[G14_run] [EXTERNAL] G14 meeting today at 9:00 - Bluejeans link

[Igor Strakovsky]

Dear All,

Please find attached GRAAL paper for gn-->pi-p Sigma measurements.  Then
please find attached G13 data from Daria (rivesd vs her PhD Thesis) - they
are still unpublished and GRAAL measurements. These data are in the SAID DB.

I spent a lot of time trying to understand what is going on here...

Then please find attached Giuseppe's plot with some explanation of his
analysis.  There is a transition range between two detectors (25 deg in lab
for protons or 120 deg in CM for pi-).

I splitted GRAAL angular distributions in two two parts below and above 120
deg.  Then fit selected the best norm factor for each.

My rather old evaluation gave the following: Please look over the attached
plot...
There are not so many energy bins to compare GRAAL with G13 and I found 8
samples:
Blue filled circles are your data
Red open circles are GRAAL measurements
Black filled triangles are previous measurements (Yerevan and so on).
Blue solid lines show recent SAID MA27 (Paul's paper).

BTW, Daria has two different settings.  She called them F1 and F2.  Sorry,
I do not remember what that is.

And one more important thing...
It is impossible to measure FSI experimentally, it requires calculations...
As  our group reported in several CLAS and A2 papers, the FSI corrections
are about 15% above pion production angle 30% (it is flat).  For the
forward direction they grow dramatically (up to 60-70%) but there are no
forward measurements.  There are no calculations of FSI for any polarized
measurements and our assumption is that FSI corrections in this case are
small
or consistent with uncertainties.  The indirect proof of this assumption is
that we can fit G13 data vs the world DB perfectly.

My 2c,
Igor

-----
Igor Strakovsky, SAID INS The George Washington University
Tel: 571-553-8344(VC),202-994-4742(FB),Skype: igors1945_2,
Cell: 703-728-5627,Emails: igor at gwu.edu, igor at jlab.org


On Thu, Aug 19, 2021 at 8:26 AM Annalisa D'Angelo <
annalisa.dangelo at roma2.infn.it> wrote:

> Dear All,
>
>
> This is a reminder of today’s g14 meeting at 9:00 Jlab time.
>
> The bluejeans link is:
>
> Meeting URL
> https://urldefense.proofpoint.com/v2/url?u=https-3A__bluejeans.com_593356414&d=DwIFaQ&c=CJqEzB1piLOyyvZjb8YUQw&r=5LSWsFN5KweowPCsdwCuTw&m=uajDRipUJlgq_cWnmV7LXK4PtiCJIoMIE_jMYs_yMNY&s=i2o67zKj295kt0PfToDIQCPVF4GJ3K09SBXfIcgKv_Q&e= 
> <https://urldefense.proofpoint.com/v2/url?u=https-3A__bluejeans.com_593356414&d=DwMFaQ&c=CJqEzB1piLOyyvZjb8YUQw&r=5LSWsFN5KweowPCsdwCuTw&m=SG8K6GVy_nt8BQXdzZ48zv5BKvGmUoyvDAk8qZlW1mA&s=fCzmqX2xjveiXyC3mLTUMFGRRLDFrHeriGNiDAGX-EA&e=>
>
>
> Meeting ID
> 593 356 414
>
> Franz has kindly agreed to chair the meeting
>
> All the best
>
> Annalisa
>
> Prof.ssa Annalisa D'Angelo
> Dip Fisica Università di Roma Tor Vergata e INFN Roma Tor Vergata
> Jefferson Lab
>
> _______________________________________________
> G14_run mailing list
> G14_run at jlab.org
> https://mailman.jlab.org/mailman/listinfo/g14_run
>
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