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Now with attachment</div>
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V.</div>
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<div id="divRplyFwdMsg" dir="ltr"><span style="font-family: Calibri, sans-serif; font-size: 11pt; color: rgb(0, 0, 0);"><b>From:</b> clas_members <clas_members-bounces@jlab.org> on behalf of Volker Burkert via clas_members <clas_members@jlab.org><br>
<b>Sent:</b> Tuesday, April 30, 2024 4:10 PM<br>
<b>To:</b> Armstrong, Whitney R. <warmstrong@anl.gov>; clas_members@jlab.org <clas_members@jlab.org>; Sangbaek Lee <sangbaek@jlab.org>; Valery Kubarovsky <vpk@jlab.org><br>
<b>Cc:</b> Lee, Sangbaek <sangbaek.lee@anl.gov><br>
<b>Subject:</b> Re: [clas_members] [LOI to PAC 52] Measurement of the coherent J/psi Electroproduction off He-4 with the ALERT at 11 GeV</span>
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Dear J/Psi enthousiasts!</div>
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The calculation by Acker et al does not include the "life saving" solenoid magnet. </div>
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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. </div>
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Of course, the FT calorimetry was not installed for this simulation, but it will affect the resulst by a fcator maximum. </div>
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So, relax, your 120MHz trigger rate will be down by a huge factor ...... In fact Valery should have those data already .</div>
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Cheers, </div>
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Volker</div>
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<div id="x_divRplyFwdMsg" dir="ltr"><span style="font-family: Calibri, sans-serif; font-size: 11pt; color: rgb(0, 0, 0);"><b>From:</b> clas_members <clas_members-bounces@jlab.org> on behalf of Valery Kubarovsky via clas_members <clas_members@jlab.org><br>
<b>Sent:</b> Tuesday, April 30, 2024 1:23 PM<br>
<b>To:</b> Armstrong, Whitney R. <warmstrong@anl.gov>; clas_members@jlab.org <clas_members@jlab.org>; Sangbaek Lee <sangbaek@jlab.org><br>
<b>Cc:</b> Lee, Sangbaek <sangbaek.lee@anl.gov><br>
<b>Subject:</b> Re: [clas_members] [LOI to PAC 52] Measurement of the coherent J/psi Electroproduction off He-4 with the ALERT at 11 GeV</span>
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Ok, I get it. Thank you for the clarification.</div>
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I will be happy to join the proposal.</div>
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Valery</div>
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<div id="x_x_divRplyFwdMsg" dir="ltr" style=""><span style="font-family: Calibri, sans-serif; font-size: 11pt; color: rgb(0, 0, 0);"><b>From:</b> Armstrong, Whitney R. <warmstrong@anl.gov><br>
<b>Sent:</b> Tuesday, April 30, 2024 12:44<br>
<b>To:</b> Valery Kubarovsky <vpk@jlab.org>; clas_members@jlab.org <clas_members@jlab.org>; Sangbaek Lee <sangbaek@jlab.org><br>
<b>Cc:</b> Lee, Sangbaek <sangbaek.lee@anl.gov><br>
<b>Subject:</b> [EXTERNAL] Re: [clas_members] [LOI to PAC 52] Measurement of the coherent J/psi Electroproduction off He-4 with the ALERT at 11 GeV</span>
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<div style="direction: ltr;">This is correct for Run Group L. The trigger reconfiguration is a notable difference for this LOI compared to Run Group L.</div>
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<div style="direction: ltr;">That is, a full proposal will request new beam time with a different trigger configuration.</div>
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<div style="direction: ltr;">Please let me know if this is not clear or if you have any other concerns about the trigger or daq. </div>
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<div id="x_x_x_ms-outlook-mobile-signature" dir="auto" style="">Get <a href="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=" id="OWA90bcf6e1-2513-fed6-d8ba-2bf1f4f55bdf" class="x_x_OWAAutoLink" data-auth="NotApplicable">
Outlook for Android</a></div>
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<div id="x_x_x_divRplyFwdMsg" dir="ltr" style=""><span style="font-family: Calibri, sans-serif; font-size: 11pt; color: rgb(0, 0, 0);"><b>From:</b> clas_members <clas_members-bounces@jlab.org> on behalf of Valery Kubarovsky via clas_members <clas_members@jlab.org><br>
<b>Sent:</b> Tuesday, April 30, 2024 11:35:19 AM<br>
<b>To:</b> clas_members@jlab.org <clas_members@jlab.org>; Sangbaek Lee <sangbaek@jlab.org><br>
<b>Cc:</b> Lee, Sangbaek <sangbaek.lee@anl.gov><br>
<b>Subject:</b> Re: [clas_members] [LOI to PAC 52] Measurement of the coherent J/psi Electroproduction off He-4 with the ALERT at 11 GeV</span>
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This Message Is From an External Sender</div>
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This message came from outside your organization.</div>
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Dear Sangbaek and Whitney,</div>
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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.</div>
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So, the trigger 1 and trigger 2 (see below the extraction from your proposal) just will not work.</div>
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Let me know what you think.</div>
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Best regards,</div>
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Valery</div>
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Page 13:</div>
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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]. </div>
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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. </div>
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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</div>
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<div id="x_x_x_x_divRplyFwdMsg" dir="ltr" style=""><span style="font-family: Calibri, sans-serif; font-size: 11pt; color: rgb(0, 0, 0);"><b>From:</b> clas_members <clas_members-bounces@jlab.org> on behalf of Sangbaek Lee via clas_members <clas_members@jlab.org><br>
<b>Sent:</b> Tuesday, April 30, 2024 08:39<br>
<b>To:</b> clas_members@jlab.org <clas_members@jlab.org><br>
<b>Cc:</b> Sangbaek Lee <sangbaek.lee@anl.gov><br>
<b>Subject:</b> [clas_members] [LOI to PAC 52] Measurement of the coherent J/psi Electroproduction off He-4 with the ALERT at 11 GeV</span>
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<div style="direction: ltr;">Dear colleagues,</div>
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<div style="direction: ltr;">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.</div>
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<div style="direction: ltr;">The letter can be found at the following link: <a href="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=" id="OWAb089b20d-bbd2-d4c9-a043-5b3dd73f49c3" class="x_x_x_x_OWAAutoLink" data-auth="NotApplicable">
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</a> </div>
<div style="direction: ltr;">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.</div>
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<div style="direction: ltr;">Please let us know if you would like to opt-in, by contacting me at
<a href="mailto:sangbaek.lee@anl.gov" id="OWA6a1827dd-cd2c-5fb3-9a3c-78afb54be496" class="x_x_x_x_OWAAutoLink">
sangbaek.lee@anl.gov</a> and Whitney Armstrong at <a href="mailto:warmstrong@anl.gov" id="OWAfcc88e55-9d34-48c7-9c28-6948a2c30b39" class="x_x_x_x_OWAAutoLink">
warmstrong@anl.gov</a>.</div>
<div style="direction: ltr;">Also, if you have any comments or questions, please send them to me and to Whitney Armstrong.</div>
<div style="direction: ltr;">The letter will be submitted to the PAC 52 by 9 a.m. JLab time on Wednesday, 5/1/2024.</div>
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<div style="direction: ltr;">Sincerely,</div>
<div style="direction: ltr;">Sangbaek and Whitney</div>
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