{"id":"e14151b8-c9fc-4345-af01-6aab7248ebed","arxiv_id":"1908.11792","paper_version":1,"verdict":"UNVERDICTED","confidence":"LOW","novelty_score":0.0,"correctness_risk":"unknown","formal_verification":"none","parameter_count":0,"one_line_summary":"A workshop report summarizing talks and organizer conclusions on central exclusive production at the LHC, focusing on odderon searches, glueballs, and the need for forward proton detection.","lead":"This paper is a report by the organizers of a 2019 workshop on central exclusive production at the LHC. It summarizes the talks and lists the organizers' conclusions about studying pomerons, odderons, and glueballs in high-energy proton collisions.","discovery_kind":"review","skeptic_critique":{"model":"deepseek-v4-flash","headline":"Organizers' CEP-odderon/glueball optimism depends on unproven LHC capability to tag very small |t| and cover |η| to 4–5; without it, photon-exchange separation and odderon studies may be infeasible.","rationale":"The paper is an organizers' workshop report, not a research preprint with a testable central claim; it summarizes talks and gives programmatic opinions. Therefore the reader's UNVERDICTED verdict is appropriate. The weakest assumption in the forward-looking conclusions is indeed the experimental feasibility of the required measurements: very small-|t| proton tagging, particle identification, and large-|η| coverage. The authors themselves flag this as a condition ('Only then will one be able to isolate and study photon exchange reactions'), but they do not demonstrate that LHC experiments meet it. My stress-test does not uncover an internal inconsistency or a mathematical flaw; rather, it identifies that the headline conclusions are conditional on an unverified experimental premise. Because the document's genre already prevents a fully testable claim, this concern does not change the verdict. The proposed concrete test is a physics-feasibility study that would determine whether the programmatic CEP-odderon/glueball agenda is actionable with actual LHC detectors.","tokens_in":4676,"tokens_out":4093,"duration_ms":39957,"concrete_test":"Compute, using the tensor-pomeron/vector-odderon amplitudes of [2,3] together with photon exchange and the absorptive corrections of [19], the expected yields for a proposed odderon-sensitive CEP channel (e.g., pp → p + η_c + p at √s = 13 TeV) after folding in the actual acceptance and efficiency maps of the currently installed or planned LHC forward proton detectors (ALFA, AFP, TOTEM) and central particle identification. If the odderon-sensitive observable, such as the φpp distribution or the t-dependence, has no statistically significant separation over the |t| range where both protons are simultaneously tagged, then the organizers' 'excellent possibilities' claim is not supported by the available instrumentation.","verdict_should_be":"UNCHANGED","load_bearing_attack":"The report's forward-looking conclusion, that CEP offers excellent possibilities for odderon and glueball studies, is conditional on an experimental capability that the authors themselves identify as required: measuring very small |t| via both outgoing protons, particle identification, and acceptance up to |η| ≈ 4–5. The document states that only then can photon exchange be isolated and odderon effects separated (penultimate bullet, p.3), but it provides no evidence that current or planned LHC forward detectors reach the necessary |t| range, nor that central PID and rapidity coverage are available. Since odderon searches must separate a competing photon-exchange amplitude through t-dependence at very small |t|, and since Alan Martin's summary notes absorption suppression can reduce cross sections by an order of magnitude, the programmatic claim could fail if instrumentation excludes the interesting kinematic region. This is not an internal inconsistency, but a feasibility premise that is unverified within the document.","agreement_with_reader":"agree"},"referee_report":{"model":"deepseek-v4-flash","summary":"This manuscript is a short document by the organisers of the EMMI workshop 'Central exclusive production at the LHC', held at Heidelberg in February 2019. It records the main topics presented at the meeting: the tensor-pomeron/vector-odderon effective model, a Veneziano-type resonance approach, holographic predictions for glueballs, the GenEx and DRgen event generators, and Alan Martin's discussion of absorption corrections and the status of the odderon. The authors then give their own conclusions, which are that CEP reactions will allow detailed studies of pomeron couplings, offer excellent possibilities for odderon searches, are prime places to search for glueballs, and would benefit considerably from measuring the complete final state with particle identification and forward coverage up to |η| ≈ 4–5.","tokens_in":4979,"tokens_out":3109,"duration_ms":30666,"significance":"The paper contains no new calculations, data, or derivations; its value is as a concise and accessible synthesis of the current state of CEP physics and of the open experimental and theoretical questions. It is useful as a documented starting point for future studies and for experimental planning, and it does a service by explicitly recording caveats, such as Alan Martin's view that existing odderon evidence at small |t| is not yet convincing and that absorption reduces Born-level cross sections by an order of magnitude or more. The strength of the paper is that it honestly reports the model-dependent nature of the theoretical approaches. Its main limitation is that its forward-looking conclusions are optimistic statements conditioned on experimental capabilities that are not demonstrated or referenced in the manuscript.","major_comments":[{"comment":"The central claims 'CEP offers excellent possibilities to look for odderon-exchange effects' and that 'the search for and the characterisation of glueballs are prime topics' are presented as unqualified conclusions, yet the same page states that isolating photon exchange and distinguishing odderon contributions requires measurements at very small |t|, and that the relevant reggeon/glueball studies need |η| coverage up to 4–5. The manuscript gives no evidence that current or planned LHC forward detectors (e.g., AFP, CT-PPS, ALFA, or Roman-pot systems) achieve the required small-|t| tag, nor that central PID and pseudorapidity coverage out to 4–5 are available. Since the entire programmatic recommendation depends on this capability, the authors should either cite the actual detector reach or explicitly reframe the conclusions as conditional on future instrumentation. Without this, the proposal is unverified.","section":"Concluding bullets, p.3"},{"comment":"The body reports that eikonal and Sudakov suppression can reduce cross sections by factors of order 10 and larger, and that this absorption must be taken into account in odderon searches. The concluding bullets, however, do not factor this suppression into the claim of 'excellent possibilities', so the summary message is more optimistic than the quantitative evidence presented in the body. The authors should specify whether the proposed CEP studies remain sensitive (e.g., in rate or in observable asymmetries) after the reported suppression, or temper the conclusion accordingly.","section":"Alan Martin paragraph, p.2, and concluding bullets, p.3"}],"minor_comments":[{"comment":"The exchange-object labels in the figure caption (intended to show pomeron, odderon, reggeon, and photon lines) appear garbled in the compiled text; the caption should be fixed so that each exchange type is legible.","section":"Figure 1 caption"},{"comment":"The author name 'A. Schning' should read 'A. Schönning'.","section":"Reference [4]"},{"comment":"These references are bare GitHub URLs without commit identifiers or retrieval dates; for archival purposes, the authors should either cite published papers describing the generators or add a retrieval date and version.","section":"References [16] and [18]"},{"comment":"The statement that reggeon contributions are 'non-negligible for large |η|' would be clearer with an indication of the kinematic region in mX where this expectation holds, since the size of reggeon contributions is known to depend on the central mass.","section":"Concluding bullet on reggeons, p.3"}],"recommendation":"major_revision","confidential_remarks":"This manuscript is not a research paper in the usual sense; it is a workshop summary with programmatic conclusions. If the journal's scope is strictly original research, the editors may wish to consider whether this format is appropriate. The self-citation rate is high but natural for a text by workshop organisers; I would not flag it further. The main scientific concern—unverified experimental feasibility for the small-|t| and large-|η| requirements—is fixable by adding concrete detector information or softening the conclusions, and I do not see an internal inconsistency or circularity in the arguments."},"author_rebuttal":null,"desk_editor":{"model":"deepseek-v4-flash","letter":"This is a short organizers' report from a one-day EMMI workshop on central exclusive production at the LHC. There is no new calculation, no data, no derivation; what you get is a clean, honest summary of where the field stands and a set of cautious recommendations. It should be read as a community note, not a research preprint.\n\nIt does several things well. The organizers give a balanced picture: they report the tensor-pomeron/vector-odderon effective model as one approach, they mention the Veneziano-type alternative, and they do not hide the fact that the theory is model-based and only partly checked against QCD. They also include Alan Martin's sobering points on absorption suppression (order-of-magnitude reductions) and his view that the existing odderon evidence from elastic scattering is not yet convincing. That is a genuinely useful counterweight to the more optimistic talk summaries. The final bullets are careful: they say CEP \"offers excellent possibilities\" for odderon searches, but immediately add that this requires great experimental effort, and that isolating photon exchange needs good small-|t| proton tagging, PID, and coverage up to |η| ≈ 4–5.\n\nThe soft spots are mostly inherent to the genre. The forward-looking conclusions are opinions formed from talks, not results established in this document; the accuracy of the attributed talk content cannot be verified from the text alone. The stress-test note worries that the odderon/glueball program depends on instrumentation that may not exist. That concern is partly pre-empted by the authors' own hedging: they do not claim these capabilities are currently available, only that the studies would benefit considerably from them. Still, a reader less familiar with LHC forward physics might walk away thinking the program is further along than it is. The paper could have been more explicit about which of these capabilities are planned versus merely desirable.\n\nThe self-citations are not a problem here; they point to prior work that underpins the talks and are appropriate in a summary of this kind.\n\nWho is this for? People working on CEP, diffraction, or forward detector planning at the LHC. It is a useful record of where the field stood in 2019 and what the organizers think the priorities should be. I would not bring it to a reading group as a substantive physics paper, and I would not cite it in my own work, but I would point a student to it for a quick orientation.\n\nOn peer review: this does not deserve referee time as a research article. It is a workshop report, and the appropriate venue is a proceedings volume or simply the arXiv, where it already lives. A journal that publishes meeting summaries could accept it after a light editorial check, but a serious editor should desk-reject it for a research track.","headline":"Honest, well-hedged workshop summary on CEP, no new physics; its odderon/glueball optimism is explicitly conditional on forward-detector capabilities the authors themselves flag.","tokens_in":5287,"tokens_out":1885,"would_cite":false,"duration_ms":19062,"reading_group":"no","serious_thinker":"yes","would_accept_peer_review":false},"rs_alignment":null,"lean_confirmation":null,"pith_extraction":{"msc":[],"pacs":[],"model":"deepseek-v4-flash","headline":"The organisers of a workshop on central exclusive production at the LHC conclude that measuring both outgoing protons and the full central final state is the key to studying pomeron couplings, isolating photon exchange, and hunting for…","keywords":["central exclusive production","odderon","glueball","pomeron","reggeon","photon exchange","forward proton tagging","LHC diffraction"],"falsifier":"A decisive check would be a high-statistics LHC run with forward proton tagging at small $|t|$ and full particle identification, searching for CEP signals. If, with these capabilities, no odderon-sensitive asymmetry or glueball-filter enhancement appears above backgrounds, or if it is demonstrated that the required forward coverage cannot be reached, the workshop's central conclusion would be undercut.","tokens_in":4502,"feed_emoji":"⚛️","tokens_out":9380,"duration_ms":80039,"temperature":0.7,"pith_summary":"This report from the organisers of an LHC workshop on central exclusive production (CEP) argues that the reaction p + p -> p + X + p, with both protons surviving and large rapidity gaps, is a promising route to three non-perturbative QCD questions: how the pomeron, odderon, reggeons, and photon couple to protons and to the central system X, where odderon effects can first be seen, and what hadronic systems X can be produced. The organisers' bottom line is that CEP offers excellent possibilities for odderon searches and that the search for and characterisation of glueballs are prime topics. They stress that these studies will pay off only if the complete final state can be measured, including the transverse momenta of both outgoing protons and particle identification of the central system. Without such measurements, photon exchange cannot be isolated from odderon backgrounds, and reggeon contributions at pseudorapidities up to about 4 to 5 would be missed.","feed_headline":"Both protons measured: the LHC route to the odderon","feed_subtitle":"Workshop report says full final-state detection and particle ID can isolate photon exchange and expose glueballs.","key_machinery":"The central object is the exclusive reaction $p + p \\to p + X + p$ with large rapidity gaps between the surviving protons and the central system $X$, produced by exchange of the pomeron, the odderon, the reggeons, or the photon. The argument is carried by two theoretical tools: an effective model in which charge-conjugation-even exchanges couple as second-rank symmetric tensors while charge-conjugation-odd exchanges couple as vectors, and a resonance ansatz that correlates the production rates of many states lying on a common exchange trajectory. On the experimental side, the load-bearing observable is the pair of proton transverse momenta: their difference defines the glueball-filter variable, their azimuthal angle enters the pomeron-pomeron-$X$ couplings, and their small values isolate photon exchange. Absorption corrections (eikonal and Sudakov suppression) are the main known obstacle, reducing Born-level cross sections by factors of order ten or more.","core_discovery":"The organisers' central claim is that central exclusive production at the LHC is a clean and promising arena for non-perturbative QCD. Their conclusions are that CEP allows a detailed study of pomeron couplings, offers excellent possibilities to look for odderon-exchange effects (with great experimental effort required), and offers many opportunities to study hadronic resonances, with glueball search and characterisation as prime topics. They further conclude that these studies benefit considerably if the complete final state can be measured and particle identification is available, because the transverse momenta of the outgoing protons determine the azimuthal angle $\\phi_{pp}$ and the glueball-filter variable, and small $|t|$ coverage is needed to isolate photon exchange from odderon backgrounds.","pith_inferences":["A natural next step would be to use photon-exchange CEP in proton-nucleus collisions as a calibration or luminosity channel, since the photon flux differs strongly between proton and nuclear beams but the central system is produced by the same mechanism.","The glueball-filter variable could be tested on existing diffractive data before dedicated forward detectors are upgraded, providing an early check of the filter's discriminating power.","If full final-state measurement is achieved, the same exclusive topology could yield relatively model-independent pomeron couplings by comparing pp, Ap, and AA data, a comparison the report lists as possible but does not develop."],"forward_implications":["Measuring the transverse momenta of both outgoing protons determines the azimuthal angle $\\phi_{pp}$, needed to pin down the pomeron-pomeron-$X$ couplings.","The glueball-filter variable, the magnitude of the difference of the two proton transverse momenta, is a proposed handle for identifying glueballs in CEP.","Particle identification of the central system's decay products would characterise glueball candidates by their flavour composition.","Reaching small $|t|$ for forward protons is required to isolate photon-exchange CEP and to separate the competing photon background in odderon searches.","Reggeon contributions, though small at central pseudorapidities, become non-negligible for $|\\eta|$ up to about 4 to 5, so wide forward coverage is needed."],"supporting_citations":[{"why":"Frames the reaction and summarises the experimental context of central exclusive particle production.","marker":"[1]"},{"why":"Supplies the effective tensor-pomeron and vector-odderon exchange model used in the workshop discussions.","marker":"[2]"},{"why":"Applies that exchange model to central exclusive scalar and pseudoscalar meson production.","marker":"[3]"},{"why":"Models resonance production in pomeron-pomeron collisions with a resonance ansatz correlating states on a common trajectory.","marker":"[7]"},{"why":"Gives holographic predictions for scalar glueball decay channels that could be tested in CEP.","marker":"[10]"},{"why":"Quantifies eikonal and Sudakov absorption, the suppression that must be controlled in odderon searches.","marker":"[19]"},{"why":"Proposes the glueball-anti-quark filter variable used for glueball identification.","marker":"[24]"}],"fun_headline_variants":["LHC workshop: complete final state for odderon search","Exclusive production: measuring both protons exposes glueballs","Central exclusive production: a clean QCD probe at LHC","Odderon and glueball search via full final-state detection","Full final-state detection for odderon and glueball search"],"cache_read_input_tokens":3200,"weakest_assumption_plain":"The programme assumes that LHC experiments can measure the outgoing protons at very small transverse momentum (small $|t|$), cover pseudorapidities up to about 4 to 5, and identify the central final-state particles; if they cannot, photon exchange cannot be isolated and odderon effects cannot be separated from backgrounds.","fun_headline_variants_meta":{"raw":{"variants":["LHC workshop: complete final state for odderon search","Exclusive production: measuring both protons exposes glueballs","Central exclusive production: a clean QCD probe at LHC","Odderon and glueball search via full final-state detection","Full final-state detection for odderon and glueball search"]},"model":"deepseek-v4-flash","effort":"low","cost_usd":0.001258,"raw_usage":{"total_tokens":5046,"prompt_tokens":733,"completion_tokens":4313,"prompt_tokens_details":{"cached_tokens":384},"prompt_cache_hit_tokens":384,"prompt_cache_miss_tokens":349,"completion_tokens_details":{"reasoning_tokens":4229}},"tokens_in":349,"tokens_out":4313,"duration_ms":28951,"temperature":1.0,"reasoning_tokens":4229,"cache_read_input_tokens":384,"cache_creation_input_tokens":0},"cache_creation_input_tokens":0},"created_at":"2026-08-14T10:05:32.353889+00:00","model_set":{"reader":"deepseek-v4-flash"},"falsifier":"A decisive check would be a high-statistics LHC run with forward proton tagging at small $|t|$ and full particle identification, searching for CEP signals. If, with these capabilities, no odderon-sensitive asymmetry or glueball-filter enhancement appears above backgrounds, or if it is demonstrated that the required forward coverage cannot be reached, the workshop's central conclusion would be undercut.","supporting_citations":[{"cited_title":"Resonance production in Pomeron-Pomeron collisions at the LHC","cited_arxiv_id":"1512.04977","evidence_quote":"Models resonance production in pomeron-pomeron collisions with a resonance ansatz correlating states on a common trajectory."},{"cited_title":"Nonchiral enhancement of scalar glueball decay in the Witten-Sakai-Sugimoto model","cited_arxiv_id":"1504.05815","evidence_quote":"Gives holographic predictions for scalar glueball decay channels that could be tested in CEP."}],"review_version":1}