[clas_members] [EXTERNAL] Re: [LOI to PAC 52] Measurement of the coherent J/psi Electroproduction off He-4 with the ALERT at 11 GeV

Wed May 1 10:28:58 EDT 2024

Hello Whitney,

I apologize if this comment comes late but hopefully it will still be useful for the development of the full proposal.

The 120 MHz mentioned in ref. 49 is the rate of particles hitting the FT at 10^35 luminosity. This is due to EM background and the rate is dominated by very low energy particles that will not pass the trigger threshold but can pollute signals produced by the electrons of interest.

The measured trigger rate in the energy range 0.5-4.5 GeV is shown in Fig. 40 of ref. 49. This was measured during RG-A, i.e. on proton target. The rate increases rapidly lowering the energy threshold and gets to the 2.5 MHz that Valery mentioned with 100 MeV threshold.

Best regards,
	Raffaella

> On Apr 30, 2024, at 6:23 PM, Armstrong, Whitney R. via clas_members <clas_members at jlab.org> wrote:
> 
> Thank you, Valery. This is very useful information.
> 
> Cheers,
> Whit
> 
> ________________________________________
> From: Valery Kubarovsky <vpk at jlab.org>
> Sent: Tuesday, April 30, 2024 4:57 PM
> To: Armstrong, Whitney R.; Volker Burkert; clas_members at jlab.org; Sangbaek Lee
> Cc: Lee, Sangbaek
> Subject: Re: [clas_members] [LOI to PAC 52] Measurement of the coherent J/psi Electroproduction off He-4 with the ALERT at 11 GeV
> 
> Dear All, The FT rate with the threshold 100 MeV has rate about 2. 5 MHz at L=10^35 with inbending TORUS configuration. Best, Valery From: Armstrong, Whitney R. <warmstrong@ anl. gov> Sent: Tuesday, April 30, 2024 16: 52 To: Volker Burkert
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> Dear All,
> The FT rate with the threshold 100 MeV has rate about 2.5 MHz at L=10^35 with inbending TORUS configuration.
> Best,
> Valery
> ________________________________
> From: Armstrong, Whitney R. <warmstrong at anl.gov>
> Sent: Tuesday, April 30, 2024 16:52
> To: Volker Burkert <burkert at jlab.org>; clas_members at jlab.org <clas_members at jlab.org>; Sangbaek Lee <sangbaek at jlab.org>; Valery Kubarovsky <vpk at jlab.org>
> Cc: Lee, Sangbaek <sangbaek.lee at anl.gov>
> Subject: [EXTERNAL] Re: [clas_members] [LOI to PAC 52] Measurement of the coherent J/psi Electroproduction off He-4 with the ALERT at 11 GeV
> 
> Dear Volker,
> 
> Thank you for sharing this information.  It is good to know our trigger rate estimate is further on the conservative side. I will add a comment to the trigger section reflecting this.
> 
> Cheers,
> Whit
> 
> 
> ________________________________________
> From: Volker Burkert <burkert at jlab.org>
> Sent: Tuesday, April 30, 2024 3:37 PM
> To: Armstrong, Whitney R.; clas_members at jlab.org; Sangbaek Lee; Valery Kubarovsky
> Cc: Lee, Sangbaek
> Subject: Re: [clas_members] [LOI to PAC 52] Measurement of the coherent J/psi Electroproduction off He-4 with the ALERT at 11 GeV
> 
> Sorry for filling your inbox with corrections. This phrase "but it will affect the resulst by a fcator maximum. " should have read: "but it will effect the results by a factor of 2 maximum". Volker From: Volker Burkert <burkert@ jlab. org>
> ZjQcmQRYFpfptBannerStart
> This Message Is From an External Sender
> This message came from outside your organization.
> 
> ZjQcmQRYFpfptBannerEnd
> Sorry for filling your inbox with corrections.
> 
> This phrase  "but it will affect the resulst by a fcator maximum." should have read: "but it will effect the results by a factor of 2 maximum".
> 
> Volker
> 
> 
> ________________________________
> From: Volker Burkert <burkert at jlab.org>
> Sent: Tuesday, April 30, 2024 4:21 PM
> To: Armstrong, Whitney R. <warmstrong at anl.gov>; clas_members at jlab.org <clas_members at jlab.org>; Sangbaek Lee <sangbaek at jlab.org>; Valery Kubarovsky <vpk at jlab.org>; Volker Burkert <burkert at jlab.org>
> Cc: Lee, Sangbaek <sangbaek.lee at anl.gov>
> Subject: Re: [clas_members] [LOI to PAC 52] Measurement of the coherent J/psi Electroproduction off He-4 with the ALERT at 11 GeV
> 
> Now with attachment
> V.
> 
> 
> 
> ________________________________
> From: clas_members <clas_members-bounces at jlab.org> on behalf of Volker Burkert via clas_members <clas_members at jlab.org>
> Sent: Tuesday, April 30, 2024 4:10 PM
> To: Armstrong, Whitney R. <warmstrong at anl.gov>; clas_members at jlab.org <clas_members at jlab.org>; Sangbaek Lee <sangbaek at jlab.org>; Valery Kubarovsky <vpk at jlab.org>
> Cc: Lee, Sangbaek <sangbaek.lee at anl.gov>
> Subject: Re: [clas_members] [LOI to PAC 52] Measurement of the coherent J/psi Electroproduction off He-4 with the ALERT at 11 GeV
> 
> Dear J/Psi enthousiasts!
> The  calculation by Acker et al does not include the "life saving" solenoid magnet.
> The attached series of graphs based on simulations from Alex Vlassov (shot from by iphone from some paper copies)  illustrates the effect of the solenoid magnet and the Moller cone. For comparison the first graph is taken with 10^33 Lumi w/o magnetic field, the second (top) with full luminosity (w/o magnetic field), the third with full luminosity and magnetic field, the fourth with full luminosity and magnetic field + a Moller shielding pipe. All background events are in the pipe.
> Of course, the FT calorimetry was not installed for this simulation, but it will affect the resulst by a fcator maximum.
> 
> So, relax, your 120MHz trigger rate will be down by a huge factor ......      In fact Valery should have those data already .
> 
> Cheers,
> Volker
> 
> 
> ________________________________
> From: clas_members <clas_members-bounces at jlab.org> on behalf of Valery Kubarovsky via clas_members <clas_members at jlab.org>
> Sent: Tuesday, April 30, 2024 1:23 PM
> To: Armstrong, Whitney R. <warmstrong at anl.gov>; clas_members at jlab.org <clas_members at jlab.org>; Sangbaek Lee <sangbaek at jlab.org>
> Cc: Lee, Sangbaek <sangbaek.lee at anl.gov>
> Subject: Re: [clas_members] [LOI to PAC 52] Measurement of the coherent J/psi Electroproduction off He-4 with the ALERT at 11 GeV
> 
> Ok, I get it. Thank you for the clarification.
> I will be happy to join the proposal.
> Valery
> 
> ________________________________
> From: Armstrong, Whitney R. <warmstrong at anl.gov>
> Sent: Tuesday, April 30, 2024 12:44
> To: Valery Kubarovsky <vpk at jlab.org>; clas_members at jlab.org <clas_members at jlab.org>; Sangbaek Lee <sangbaek at jlab.org>
> Cc: Lee, Sangbaek <sangbaek.lee at anl.gov>
> Subject: [EXTERNAL] Re: [clas_members] [LOI to PAC 52] Measurement of the coherent J/psi Electroproduction off He-4 with the ALERT at 11 GeV
> 
> This is correct for Run Group L. The trigger reconfiguration is a notable difference for this LOI compared to Run Group L.
> 
> That is, a full proposal will request new beam time with a different trigger configuration.
> 
> Please let me know if this is not clear or if you have any other concerns about the trigger or daq.
> 
> Get Outlook for Android<https://urldefense.proofpoint.com/v2/url?u=https-3A__aka.ms_AAb9ysg&d=DwMGaQ&c=CJqEzB1piLOyyvZjb8YUQw&r=i-zbrSHrZkrcFN1WPMTnag&m=JknL4WqKV76xcof7jycVEQ4WlNS9UsluPAWasIJOyZiQnedNiF62uZXMZFuixsiO&s=6EmMaLBo4GOQCa-JNHkPampcBToNb3rOAY08NqEllFg&e=>
> ________________________________
> From: clas_members <clas_members-bounces at jlab.org> on behalf of Valery Kubarovsky via clas_members <clas_members at jlab.org>
> Sent: Tuesday, April 30, 2024 11:35:19 AM
> To: clas_members at jlab.org <clas_members at jlab.org>; Sangbaek Lee <sangbaek at jlab.org>
> Cc: Lee, Sangbaek <sangbaek.lee at anl.gov>
> Subject: Re: [clas_members] [LOI to PAC 52] Measurement of the coherent J/psi Electroproduction off He-4 with the ALERT at 11 GeV
> 
> This Message Is From an External Sender
> This message came from outside your organization.
> 
> Dear Sangbaek and Whitney,
> I have some concerns about proposed trigger for the ALERT experiment. As for my knowledge, we don't expect any trigger from the ALERT detector to be incorporated to the CLAS12 trigger system.
> So, the trigger 1 and trigger 2 (see below the extraction from your proposal) just will not work.
> Let me know what you think.
> Best regards,
> Valery
> 
> Page 13:
> At the nominal CLAS12 luminosity, O(1035 cm−2s−1), the forward tagger subsystem trigger rate is NFT = 120 MHz [49]. Clearly a trigger that solely relies on FT cannot be handled by the current CLAS12 DAQ without significant inefficiency– noting the nominal DAQ trigger rate is 20 kHz [50].
> The first trigger (Trigger 1) is focused on the scattered electron detection and 4He detection in ALERT. The accidental coincidence event rate of FT and ALERT can be estimated as Ncoin = NFTNALERTτ, where τ is the coincidence time window. The estimated background rates are shown in Fig. 2.5. We conservatively estimate NALERT as 1 kHz over the momentum range 0.3 MeV/c < p < 1.1 GeV/c. The coincidence time window is conservatively set to 100 ns, which is on the order of the AHDC drift time [51]. The total coincidence trigger rate is then estimated to be roughly 12 kHz.
> The second trigger (Trigger 2) configuration is based on the coincidence of ALERT and FD. The FD trigger condition is either on the scattered electron, or dilepton pair from J/ψ. Both triggers are operating for the existing experiments [50]. Target and Beam Configuration
> 
> ________________________________
> From: clas_members <clas_members-bounces at jlab.org> on behalf of Sangbaek Lee via clas_members <clas_members at jlab.org>
> Sent: Tuesday, April 30, 2024 08:39
> To: clas_members at jlab.org <clas_members at jlab.org>
> Cc: Sangbaek Lee <sangbaek.lee at anl.gov>
> Subject: [clas_members] [LOI to PAC 52] Measurement of the coherent J/psi Electroproduction off He-4 with the ALERT at 11 GeV
> 
> Dear colleagues,
> 
> I am pleased to circulate this PAC 52 Letter of Intent (LOI) "Measurement of the coherent J/psi Electroproduction off He-4 with the ALERT at 11 GeV" after review.
> 
> The letter can be found at the following link: https://www.jlab.org/Hall-B/shifts/admin/paper_reviews/2024/Coherent_jpsi_electroproduction_pac52_without_beamtime_estimate.pdf-4616787-2024-04-29-v4.pdf<https://urldefense.proofpoint.com/v2/url?u=https-3A__urldefense.us_v3_-5F-5Fhttps-3A__www.jlab.org_Hall-2DB_shifts_admin_paper-5Freviews_2024_Coherent-5Fjpsi-5Felectroproduction-5Fpac52-5Fwithout-5Fbeamtime-5Festimate.pdf-2D4616787-2D2024-2D04-2D29-2Dv4.pdf-5F-5F-3B-21-21G-5FuCfscf7eWS-21cq0F4mbvGzEv5YLig16xzqXKop-5Fs0fJ5-2DKculAIZcMWNsT7QfxChwVujJqSqchTvZDBqi-5F-2D9y4pp5GNbfcmfxx52NZMK7g-24&d=DwMGaQ&c=CJqEzB1piLOyyvZjb8YUQw&r=i-zbrSHrZkrcFN1WPMTnag&m=JknL4WqKV76xcof7jycVEQ4WlNS9UsluPAWasIJOyZiQnedNiF62uZXMZFuixsiO&s=tjpsMtGkgO0rcbuFPzOYzzgATUGepYu-R4MfV1gVQbw&e=><https://urldefense.proofpoint.com/v2/url?u=https-3A__urldefense.us_v3_-5F-5Fhttps-3A__www.jlab.org_Hall-2DB_shifts_admin_paper-5Freviews_2024_Coherent-5Fjpsi-5Felectroproduction-5Fpac52-5Fwithout-5Fbeamtime-5Festimate.pdf-2D4616787-2D2024-2D04-2D29-2Dv4.pdf-2A3Chttps-3A_-2Aurldefense.proofpoint.com_v2_url-3Fu-3Dhttps-2D3A-5F-5Furldefense.us-5Fv3-5F-2D5F-2D5Fhttps-2D3A-5F-5Fwww.jlab.org-5FHall-2D2DB-5Fshifts-5Fadmin-5Fpaper-2D5Freviews-5F2024-5FCoherent-2D5Fjpsi-2D5Felectroproduction-2D5Fpac52-2D5Fwithout-2D5Fbeamtime-2D5Festimate.pdf-2D2D4616787-2D2D2024-2D2D04-2D2D29-2D2Dv4.pdf-2D5F-2D5F-2D3B-2D21-2D21G-2D5FuCfscf7eWS-2D21cq0F4mbvGzEv5YLig16xzqXKop-2D5Fs0fJ5-2D2DKculAIZcMWNsT7QfxChwVujJqSqchTvZDBqi-2D5F-2D2D9y4pp5GNbfcmfxx52NZMK7g-2D24-26d-3DDwMGaQ-26c-3DCJqEzB1piLOyyvZjb8YUQw-26r-3Di-2DzbrSHrZkrcFN1WPMTnag-26m-3DJknL4WqKV76xcof7jycVEQ4WlNS9UsluPAWasIJOyZiQnedNiF62uZXMZFuixsiO-26s-3DtjpsMtGkgO0rcbuFPzOYzzgATUGepYu-2DR4MfV1gVQbw-26e-3D-2A3E-5F-5F-3BJS8l-21-21G-5FuCfscf7eWS-21a4EDfAa9-5FnICHZZlvhTZIr-5FcSTIQaqZ2mG6whRK6x-5Fq5utghtQaAXLYkQPiVkD5q57tAC-5FY44D5W-24&d=DwIGaQ&c=CJqEzB1piLOyyvZjb8YUQw&r=nhU86tu_xVxwkH2JyhlcQb1jyw6CUjquEwQhqpV3cJI&m=i076y0Zy6s4Ohzmhs3ZRxp2PQdjoF1u2SdGDq4IJYbxFc3NK92YAxIZ6BmBloKLd&s=LPZq2nFbhw9uS9ah-hdKAhPn2idMlxgEns9fxFLFpM0&e= 
>
> We aim to measure the location of a diffraction minimum in the differential cross section to compare the gluonic gravitational form factor and charge form factor. The secondary goal is to extract the gluonic gravitational form factors of He-4.
> 
> Please let us know if you would like to opt-in, by contacting me at sangbaek.lee at anl.gov<mailto:sangbaek.lee at anl.gov> and Whitney Armstrong at warmstrong at anl.gov<mailto:warmstrong at anl.gov>.
> Also, if you have any comments or questions, please send them to me and to Whitney Armstrong.
> The letter will be submitted to the PAC 52 by 9 a.m. JLab time on Wednesday, 5/1/2024.
> 
> Sincerely,
> Sangbaek and Whitney
> 
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