[G12] vertex distribution

[Dennis Weygand]

OK, I think I got it:

Your e+ e- gamma sample has a large number of events such that:

1) pi0 --> gamma gamma
2) One of the gamma's converts in material outside of the target

MVRT still has the correct vertex since the e+ e- opening angle is 0.

Dennis




On Mar 18, 2013, at 3:52 PM, Michael C. Kunkel wrote:

> Greetings, 
> 
> I got my hands on PPipPim data to plot the MVRT information. 
> I have posted the plots of the r of MVRT and x vs. y of MVRT for the following topologies: 
> 
> Pion; Missing Mass Proton Pi+ Pi- -> 0 (exclusive) 
>          Effective Mass Pi+ Pi- ->Omega 
> 
> Lepton: Missing Mass Proton e+ e-  < Pi0 
>              Missing Mass Proton e+ e- gamma -> 0 (exclusive) 
>              Effective Mass e+ e- gamma ->Pi0 
> 
> Plot can be found at
> https://clasweb.jlab.org/rungroups/g7/wiki/index.php/Reconstruction_study
> for March 18, 2013
> 
> Before anyone cries "bug", let me assure everyone that the manner in which the MVRT data is collected for the pions is the same as for leptons, i.e. a clasEvent function. 
> 
> From what I deduce, it appears that either exclusive Pi0 production can happen outside of the target (cough cough), or for some reason when the particle is a lepton, we have resolution problems. Neither I can understand from looking at what creates the MVRT. 
> 
> Thoughts and help would be appreciated greatly. 
> 
> BR 
> MK 
> 
> 
> On 3/13/13 3:46 PM, Dennis Weygand wrote:
>> Does anyone have  plots of vertex distributions (z, x vs y, r from MVRT) for any topology?
>> Dennis
>> 
>> --
>> Dennis Weygand
>> weygand at jlab.org
>> (757) 269-5926 (office)
>> (757) 870-4844 (cell)
>> 
>> 
>> 
>> 
>> 
>> 
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> 

--
Dennis Weygand
weygand at jlab.org
(757) 269-5926 (office)
(757) 870-4844 (cell)




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