Make sure your microphone and speaker are ok before entering our meeting.

You can also dial phone number +1 888-240-2560<tel:+1%20888-240-2560> to join the meeting with meeting ID 2265619819<tel:2265619819>.

Meeting webpage:
http://wwwold.jlab.org/primex/weekly_meetings/primexII/slides_2016_02_12

Directory for your presentation files:
/group/primex/html/weekly_meetings/primexII/slides_2016_02_12
Best
Yang

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