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Investigation of the background in coherent $J/\psi$ production at the EIC
by Wan Chang, Elke-Caroline Aschenauer, Mark D. Baker, Alexander Jentsch, Jeong-Hun Lee, Zhoudunming Tu, Liang Zheng
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Submission summary
| Authors (as registered SciPost users): | Wan Chang |
| Submission information | |
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| Preprint Link: | scipost_202108_00003v1 (pdf) |
| Date submitted: | 2021-08-02 17:34 |
| Submitted by: | Chang, Wan |
| Submitted to: | SciPost Physics Proceedings |
| Proceedings issue: | 28th Annual Workshop on Deep-Inelastic Scattering (DIS) and Related Subjects (DIS2021) |
| Ontological classification | |
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| Academic field: | Physics |
| Specialties: |
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| Approach: | Experimental |
Abstract
Understanding fundamental properties of nucleons and nuclei are among the most important scientific goals of the next-generation machine, the Electron-Ion Collider (EIC). With the unprecedented versatility provided by the EIC, it will provide answers to many standing puzzles and open questions in modern nuclear physics. One of the golden measurements at the EIC is coherent vector meson production in electron-nucleus (eA) scattering in order to obtain the spatial gluon density distribution in heavy nuclei. This requires the experiment to overcome an overwhelmingly large background arising from the incoherent diffractive production, where the nucleus mostly breaks up into fragments of particles in the far-forward direction close to the hadron beam rapidity. In this talk, we systematically study the rejection of incoherent $J/\psi$ production by vetoing products from the nuclear breakup - protons, neutrons, and photons, which is modeled with the BeAGLE event generator and the most up-to-date EIC Far-forward Interaction Region design.
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Reports on this Submission
Anonymous Report 1 on 2022-2-28 (Invited Report)
- Cite as: Anonymous, Report on arXiv:scipost_202108_00003v1, delivered 2022-02-28, doi: 10.21468/SciPost.Report.4556
Report
The paper, Chang et al., "Investigation of the background in coherent J/ψ production at the EIC" a study of rejecting incoherent diffractive production of J/ψ by vetoing products of nuclear breakup is presented. The paper is well written, does a good job describing the motivation for the study and the event generator used in the study, and also clearly lays out the detector geometry considered for the future Electron-Ion Collider. The results in the manuscript are clear and mostly well explained.
This manuscript fulfills the requirements to be published in this journal.
There is one minor comment, in the abstract there is a line " In
this talk..." which I think should be changed to reflect that this is a written report.
I also have a comment regarding the proton vetos discussed in the Results section. In Fig. 1 the results of the study are shown with several of the different vetos applied, which are discussed in the text. However, the text mentions that vetos which have a small impact on the results are not shown. Those vetos which have a small impact are numbered 1, 3, and 5. The reasoning as to why veto 1 is not included is satisfactorily discussed. However vetos 3 and 5 are not. It might be worthwhile to add a single sentence or so describing why those vetos do not significantly impact the results. If I have missed a very obvious reason as to why this is the case, please let me know.
Author: Wan Chang on 2022-03-03 [id 2263]
(in reply to Report 1 on 2022-02-28)Dear Editors,
Thank you for forwarding to us the referee’s report on our submitted manuscript.
I thank the referee for the careful reading and the positive assessment of the manuscript. I have addressed all the comments and suggestions in the revised version and the reply submitted here.
Response: Thanks for spotting this point and it is now corrected.
Response: We would like to thank the referee for bringing up this good question. In the BeAGLE model, the incoherent J/\psi is produced together with one or more ions and, protons, neutrons, photons, or any combination of them depending on the excitation energy. ~94% of these incoherent events have at least one neutron produced, and ZDC has a good acceptance for neutrons, therefore, only less than 10% of events survived after veto.2. Because of the rigidity change, the RP has an insignificant contribution for proton measurements, while most of the protons within small scattering angle are detected by OMD. Therefore, veto.3 and veto.5 have a small impact on vetoing incoherent events. We have rephrased the sentence at the end of page.3 as follows,
Figure 1 shows, that the vetoing on protons, neutrons, and photons are all important and contribute to a significant reduction of the background. After veto.7, the residual contribution is about 1--10% of the total events, depending on the value of |t|. -> There are ~94\% of these incoherent events that have at least one neutron produced, and ZDC has a good acceptance for neutrons. Therefore, only less than 10% of events survived after veto.2. Because of the rigidity change, the RP and B0 made an insignificant contribution for proton measurements, while most of the protons within small scattering angle are detected by OMD. Figure 1 shows that after the vetoing on neutrons, protons, and photons, the residual contribution is about 1--10% of the total events, depending on the value of |t|.