[Clas12_rgh] [EXTERNAL] RGH Jeopardy document

Christopher Keith ckeith at jlab.org
Mon Apr 8 10:13:50 EDT 2024 

Hi everyone,
I just updated the Figure-of-Merit section of the jeopardy document, comparing NH3 with the PAC39-approved version of HD.  According to their report, the requirement was a "...spin relaxation time of 50 days with a beam current of 1 nA."  So I used those numbers to generate the table.  Please take a look and let me know if it does not make sense.

Thanks,
Chris
________________________________
From: Clas12_rgh <clas12_rgh-bounces at jlab.org> on behalf of Volker Burkert via Clas12_rgh <clas12_rgh at jlab.org>
Sent: Sunday, April 7, 2024 10:41 AM
To: silvia at jlab.org <silvia at jlab.org>; Anselm Vossen, Ph.D. <anselm.vossen at duke.edu>
Cc: clas12_rgh at jlab.org <clas12_rgh at jlab.org>
Subject: Re: [Clas12_rgh] [EXTERNAL] RGH Jeopardy document

Hi Anselm,

My understanding is that the number  Sylvia came up with is a process-independent evaluation. However, if you want to measure polarized target asymmetries you will have to take into account that of the 17 nucleons in NH3 only the 3 protons in the hydrogen are polarized. Then it depends how well you can separate the process you are interested from the background contributions, what the effective luminosity is. For SIDIS, if you are able to identify that the reaction occured on a proton, the reduction is 3/10. If you cannot separate reactions on free (polarized) protons from bound (unpolarized) protons  (which may be possible at some level for an exclusive process like DVCS, but may be difficult in SIDIS), you would have to make a subtraction of measurements on an unpolarized target, e.g. carbon-12, from the NH3 data, which will also significantly affect the sensitivity.
Of course, RG-C had to deal with the same subtraction procedure it would be best to get input from the RG-C folks (Sebastian, Harut,Sylvia,...).

In any case, the detector luminosity is the number ~5x10^33 (unless we find some improved shielding for the background; this should be explored further), but the effective luminosity, which determines the sensitivity of your reaction, is significantly reduced from the unpolarized part of the target, and is process dependent.

Cheers,
Volker


________________________________
From: silvia at jlab.org <silvia at jlab.org>
Sent: Sunday, April 7, 2024 5:34 AM
To: Anselm Vossen, Ph.D. <anselm.vossen at duke.edu>
Cc: Volker Burkert <burkert at jlab.org>; clas12_rgh at jlab.org <clas12_rgh at jlab.org>
Subject: Re: [Clas12_rgh] [EXTERNAL] RGH Jeopardy document

Hi Anselm,
in our DVCS count-rate estimate we are taking RGA Fall18 data for pDVCS
and rescaling them by a RGH/RGA acceptance ratio (from gemc simulations of
the two run periods), times a ratio of the luminosities and beam times of
the two RGs. For RGH we have used 5*10^33 lumi and 100 days of beam time.
For RGA we have been having a hard time getting feedback from various RGA
members on how many PAC days Fall18 corresponds to. We were finally given
the integrated charge. Assuming a luminosity of 0.8*10^35 for RGA, we
deduced roughly 10 days of beam time for the inbending dataset.
So the lumi factor RGH/RGA comes out to be 100/10*(5*10^33/0.8*10^35)=0.6.
Then you need to fold in the acceptance ratio, which depends on your
reaction.
Best regards,
Silvia


> Dear All,
>
> Matthew worked on SIDIS simulations that he will show Monday.
> He will look at single and di-hadron asymmetries.
> I talked to Andreas Metz from Temple who I work with on EIC impact studies
> and he told me that they can try to come up with impact studies using RGH
> pseudodata in the next two weeks (but no promises).
>
> I also promised Marco to work on the SIDIS part in the next few days.
>
> One question though about the anticipated statistics: I see the dilution
> and polarization factors for the target in the document but it is not
> clear to me how the anticipated integrated luminosity compares to a given
> RGA period.
>
> From the conservative luminosity estimate, I would get a factor 20 less
> but how much running time is requested? Is 1/20th of the RGA statistics
> reasonable?
>
> What are the DVCS projections using?
>
> Thanks,
>
> Anselm
>
>
>
> ________________________________________
> From: Clas12_rgh <clas12_rgh-bounces at jlab.org> on behalf of Silvia
> Niccolai via Clas12_rgh <clas12_rgh at jlab.org>
> Sent: Saturday, April 6, 2024 12:40 PM
> To: Volker Burkert
> Cc: clas12_rgh at jlab.org
> Subject: Re: [Clas12_rgh] [EXTERNAL] RGH Jeopardy document
>
> Hello all,
> Sebastian, Adam and I are working on DVCS projections, I’ll include them
> tomorrow and update the text accordingly.
> Best regards,
> Silvia
> Sent from my iPhone
>
> On 6 Apr 2024, at 18:25, Volker Burkert via Clas12_rgh
> <clas12_rgh at jlab.org> wrote:
>
> 
> Thank you Chris!
>       Much improved on the polarized target.
> Volker
>
> ________________________________
> From: Christopher Keith <ckeith at jlab.org>
> Sent: Saturday, April 6, 2024 9:10 AM
> To: clas12_rgh at jlab.org <clas12_rgh at jlab.org>; mcontalb at fe.infn.it
> <mcontalb at fe.infn.it>; Volker Burkert <burkert at jlab.org>
> Subject: Re: [Clas12_rgh] [EXTERNAL] RGH Jeopardy document
>
> Hi Volker,
> Take a look at the jeopardy document again.  I did some editing yesterday
> afternoon.  There is a new, longer Target section, and references to the
> bulk superconducting magnet and Hall C magnet have been commented out.
>
> Chris
> ________________________________
> From: Clas12_rgh <clas12_rgh-bounces at jlab.org> on behalf of Volker Burkert
> via Clas12_rgh <clas12_rgh at jlab.org>
> Sent: Friday, April 5, 2024 10:27 PM
> To: clas12_rgh at jlab.org <clas12_rgh at jlab.org>; mcontalb at fe.infn.it
> <mcontalb at fe.infn.it>
> Subject: Re: [Clas12_rgh] [EXTERNAL] RGH Jeopardy document
>
> Dear Marco,
>
> I have read the draft and have a few comments that I list here.
>
>
>   1.
> In section 2  Physics highlights under GPD E it says that "Its measurement
> in ... DVCS  requires a transversely polarized proton target as a
> complementary approach to the beam spin asymmetry of an unpolarized
> neutron target"  I think this formulation is misleading as it could be
> interpreted that a measurement on a transverse polarized proton target is
> equivalent to a measurement of the beam spin asymmetry on an unpolarized
> neutron target. This would be incorrect as  the measurement on a neutron
> target measures E^n, while the transverse proton target measures E^p.
> These are obviously different quantities.
>
>   2.
> Section 3.3  - Bulk Magnet.  I am not sure if we should include a fairly
> long section into the discussion, as this was only relevant for the HDIce
> option.
>
>   3.
> I have some concern on including anything on the Hall C polarized target
> in the presentation. It could cause a discussion that we not necessarily
> want as it just distracts from focusing on our solution to the HDIce
> problem. If for some reason anyone would bring it up we should be prepared
> to address it.
>
>   4.
> Minor typos: Section 4.1. The luminosity 10x10^35 = 10^36 should be just
> 10^35. The "1 mrad in azimuthal angle" should be " 1 mrad in polar
> angle".
>
>   5.
> Section 5 Physics Observables. I suggest to replace 12 GeV with 10.6 GeV
> or 11 GeV.
>
>
> Best regards,
> Volker
>
>
> ________________________________
> From: Clas12_rgh <clas12_rgh-bounces at jlab.org> on behalf of Marco
> Contalbrigo via Clas12_rgh <clas12_rgh at jlab.org>
> Sent: Monday, April 1, 2024 7:15 AM
> To: clas12_rgh at jlab.org <clas12_rgh at jlab.org>
> Subject: [Clas12_rgh] [EXTERNAL] RGH Jeopardy document
>
> Dear all,
> a draft of the RGH jeopardy document has been opened
> on overleaf. You can access it via
>
> https://urldefense.proofpoint.com/v2/url?u=https-3A__www.overleaf.com_read_hsmmsyrcbrbm-23a78ab6&d=DwIBAg&c=CJqEzB1piLOyyvZjb8YUQw&r=QWa4FYrGl2z7tyOHBIYcegdYaNKy_NApZOlUL0J3DAI&m=U0h7CvSrGo84Dcp2l9ksvTIjRAz93gEI1DoJYrNskJW6O3n-D4BvXACmk7_lCVox&s=oHCIemsXaYK6DXaH6ufh-8_RnQqK55wLu2t54a3xanU&e=
>
> Comments and suggestions are welcome. If you like to
> have writing permission, just let me know.
>
> Thanks, Marco.
>
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