[G14_run] Questions about K0 Lambda channel.

[Eugene Pasyuk]

Trigger configuration information is entered into the run database at 
the beginning of every run. You can always find it there.
To your GPID question. The is variable 'tagrid' which is a pointer to 
the tagger hit which was matched to this particle or 0 if no matching 
photon was found. To check if particles matched to the same photon you 
need to check that tagrid is the same for those particles. One more 
variable to look at is ngrf. It is 0 if no matching photon was found, 1 
if photon was found and could be >1 if there are more than 1 photon is 
in this beam bucket.
there is more details in CLAS note 2007-008.

-Eugene


On 2/16/12 12:07 , Paul Mattione wrote:
> 68050 used a single-sector trigger.  The trigger was changed to a two-sector trigger between runs 68197 and 68198.  We are now running with a 2 sector trigger and 1-sector pre-scaled, but I'm not sure what run that switch was made.  Try using runs after 68197.
>
> I don't know anything about rootbeer or GPID to help you there.
>
>   - Paul
>
> On Feb 14, 2012, at 11:22 PM, Dao Ho wrote:
>
>> Dear all,
>>
>> I just finished a short study of the K0 Lambda channel using the rootbeer
>> package.
>> I processed about 3.6 million events of the run 68050.
>>
>> Out of that 3.6 millions, I got for
>> mostly are 2 or 3-track events.
>> 5-track events : the number of events is 4 events.
>> 4-track events: the number of events is 130 events--->only 13 events were
>> identified as 2 pi-, 1 pi+, and 1 proton. I used the GPID bank.
>>
>>
>> Were these number expected? They seem small to me?
>> Is it because of the nature of the run 68050 (one or two -particle
>> triggered?)?
>> How to use the GPID information to check whether the same photon was used
>> for each particle?
>>
>> Let me know your opinion.
>> Sincerely,
>> Dao Ho
>>
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