[Clas_cascades] Meeting notes July 22

[Zhiwen Zhao]

Hi,Hovanes

Here is my understanding.
1. acceptance reduction due to decay vertex location is 30%
2. acceptance reduction due to raw ST hit requirement is 15%
3. data yield reduction due to decay vertex location is 17%
4. data yield has trigger inefficiency already, no further reduction.

I just wonder how to combine 1 and 2 to form correct final acceptance, because I 
feel their conditions have some overlap, but not the same, they are equal only 
when those raw ST hit are from Lambda decay particles.
Should the exact condition matching the experiment be checked?
I suppose it's like "most than 3 tracks have SCPB and ST hit and Lambda decay 
not beyond ST"

Zhiwen



On 7/23/2010 6:18 PM, Hovanes Egiyan wrote:
> Hi Zhiwen,
>
> with the decay vertex analysis the correction trigger inefficiency was ~18%. The
> acceptance reduction after the reconstructed vertex cuts was ~30%. But these cuts
> affect the real data as well. These vertex cuts reduced the data sample by ~17%.
> So, 0.83/0.70=0.18 .
>
> For the study with the cuts on the raw ST hits the cuts in the data are not
> necessary since it happens on the trigger level. The ratio of the acceptances
> gives the estimate of the triggering inefficiency, and it came out ~15%.
>
> Hovanes.
>
>
> On 07/23/2010 03:45 PM, Zhiwen Zhao wrote:
>> Hi, Hovanes
>>
>> Sorry I missed the meeting.
>> So if you look the raw ST hit, you have correction 15% and if you look the decay
>> location, you have correction 30%, are you gonna use both for final
>> corrections? Don't those two conditions have some overlap?
>>
>> Zhiwen
>>
>> On 7/23/2010 10:52 AM, Hovanes Egiyan wrote:
>>> Present: Hovanes, Stepan, Kijun
>>>
>>> Notes by Hovanes.
>>>
>>>
>>> * Hovanes made an update on his estimates of trigger inefficiency due to the
>>> decay outside of the start counters
>>> <http://clasweb.jlab.org/rungroups/eg3/wiki/index.php/Trigger_efficiency_loss_estimates_due_to_detached_vertices_outside_ST_by_using_cuts_on_STN0_banks_in_the_acceptance_calculations>.
>>>
>>> This time he calculated the acceptance with cuts on raw ST hits.
>>>
>>> * His studies show that ~15% of the MC events will not produce ST hits in
>>> three sectors to fire the bit 6 of the eg6 trigger. He also assigns 5%
>>> uncertainty to this estimate.
>>>
>>> * Hovanes updated the response document and checked it in into CVS. He will
>>> add a subsection into the analysis note and post it for the group to
>>> review before sending it to the committee.
>>>
>>>
>>>
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