[Rgc_analysis] [EXTERNAL] 8.7.0 TBT Target Polarization

[pilleux at jlab.org]

Dear Sebastian,
Please find attached the comparison between my elastic results and Greg's
inclusive analysis. They both include FCup correction and assume a beam
polarisation of 81% (I kept Greg's estimate for consistency). I think in
the past I was always getting polarisations higher than with the inclusive
analysis, this is not the case for this set of runs.

For information, these runs were cooked last Sunday. I have been analyzing
every run that has been cooked and showing my results at RGC analysis
meetings regularly, it just takes a few days sometimes. I didn't yet
include your estimator for PbPt, it's mostly implemented but I need to
make some last checks. I will work with the dilution factor later. For
these sets of runs, I get dilution factors between 80 and 90% (with the
usual method using only C data).
Best, Noémie.


> Hi Silvia,
>
> I admit I am not completely clear on which runs have been cooked “so
> far” and which ones can be trusted to be analyzed. I found Noemie’s
> most recent results at
> https://clasweb.jlab.org/wiki/images/b/b3/PbPt_elastic_RGC_Apr25.pdf
> - are there any others? In that analysis, she lists runs from two out of
> the 5 periods that Gregory analyzed. Maybe I’m missing the others, or
> Gregory used runs that haven’t been yet cooked with the newest software?
> In any case, I was hoping that Noemie (or someone else) could (re)analyze
> the runs - grouped in periods of same HWP and NMR status - that DO exist
> and that are reliable to use, with my suggested “weighted average”
> method (I believe she and Gregory agreed on this method), and perhaps even
> with the more sophisticated dilution factor calculation (again, Greg is
> using this already). Obviously just a “wish” from my side - you know
> best how to prioritize various possible tasks.
>
> From the numbers in Noemie’s link above, it appears as if “Gregory's
> 1st period” and “Gregory’s 3rd period” have elastic PbPt of 63%
> and 65%, respectively (consistent within uncertainties). Gregory’s
> analysis seems to indicate that the 3rd period actually had a somewhat
> lower polarization on average, although the evidence is not very strong.
> The absolute values seem to agree relatively nicely given that Noemie’s
> values still have Pb in them (about 0.82?). So if we would divide
> Noemie’s results by 0.82 and plot them on top of Gregory’s, we
> probably would see agreement within statistical uncertainties.
>
> Meanwhile, my request was mostly about the last 2 periods in Gregory’s
> analysis. He observed that the FC correction did not change sign in spite
> of two flips of the HWP. By comparing with elastic Pt in those 2 periods,
> I was hoping we could check (at least) that red data points (open circles)
> have a consistent trend with the elastic results. Maybe these Pt’s
> already exist - I just couldn’t find them easily.
>
> Again, I apologize if I missed or misunderstood something. I am just
> hoping someone can plot elastic data points on top of Gergory’s DIS
> ones.
>
> Thanks - Sebastian
>
> On May 3, 2023, at 3:20 AM, Silvia Niccolai
> <silvia at jlab.org<mailto:silvia at jlab.org>> wrote:
>
> Sebastian,
> Noémie has been doing elastic PbPt analysis for every set of runs we have
> cooked so far. She presented them one week ago for the latest cooked runs.
> She can directly compare her results to Gregory’s. Not sure what else
> you’re asking for.
> Best regards,
> Silvia
>
> Sent from my iPhone
>
> On 2 May 2023, at 15:20, Sebastian Kuhn via Rgc_analysis
> <rgc_analysis at jlab.org<mailto:rgc_analysis at jlab.org>> wrote:
>
>  Hi Gregory,
>
> this looks really interesting. I think it would be GREAT if someone could
> extract the ELASTIC estimate for PbPt for each of the 5 groups of runs
> that you analyzed, to see if it follows the same trend. (In principle, one
> could even use the same distinction between FC-corrected and uncorrected
> results - although that should play a lesser role for elastic asymmetries
> that are bigger).
>
> One way to address your question would be to simply look directly at the
> FC asymmetry for each of the 5 run periods. In principle, you are correct
> to expect that the FC asymmetry should be unchanged if one DOESN’T
> account for the sign change of NMR*HWP, and hence it should flip sign if
> you analyze it WITH those factors included (i.e, every time either the NMR
> or the HWP flip sign). However, it is quite possible that the FC asymmetry
> changes over time, and perhaps even right when we changed the HWP  (later
> in the run, we DELIBERATELY reset it everytime we changed the HWP, and
> Hall A may have done that already during the time you are analyzing). You
> could use your own code to calculate the FC asymmetry, or look at archived
> MYA plots.
>
> - Sebastian
>
> On May 2, 2023, at 8:51 AM, Gregory Matousek via Rgc_analysis
> <rgc_analysis at jlab.org<mailto:rgc_analysis at jlab.org>> wrote:
>
> Hi all,
>
> I realized just now that there is no meeting planned for today. I wanted
> to share my findings for the inclusive DIS Tpol calculated from the
> 8.7.0_TBT NH3 cooks.  Please see the attached image. One can see the
> progression of the extracted Tpol when changing the HWP status, and when
> changing the NMR polarization.
>
> Before I make comments about the plot, I wanted to address how I determine
> the  "direction" ofanti-parallel vs. parallel from the recent cooks. What
> I mean by this is suppose we have a single DIS event in the hipo file with
> helicity = +1. We need some mechanism to determine if this event should be
> treated as "anti-parallel" to the target spin or "parallel" to the target
> spin. It would seem that the HWP status, NMR tpol direction, and solenoid
> magnet would play a role in this. However, as far as I know, the HWP
> status is already considered at the level of cooking, so we do not need to
> use it at the analysis stage. Since the solenoid magnet direction is
> constant along the analyzed run period, I only select distinguish
> anti-parallel vs. parallel directions depending on the NMR polarization
> sign.
>
> With that being said, the Pt progression plot I included seems to show
> some consistent behavior, but I still have some questions. The run range I
> analyzed is chopped into 4 HWP sections (in, out, in, out). From the first
> in->out, the FCup correction boosts, then decrease the Tpol, which is what
> we would reasonably expect. Also, when we flip the NMR sign (closed->open
> markers) , the FCup correction goes from decreasing to boosting the Tpol.
> My concern is that when the HWP status is switched again, (out->in) the
> overall effect of the FCup corrections still boost the Tpol, opposite to
> what we saw in the first in->out transition.
>
> I apologize for the drawn out explanation, but I think we can agree that
> the FCup correction mostly consistent with what we would expect with
> changing HWP and changing Pt. Perhaps someone could brainstorm why the
> out->in transition doesn't seem to flip the impact of the FCup correction
> in comparison to the first in->out transition.
>
> Let me know if you have any questions,
> Gregory
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