[G12] Check g12 pass1 data

[Marco Ripani]

Hi Dennis, everybody,
a question and a comment/question:
1) Why did g12 decide to not write the unskimmed bos files ? Is it 
because there would be an unacceptable impact on the tape silo ?
2) It seems me it is not good to base a skim of the data on the particle 
ID. The particle ID can always be redone and results can change. Why not 
to base the skim on the number of tracks only ? It should produce a 
significant reduction in the output size already. This would allow 
making whatever skim anybody likes based on their favorite ID scheme, 
including making unbiased kinematic fits. This is particularly relevant 
for the kaons. Please keep in mind that in the future other groups in 
the collaboration may decide to analyze these data again for the same or 
different physics and there should be the minimum possible bias.

Best Regards
Marco

Dennis Weygand wrote:
> We are looking into this. The skims are based on PID, and apparently  
> SEB is finding kaons that PID is not- that is all we know right now.
> It may also be that PID is finding kaons that SEB is not- I am not  
> sure that Valery has checked for that.
> In any event, no events are lost, but if you wish to exploit the SEB  
> kaons, you may have to sum over the first five skims, which is not  
> really a big deal, but perhaps not
> as convenient as using a more exclusive skim. Certainly for quick  
> checks for enhanced kaons, the skims are fine, but may nor may not be  
> used for final event selection.
> Dennis
>
> On Aug 28, 2009, at 1:58 PM, Carlos Salgado wrote:
>
>   
>> Dear Valery
>>
>> I do not understand your statement 2.
>> It seems to me that ALL events that have a least one kaon are in  
>> skim 1.
>> Isn't this true? Some of those events could be in the other skims  
>> but if
>> you study kaons you do not need to analyze all skims, as all your
>> events are contained in 1!
>>
>> The other problem you mention is on how will we  study the  
>> efficiency of
>> the skim cuts if we do not have processed files w/o those cuts? Can  
>> we do
>> some ramdom smaple of full data or have we already study those skim
>> efficiencies?
>>
>> See you Carlos
>>
>> --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --
>> Carlos W. Salgado
>> Professor of Physics and Astronomy
>> Director, NSU Astronomical Observatory
>> Norfolk State University, Norfolk, VA23504        tel:  
>> (757)823-9212/8909
>> Jefferson Lab, Newport News, VA23606              tel: (757) 269-7859
>> fax: (757) 823-8817, e-mail:salgado at jlab.org or carlos at nsu.edu
>> http://www.jlab.org/~salgado
>> ------------------------------------------------------------------------------
>>
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>>     
>
> --
> Dennis Weygand
> weygand at jlab.org
> (757) 269-5926
>
>
>
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>   

-- 

Marco Ripani
Senior Scientist, Istituto Nazionale di Fisica Nucleare - Genova
Address:
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