[Genrp] [Sbs_gems] [EXTERNAL] Re: GEn-RP/KLL slides

[Michael Kohl]

Dear David,

thanks for the Dubna reference. I am attaching the PDF.

Regarding Bogdan's question on the FOM ratio of FOM-PR/FOM-CE = 2.6/0.8 
from slide 13:

The Basilev paper has all your simulations for "Polarimeter A" (charge 
exchange with forward proton tracked and in HCAL) and for "Polarimeter B" 
(elastic with active analyzer and forward neutron in HCAL), and the plot 
for FOM looks identical to what we have been showing many times, and to 
the plot on slide 11.

The Dubna neutron beam had a momentum of 3.75 GeV/c.
For E12-17-004, the neutron momentum is 3.15 GeV/c for Q2=4.5.

At 3.15 GeV/c, the FOMs of both np->pn charge exchange and np->np elastic 
look within 20-30% the same (i.e. close to where the crossover is), and 
the CHX FOM only gets better at the higher Dubna momenum of 3.75 GeV/c.


Can you comment on that? Is it all (the lower np->np elastiv FOM) 
explained with the active analyzer solid angle covering only a fraction of 
the neutron solid angle?


Second, from skimming the Dubna paper, it is not immediately evident to me 
that the result of the Dubna measurement of Ay for neutron on Cu charge 
exchange is actually consistent with the FOM simulation and the assumption 
that went into your simulation. The Ay values on slide 10 for charge 
exchange are at the level of Ay ~= -0.4 to -0.3 (also Fig 4 in Basilev). 
You mentioned that 50% of Ay was used for the FOM simulation. However the 
Dubna results for Ay seem to be at a level of Ay ~= 0.05.

Could you comment on that, too?


Please kick me if I missed something or if I am confused.

Thanks,
   Michael




On Tue, 16 Jan 2024, Bogdan Wojtsekhowski wrote:

> Hi Michael,
> 
> Here are a few comments on your slides:
> Slide 1:The list of GEn-RP spokespeople, need to add John Annand, Enzo
> Bellini and Nikolay Piskunov with * - retired.
> Slide 3: Accurate LT separation for GEn is under way in nTPE, two-photon
> exchange is a complication for GE/GM extraction
> Slide 5: Dipole rotates (mostly) Pl but just very little Pn
> Slide 6: Motivated by prediction of large effect from twist-3 by P. Kroll
> Slide 7: The large angle recoil proton is NOT Conventional
> Slide 12: g4sbs - add a reference to A. Puckett; Is precession already
> added?
> Slide 13: ratio FOM-PR/FOM-CE = 2.6/0.8 ? What is a fraction of the detector
> area 
> includes the active analyzer?
> Slide 18: Looks Glasgow second student is missing; JLab group is missing;
> SBS contributors need to added for example: UConn, W&M
> Best regards,
> 
> Bogdan
> 
> ____________________________________________________________________________
> From: Sbs_gems <sbs_gems-bounces at jlab.org> on behalf of William Tireman via
> Sbs_gems <sbs_gems at jlab.org>
> Sent: Tuesday, January 16, 2024 6:49 AM
> To: Michael Kohl <kohlm at jlab.org>
> Cc: David Hamilton <David.J.Hamilton at glasgow.ac.uk>; Sbs_gems
> <sbs_gems at jlab.org>; genrp at jlab.org <genrp at jlab.org>; Saru Dhital
> <dhitalsaru616 at gmail.com>
> Subject: [Sbs_gems] [EXTERNAL] Re: GEn-RP/KLL slides  
> Good morning,
> 
>  My lab runs from 12 to 2:50 PM and is in a room 10 feet from my office so I
> do not need much time to transition. I will stay as long as I can.  I am
> available after 3 PM but that is getting pretty late for Glasgow time.
> 
> Sincerely,
> Will
> 
> On Tue, Jan 16, 2024 at 12:36?AM Michael Kohl <kohlm at jlab.org> wrote:
>       Dear David, Will, Holly, all,
> time keeps pressing ?
> 
> here are finally some draft slides for the 15-minute presentation on
> GEn-RP and KLL on Wednesday at 10:50am.
> (Thanks Saru for some recent materials; everything else is taken from
> various Wikis).
> 
> We (David, Will, ?)agreed to hold a Zoom meeting at 11:30am tomorrow
> (i.e., today) Tuesday to go over this.
> Let?s use this link: https://jlab-org.zoomgov.com/j/1612414919
> (This will be after the Hall-A business meeting and during Martha's
> GPD talk, unfortunately there is no other way since Will can?t meet
> after 12 if I remember it correctly).
> 
> Will: If you still have some availability in the afternoon as well,
> please let me know.
> David: Do you have any updated figures, e.g. FOM, projected errors, or
> a slide of the Dubna Ay measurement?
> Holly: Do you feel that more detail is needed for the timeline? Are
> there any items not on hand that are needed for GEn-RP and KLL?
> Non-GEM activities: Is there an installation and commissioning plan,
> and has there been any coordination with GEM installation activities?
> Anyone: if there is anything else you wish to be reported here, please
> provide/let me know/come to the 11:30 meeting.
> 
> Thanks and best regards
>   Michael
> 
> 
> 
>

+---------------------------------------------------------------------
Dr. Michael Kohl, Professor and Staff Research Scientist
Physics Department, Hampton University, Hampton, VA 23668
Jefferson Lab, C117, 12000 Jefferson Avenue, Newport News, VA 23606
Phone: +1-757-727-5153 (HU office), +1-757-256-5122 (Cell)
Email: kohlm at jlab.org
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