[Rgd-ana] [EXTERNAL] Re: CAA on vector meson production on nuclear targets

Mon Sep 15 03:57:01 EDT 2025

Hello Lamiaa,

I have added your name to the document.
I plan to send it today in the early pm European time.

Concerning your comments I have answered to each below. In general, I do 
agree with all, and we will need to implement common analysis strategies 
and adapt the ones used so far in RGA/RGB to this CAA.

Best,
Pierre

Le 2025-09-15 06:06, El Fassi, Lamiaa a écrit :
> Dear Pierre, Dear Richard,
> 
>  Thank you once more for sharing your CAA draft and for the invitation
> to sign it. I will be pleased to do so and will send you the full list
> of interested RG-D folks after this Wednesday's meeting, in case they
> haven't contacted you yet about it.
> 
>  Those are some minor comments and requests for the coordination of
> these analyses with the run group:
> 
>  	*
> In my understanding, based on what has been mentioned about PIDs, the
> pilot analysis presented in the shared CAA relies only on the EB,
> except for the BDT-based lepton PID, which is applied to positrons
> only; is that right? I am unsure if the same method has been
> considered at any point to improve electron ID and reduce its \pi^-
> contamination?

We also have a BDT PID for electron, yet much less important as the 
contamination is lower in the JPsi analysis because of the exclusivity 
of the final state.
For the complete analysis, we should surely use positron and electron 
BDT PID, once retrain specifically for RGD/RGE

> 	*
> I believe the sampling fraction shown in Fig. 1 is integrated over all
> sectors, right? I wonder whether similar behavior has been observed in
> various sectors, or whether it has been verified that this ML
> technique to refine lepton PID is not sector-dependent. I glanced at
> Mariana's note (Ref. 38) and didn't see any sector-wise plots.
> However, the parametrization of the SF_p mean and sigma (Eq.2) is
> mentioned to be run-dependent and calibrated for each sector. If it's
> the case, may I know which parametrization you are using for RG-D
> data, or are you simply using the standard parametrization stored in
> CCDB
> (https://clasweb.jlab.org/cgi-bin/ccdb/show_request?request=/calibration/eb/electron_sf:12706:default:2021-02-23_12-13-37),
> as I don't see any entry specific to RG-D run ranges besides this one
> that goes to infinity. While this SF parametrization is for e-s, what
> about positrons? (_please see next, too_)

So far the BDT is trained on RGA simulations. So there is indeed a lot 
of room for improvement, yet the overall performances should not change 
order of magnitudes.
The approach now is sector dependent but on simulations. The effect of 
sector dependance in real data is correct later using an efficiency 
correction factor. We plan to do something similar for this analysis.

> 	*
> In case you are using your own SF parametrization, it would be
> appreciated if you could share it with the run group members. That
> brings me to the request to coordinate the common aspects, such as
> PIDs, vertex cuts, etc., with the RG to optimize the efforts,
> cross-check results, and also allow the "junior" RG-D analyzers, such
> as graduate students, to benefit from your experience of analyzing
> different datasets.

As mentionned, the approach now is based on RGA simulations, hence we do 
not have the SF parametrization.
For the rest; I totally agree, we should use as much common cuts/tools 
and not reinvent the wheel for each analysis.

> 	*
> Please get in touch with Mathieu for the vertex cuts he developed,
> especially to separate Cu and Sn targets. I understand that these
> foils are currently not separated due to a lack of statistics, but
> that will eventually be done. Your feedback on that will also be
> appreciated.

Sure, we'll do that

> 	*
> For the coordination of efforts, cuts, and/or corrections, we could
> have some common repository where various routines are stored, but
> this is something that we could discuss a bit later as all analyses
> advance.

Totally agree on this

> 	*
> In Sub. 3.3.1, it's mentioned that a cut of 4 ns is applied to the
> vertex time difference between e-s and other particles to ensure they
> all originate from the same beam bucket, but I believe a 2 ns cut
> should be used instead, since the beam was simultaneously delivered to
> 3 halls, not four, during the RG-D run; see this logbook entry [1]!

Thank you for this point. We'll include this.
I don't believe this has a large effect in this case, considering the 
full exclusivity of the kaon final state, but the complete analysis will 
definitely have a 2ns cut.

> 	*
> I am a bit curious to know whether you have developed any strategy yet
> on how to combine RG-D and RG-E datasets, as we ran with different
> torus and target configurations and vertex positions. That may have an
> impact on your systematic budget, as cuts for one dataset may not work
> for the other, etc.

This is a very good point. So far we are considering to have each target 
and each run group as a different analysis. From my point of view, the 
best way to combine the results would be at the cross-section level, but 
this is still to be discussed further

> 
>  That is all for now. Please keep us updated with your progress.
> Again, your team's efforts to advance these analysis channels are much
> appreciated.
> 
>  	*
> 
>  Best,
> 
>  Lamiaa
> 
>  
> **************************************************************************
> 
>  * Assoc. Prof. Lamiaa El Fassi  /  email: le334 at msstate.edu
> * Chair-Elect, Southeastern Section [2], American Physical Society [3]
> 
>  
> **************************************************************************
> 
>  * (she/her/hers [4])
>  * Phone: (662) 325-0627    /    Fax:  (662) 325-8898
>  * URL: http://le334.physics.msstate. [5] [5]edu/ [5]
>  * Department of Physics and Astronomy
>  * 355 Lee Blvd, 125 Hilbun Hall
> 
>  * P.O.Box 5167
>  * Mississippi State, MS 39762
>  
> ***************************************************************************
> 
> 
> -------------------------
> 
>  From: El Fassi, Lamiaa <le334 at msstate.edu>
> Sent: Thursday, September 11, 2025 9:19 PM
> To: pierrec at jlab.org <pierrec at jlab.org>; Richard Tyson
> <tyson at jlab.org>
> Cc: rgd-ana at jlab.org <rgd-ana at jlab.org>
> Subject: Re: CAA on vector meson production on nuclear targets
> 
>  Dear Pierre,
> 
>  Thank you for sharing the CAA and for presenting the progress the
> team has made so far in exploring new analysis channels, extending the
> initial RG-D program.
> 
>  As you mentioned, all run-group members are welcome to read the
> current draft and share comments. Thank you for offering to sign it.
> 
>  This serves as an acknowledgment of receiving your write-up, and more
> details should follow.
> 
>  Best,
> 
>  Lamiaa
> 
>  
> **************************************************************************
> 
>  * Assoc. Prof. Lamiaa El Fassi  /  email: le334 at msstate.edu
> * Chair-Elect, Southeastern Section [2], American Physical Society [3]
> 
>  
> **************************************************************************
> 
>  * (she/her/hers [4])
>  * Phone: (662) 325-0627    /    Fax:  (662) 325-8898
>  * URL: http://le334.physics.msstate. [5] [5]edu/ [5]
>  * Department of Physics and Astronomy
>  * 355 Lee Blvd, 125 Hilbun Hall
> 
>  * P.O.Box 5167
>  * Mississippi State, MS 39762
> ***************************************************************************
> 
> 
> -------------------------
> 
>  From: pierrec at jlab.org <pierrec at jlab.org>
> Sent: Thursday, September 11, 2025 3:31 AM
> To: El Fassi, Lamiaa <le334 at msstate.edu>
> Cc: rgd-ana at jlab.org <rgd-ana at jlab.org>
> Subject: CAA on vector meson production on nuclear targets
> 
> Dear Lamiaa, and RG-D enthusiasts,
> 
> First of all; thank you for having us present our work yesterday
> during
> the meeting.
> We are looking forward to analyse the full RG-D dataset !
> 
> Since, the meeting, we have included to the CAA draft some comments we
> have received. The current version is attached to this email.
> We plan to send the final version of the document on Monday 15th of
> September.
> 
> If you'd like to sign it, or if you have further comments, please let
> us
> know and we will be glad to change it accordingly by Monday.
> 
> Cheers,
> Pierre and Richard
> 
> Links:
> ------
> [1] https://logbooks.jlab.org/entry/4189477
> [2] 
> https://urldefense.proofpoint.com/v2/url?u=https-3A__engage.aps.org_sesaps_home&d=DwMFAw&c=CJqEzB1piLOyyvZjb8YUQw&r=V2r__2wJp8te1D3KE-pRN42cUD6b8KLx_-E8uU77JCs&m=mbe2k09Rlh2Ng1Qp8jrtXfvdT26vlZBqctRnsR-6TuV6ev8XgoU6y-kie--GVb0P&s=CaymKXf11hueSy2SFjvBVa3dYGYh_PWKEHzyyxJncdg&e=
> [3] 
> https://urldefense.proofpoint.com/v2/url?u=https-3A__www.aps.org_&d=DwMFAw&c=CJqEzB1piLOyyvZjb8YUQw&r=V2r__2wJp8te1D3KE-pRN42cUD6b8KLx_-E8uU77JCs&m=mbe2k09Rlh2Ng1Qp8jrtXfvdT26vlZBqctRnsR-6TuV6ev8XgoU6y-kie--GVb0P&s=F5TRUWn6b6XYXUc6PUXmHU9F0y_Zs81VnxW7G4YMKpo&e=
> [4] 
> https://urldefense.proofpoint.com/v2/url?u=https-3A__www.name-2Dcoach.com_lamiaa-2Delfassi-3Fpreview-3Don&d=DwMFAw&c=CJqEzB1piLOyyvZjb8YUQw&r=V2r__2wJp8te1D3KE-pRN42cUD6b8KLx_-E8uU77JCs&m=mbe2k09Rlh2Ng1Qp8jrtXfvdT26vlZBqctRnsR-6TuV6ev8XgoU6y-kie--GVb0P&s=e6YNpbz6k5xCdkhXfFac0_Hr2tr-SitWwipwa5T5l3c&e=
> [5] 
> https://urldefense.proofpoint.com/v2/url?u=http-3A__le334.physics.msstate.edu_&d=DwMFAw&c=CJqEzB1piLOyyvZjb8YUQw&r=V2r__2wJp8te1D3KE-pRN42cUD6b8KLx_-E8uU77JCs&m=mbe2k09Rlh2Ng1Qp8jrtXfvdT26vlZBqctRnsR-6TuV6ev8XgoU6y-kie--GVb0P&s=d9EPOWJOZQXB0za-X2FYxLXmztbb_PJAe0l2basuFE8&e=