[Primex2] Compton result from Li

Mon Feb 15 20:21:48 EST 2016

Hi Li,

I think I don't completely understand what means
"acceptance = input number / yield",
and acceptance function on the plot does not necessarily
look wrong - depends on stat. errors.

 Ilya

ps: yes, sure we can discuss tomorrow.

----- 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 8:08:53 PM
Subject: Re: Compton result from Li

Hi Ilia,

here I attached flux plot and MCinput plot , they looks like same shape
that's why I assume the MC input number should proportional to the flux,
of course the final cross section has nothing to do with this input, only
depend on the acceptance and the yield .
if you make the input number has some random variation , that also
make sense, I just want to make sure what you did in the simulation.
but either way , I must have the smooth acceptance right ?
I plot the acceptance , which = input number / yield ,   here the yield is
what I got from reconstructed simulation result , without any cut .
but the acceptance still look not right .
may be we can talk more face to face .  are you available tomorrow ?
Thanks
Li

2016-02-15 17:22 GMT-05:00 li ye <yeli.ciae at gmail.com>:

> 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
>>
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