[Rgc_analysis] [EXTERNAL] Re: [Rgc] RGC-analysis meeting tomorrow

[harut avagyan]

Dear All,
The difference between M_\pi\pi and M_X is the involvement of the beam
energy (also e- energy). Silvia's question triggered my attempt to check
the impact of changing the beam energy.
Before I was using 10.55 for both sets. In RCDB we have 10.547 for summer
set and 10.556 for spring. I don't know if that 10 MeV is real, but I tried
to increase beam energy, and that appeared to have a significant impact. As
you can see from
https://userweb.jlab.org/~avakian/tmp/rhocompele-inb.sqlite.10.6.pdf the
resolution significantly improved with increase of energy. That indicates
that the proper energy of the beam + account of losses on the electron side
can significantly improve the resolutions.
At this point it looks like we can go with what we have.
Best,
Harut

On Tue, Feb 18, 2025 at 12:52 PM Silvia Niccolai <silvia at jlab.org> wrote:

> Hi Sebastian,
> I agree.
> Still, I don’t understand Harut’s results. The kinematic variables of all
> particles overlap very well between summer and spring data (aside from the
> vertices), and so does the invariant mass. Why is only the missing mass
> off?
> Silvia
>
>
> Sent from my iPhone
>
> On 18 Feb 2025, at 12:25, Sebastian Kuhn <kuhn at jlab.org> wrote:
>
>  So, to me it looks like that the worsening of the Mx resolution in
> exclusive rho production is NOT related to the difference between CCDB and
> sqlite - in fact, it looks like it got even a tiny little bit WORSE with
> Harut’s most recent plots (CCDB) - counter to the other (elastic and pDVCS)
> results. In any case, this should have no bearing on the review tomorrow -
> there are many things one can check to hopefully improve that resolution
> for Winter/Spring ’23 - including a careful accounting for the target
> position (which appears to be different), checking all cuts and background
> subtractions, etc. (BTW, I’m afraid we really need to check all vertex
> distributions for EVERY EPOCH, where an epoch refers to a set of runs
> during which no manipulations on the target occurred - including material
> changes, motion, repairs etc.)
>
> This leaves us with the SLIGHT remaining difference between CCDB and
> sqlite for some of the elastic and DVCS distributions. We should
> triple-check that these are really labeled correctly, since it is
> surprising why a small IMPROVEMENT in vertex resolution (which is what
> Derek’s plots show) could result in a worse resolution in phi etc. In fact,
> here is a theorem: To first order, Delta-phi between the electron and the
> proton in a truly elastic event DOES NOT DEPEND ON THE VERTEX AT ALL!
> Again, we may have to check cuts, analysis procedures etc. to understand
> this small difference, but the way we should present this to the committee
> is by saying that either version would be fine to use, and unless we are
> convinced that sqlite actually improves the resolution, we’ll stick with
> CCDB. (This should be clarified in the time frame that usually expires
> anyway between the presentation and the final response to all requests from
> the committee. It certainly should not require a repeat of the review nor
> hold up the green light for cooking).
>
> - Sebastian
>
> On Feb 18, 2025, at 11:29, harut avagyan via Rgc_analysis <
> rgc_analysis at jlab.org> wrote:
>
> Hi Silvia,
> I somehow managed to create some ntuples. I will continue checking their
> integrity, but what I got, doesn't support my hope that with the rcdb
> version the resolution of the rho missing mass peak will improve. The plots
> are in https://userweb.jlab.org/~avakian/tmp/rhocompele-inb.rcdb.pdf
> They include now also all kinds of vertex (x,y,z) distributions for
> e-,\pi+ and pi- and they all seem to be shifted. One can check if they are
> consistent with what we expect.
> BEst,
> Harut
>
> On Tue, Feb 18, 2025 at 10:50 AM harut avagyan <avagyan.harut at gmail.com>
> wrote:
>
>> Dear All,
>> One strange thing, I guess also others observed, is the shift of the
>> target center along z. That is confirmed by z-vertex comparison of the
>> electrons in exclusive rho (see
>> https://userweb.jlab.org/~avakian/tmp/RGC-e-vertex.pdf).  If  the  shift
>> of ~2cm (inbending only compared)  is real, the loss of high energy
>> electrons in inbending in old configuration compared to new one is hard to
>> link to it.
>> Could target people confirm that possibility?
>> Thanks,
>> Harut
>>
>> On Mon, Feb 17, 2025 at 4:33 PM silvia via Rgc <rgc at jlab.org> wrote:
>>
>>> Dear all,
>>> we'll have our RGC-analysis meeting tomorrow, Tuesday, at 8:30AM JLab
>>> time, zoom link: https://urldefense.proofpoint.com/v2/url?u=https-3A__jlab-2Dorg.zoomgov.com_j_1609368114&d=DwIFaQ&c=CJqEzB1piLOyyvZjb8YUQw&r=aSEBncnFTdfouxOejKajYG--Ygz0DFQolIcHUhF20pw&m=Qmri8ggVaznaaFw_F-ECGPUFkBkvIRW6Msi5xcCxKvHQ-w72izsTpKQAllTmSjCV&s=3VLHUv1mbq2zq6C8ivF7BmsEQBXs_nKXzLfiyRdNEMs&e= 
>>> <https://urldefense.proofpoint.com/v2/url?u=https-3A__jlab-2Dorg.zoomgov.com_j_1609368114&d=DwMFaQ&c=CJqEzB1piLOyyvZjb8YUQw&r=aSEBncnFTdfouxOejKajYG--Ygz0DFQolIcHUhF20pw&m=eOQtJErmkjqJOoGl4Dsu4IQFuYKWAm3aaZQasTu6pVRmyK1eRx_i5n3I3W-2pnm9&s=yo7hTiwe_hi5tOGeI4yW60EGUfyXFTAl-zIKVbDedfQ&e=>
>>> , wiki page:
>>> https://clasweb.jlab.org/wiki/index.php/RGC_Feb18
>>> Please let me know if you plan to present something.
>>> Best regards,
>>> Silvia
>>> _______________________________________________
>>> Rgc mailing list
>>> Rgc at jlab.org
>>> https://mailman.jlab.org/mailman/listinfo/rgc
>>>
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