Oops, I was looking on file "readout20140108", since I assumed that all
files in: "/mss/hallb/hps/production/readout/tritrig-beam-tri/2pt2/" are
the same. Shame on me!
I take my words back, and I am copying the files from "readout20140522"
series.
Sorry,
Mikhail.
On 10/14/2014 06:34 PM, Graham, Mathew Thomas wrote:
>
>>
>>
>> On Tue, 14 Oct 2014,[log in to unmask]
>> <mailto:[log in to unmask]>wrote:
>>
>>> Hi Matt,
>>>
>>> and others responsible for generated/simulated data, I have a question:
>>>
>>> I took your data from:
>>>
>>> /mss/hallb/hps/production/readout/tritrig-beam-tri/2pt2/
>>>
>>>
>>> tritrigv1-egsv3-triv2-g4v1_s2d6-readout20140522_[1-10000].slcio
>>>
>>>
>>> and from description I thought this was a right mix of trident data
>>> and beam background. However, I found some difficulty interpreting
>>> these files:
>>>
>>> 1. there is no distinction between "signal" (trident) and
>>> background, if you select events produced at t=0 and having no
>>> parents they are still not distinguishable completely (usually >3
>>> particles/event);
>>
>> For tridents, the signal particles should share a parent, and the
>> parent should have PDG ID 622. There should be exactly one such
>> trident in every event in the files you're looking at.
>>
>> There may be other tridents ("background tridents") in the event,
>> which will not be labeled in this way; if they occur in the same beam
>> bunch as the signal trident, they can be identified in the way you
>> describe.
>
>
> Looking at this file, I do see the 622 parent & daughters...
> tritrigv1-egsv3-triv2-g4v1_s2d6-readout20140522-recon20140614_1.slcio
>
> Here is a printout
> =========================================================
> …lots of brems & conversions…
> MCP PDG ID = 11; time = 0.0
> Parent = 622
> Daughter = 11
> MCP PDG ID = -11; time = 0.0
> Parent = 622
> MCP PDG ID = 22; time = 0.704967737197876
> Parent = 11
> MCP PDG ID = 11; time = 0.0
> Parent = 622
> Daughter = 22
> MCP PDG ID = 622; time = 0.0
> Daughter = 11
>
>
> =========================================================
>
>
> …and here’s the snippet used to create it…
>
> List<MCParticle> mcpList=event.get(MCParticle.class,"MCParticle");
> for(MCParticle mcp: mcpList){
> System.out.println("MCP PDG ID = "+mcp.getPDGID()+"; time
> = "+mcp.getProductionTime());
> if(mcp.getParents().size()>0)
> System.out.println( "\t\tParent =
> "+mcp.getParents().get(0).getPDGID());
> if(mcp.getDaughters().size()>0)
> System.out.println( "\t\t\t\t Daughter =
> "+mcp.getDaughters().get(0).getPDGID());
> }
>
>>
>>>
>>> 2. even if you find a combination of 3 particles with close missing
>>> mass it is >10^-2 GeV (varying), while I expected <10^-4 GeV^2 (fixed).
>>
>> Since tridents are produced at random Z within the target, they are
>> affected by multiple scattering. Since we don't use SLIC to simulate
>> target interactions, the MS is applied outside of SLIC, and so the
>> particles listed in SLIC have already been smeared by MS.
>>
>> Matt should confirm that the mass you're seeing is consistent with
>> this explanation.
>
> Not sure why this is…
>
>>
>>>
>>> Any suggestion?
>>>
>>> Best Regards,
>>> Mikhail.
>>>
>>>
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