[Primex2] Compton result from Li

Mon Feb 15 20:08:18 EST 2016

 Hi Li and Liping,

Thanks for the answers.
I think I found the origin of this pattern:
the flux which was used in MC is slightly different
from what we have for Compton data sample after all: MC flux was done before
finalizing Compton flux. It should not affect the efficiency
since relative difference in mean energy for all bin groups
is less or equal ~10^-4 (old vs new flux). In principle
we can regenerate but I think it's not worth - 10^-4 level is enough.
The question is why c.s. on page 17 is repeating used MC flux?,
it may indicate some issues in extraction process.

 Ilya

----- Original Message -----
From: "li ye" <yeli.ciae at gmail.com>
To: "ganl" <ganl at uncw.edu>
Cc: "Ilya Larin" <ilarin at jlab.org>, "pawel" <pawel at jlab.org>, "primex2" <primex2 at jlab.org>
Sent: Monday, February 15, 2016 5:22:47 PM
Subject: Re: Compton result from Li

Hi Ilia,
regarding your questions:
1) the vertical axis is  the input events number / data flux* 10e9
2) 10 combined Echannel is one energy bin  first bin (4.4Gev) is for
Echannel 170- 180
3)  MC input is the generated events number which put in the simulation for
each Echannel , not reconstructed number
4) I will show you more plot later
5) flux means data flux

Cheers

2016-02-16 6:11 GMT+08:00 Gan, Liping <ganl at uncw.edu>:

> Hi, Li,
>
> Would you please answer Ilya's questions?
>
> Liping
>
> -----Original Message-----
> From: Ilia Larin [mailto:ilarin at jlab.org]
> Sent: Monday, February 15, 2016 4:04 PM
> To: Gan, Liping
> Cc: li ye; pawel; primex2
> Subject: Re: Compton result from Li
>
>
> I Liping,
> I thing I need to clarify some details about page 17 bottom plot, so I can
> look at MC:
>
> 1) what are the units on vertical axis?
> 2) what is exact energy bin definition?
> 3) "the Monte Carlo event number" means  generated or reconstructed number?
> 4) if he checked the photon flux distribution - why not show it as well on
> the presentation
> 5) flux in denominator means data flux, not mc flux
>
> Ilya
>
>
>
> ----- Исходное сообщение -----
> От: "ganl" <ganl at uncw.edu>
> Кому: "Ilya Larin" <ilarin at jlab.org>
> Копия: "li ye" <yeli.ciae at gmail.com>, "pawel" <pawel at jlab.org>, "primex2"
> <primex2 at jlab.org>
> Отправленные: Понедельник, 15 Февраль 2016 г 15:28:59
> Тема: RE: Compton result from Li
>
> 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
>
> _______________________________________________
> Primex2 mailing list
> Primex2 at jlab.org<mailto:Primex2 at jlab.org>
> https://mailman.jlab.org/mailman/listinfo/primex2
>