[G12] MC TOF Resolution

Michael C. Kunkel mkunkel at jlab.org
Thu Jul 18 13:39:30 EDT 2013


Hi Lei,

The blue is MC and red is data.
Yes the data is wider than the MC but normal timing cut is 2ns, which is 
well in bounds for both sets of data.

I use the same flags Mukesh derived for gpp and the same flags located 
on the G12 MC page for gamp2part.

BR
MK
On 7/18/13 1:41 PM, Lei Guo wrote:
> HI, MK,
>
> Is blue the simulation? In that case, your looks like what is expected 
> from MC data. What are the flags you used in your simulation steps?
>
> On the other hand, it seems that the data is wider than simulation, so 
> the same cut in timing for MC as that used in MC would overestimate 
> the acceptance, and probably lead to a systematic lowering of the 
> cross sections.
>
> Lei
> On Jul 18, 2013, at 9:26 AM, Michael C. Kunkel wrote:
>
>> Maybe I should be a little more specific for the group.
>>
>> I looked at the lepton timing last night. I have attached the plots I 
>> sent to Jason. I see nothing wrong with the MC timing or maybe I do 
>> not understand his problem correctly.
>>
>> On the attached plots, red represents the actual G12 data and black 
>> is a simulation. The title of the plots tell you the species of 
>> lepton(electron(Em)/positron(Ep)). The quantity plotted is Tpho + 
>> tprop - scvertextime, where scvertextime = sc_time - 
>> scPathLen/(LIGHT_SPEED * beta)
>>
>> BR
>> MK
>>
>> On 7/18/13 9:18 AM, Michael Kunkel wrote:
>>> What was wrong with the plots I sent you before you sent this email?
>>>
>>> BR
>>> MK
>>>
>>> Sent from my iPhone
>>>
>>> On Jul 18, 2013, at 8:17, Jason Bono <jbono at jlab.org> wrote:
>>>
>>>> Hello all, since mukesh did his MC TOF study we have been using the 
>>>> gpp flags he determined which are found both on the wiki and in the 
>>>> g12 Analysis Procedures, Statistics and Systematics note.   The 
>>>> wiki shows that the gpp flags:
>>>>
>>>> -a=2.73 -b=1.7 -c=1.93 -f=1
>>>>
>>>>
>>>> which gives SHOULD give a timing resolution of about 0.2 ns as 
>>>> shown in Mukesh's plot:
>>>>
>>>> <Screen Shot 2013-07-17 at 10.54.18 AM.png>
>>>>
>>>> When I generate events as outlined by Mukesh or in the g12 note i 
>>>> get a resolution two times a wide and is not really gaussian.  As 
>>>> of now I suspect the problem is coming from gamp2part but i haven't 
>>>> yet confirmed.  I would like to find the problem so that the g12 
>>>> analysis procedures note can be updated and accurate.
>>>>
>>>>
>>>>   Ive spoken with a few people who said that they get this same 
>>>> resolution but have not seen a plot like above.  Since Mukesh is 
>>>> now gone can someone who has been producing MC with this resolution 
>>>> make the able plot and show it in today's or next weeks g12 meeting 
>>>> along with exactly how they generated the events?  i.e. something 
>>>> like:
>>>>
>>>>
>>>> genr8 -BLLL,UUU -MNNN -owork.gamp L0 -U10 < genr8input_XXX.VVV
>>>> gamp2part -r10 -owork.part -T -S-0.321,0.378,-0.254,0.407 
>>>> -z-110,-70 work.gamp
>>>> gsim_bat -ffread ffread.g12 -kine 1 -mcin work.part -bosout 
>>>> work.gsim -trig 2000000
>>>> gpp -Y -s -a2.73 -b1.7 -c1.93 -f1 -R10 -P0x7f -owork.gsim.gpp 
>>>> work.gsim
>>>> a1c -T4 -sa -ct1930 -cm0 -cp0 -X0 -d1 -F -P0x1bff -z0,0,-90 
>>>> -Aprlink_tg-90pm30.bos -owork.gsim.gpp.a1c work.gsim.gpp
>>>>
>>>>
>>>> Which is my current template I use for generation.
>>>>
>>>> Thanks,
>>>> Jason
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>>
>> <Em_timingcompare.png><Ep_timingcompare.png>_______________________________________________ 
>>
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