[G12] Analysis of eta-pi photoproduction on the proton

[Michael C. Kunkel]

Greetings Andrea,

Tomorrow we will be having an non-regular meeting at out usual time.
1000 EST, 1600 CET.
We will most likely have a short meeting, so please feel free to drop in 
and make it a long meeting.
We, g12, can try to answer your questions then.

BR
MK
----------------------------------------
Michael C. Kunkel, PhD
Forschungszentrum Jülich
Nuclear Physics Institute and Juelich Center for Hadron Physics
Experimental Hadron Structure (IKP-1)
www.fz-juelich.de/ikp

On 11/13/18 7:15 PM, Andrea Celentano wrote:
> Dear g12 colleagues,
> I write you to inform that, after a long time passed after my PhD 
> thesis defense, that included a (preliminary) analysis of the gamma p 
> -> p pi0 eta reaction from CLAS-g12 data, I decided to resume this 
> analysis, starting from scratch and following closely the g12 
> procedures highlighted in the official g12 note. In the analysis, I am 
> identifying pi0 and eta via the gamma-gamma decay.
> This will be a low-priority project for me, but I’d like to come to an 
> end of it - from what I saw in the thesis, this channel is very 
> promising. Now, given the huge improvements in g12 analysis that the 
> g12 group did, I think it will be simpler to come to an end of the 
> analysis.I’d like to inform you - just to double check if there is 
> anyone else looking at this reaction.
> I have just started the analysis, and I am in the phase of selecting a 
> good sample of exclusive p pi0 eta events. Meanwhile, I also started 
> MC generation. At some point in the next future, I’d like to show some 
> progresses in one of the bi-weekly meetings, in order to get your 
> feedback from this.
>
> I already have a simple question regarding MC. I followed closely the 
> procedures highlighted in the g12 note to generate a phase-space MC 
> sample (I followed the procedures highlighted for "proton, pi+, pi-", 
> not those for "electrons and positrons"). In the real data, if I plot 
> the invariant mass of a photon pair, I see a pi0 peak at around 135 
> MeV. However, If I do the same for MC events, I see a peak at about 
> 116 MeV. I also plotted the reconstructed photon energy over the 
> generated photon energy, and I see a peak at around 0.87. It looks the 
> simulation of EC response in MC is not completely correct. (I confirm 
> that the peak for generated events is at 135 MeV)
> Is it because, using the EC, I should follow the procedure highlighted 
> for "electrons and positrons" (involving run number 10 and requiring 
> setenv CLAS_CALDB_RUNINDEX calib_user.RunIndexg12_mk?)
>
> I also have a question regarding the TOF knockout procedure. In the 
> note, the relevant method to use is: clas::g12::pass_g12_TOFKO(int 
> sector, int scid, bool all_ko = 0), that requires to know the counter 
> ID. For a charged particle, from the PART bank I can retrieve the 
> entry in the TBID bank, and from this to the SCRC bank, that, however, 
> contains information regarding TOF clusters. From this bank, I don't 
> see a pointer to the SCR bank - containing individual paddles data.
>
> Thanks,
>
> Bests,
> Andrea
>
>
>
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