{"id":"0a8f6a04-67db-4ba6-bc5e-73ca31b6edfe","arxiv_id":"2505.08738","paper_version":1,"verdict":"UNVERDICTED","confidence":"MODERATE","novelty_score":0.0,"correctness_risk":"medium","formal_verification":"none","parameter_count":4,"one_line_summary":"A review of Run-2 leptoquark searches at ATLAS and CMS, highlighting three new analyses and stating that no leptoquark signal has been observed; no new physics results are presented.","lead":"This conference proceedings paper summarizes recent ATLAS and CMS searches for leptoquarks, hypothetical particles that couple quarks and leptons. It reports no new experimental results and no observed signal, while collecting the latest exclusion limits on leptoquark mass and couplings.","discovery_kind":"review","skeptic_critique":{"model":"deepseek-v4-flash","headline":"No significant objection identified","rationale":"The reader's weakest assumption concerns the simplified benchmark models used in LHC searches. I agree this is a real limitation of the physics reach, but it is not a load-bearing threat to this paper's central claim. The paper explicitly states that searches use simplified models with parameters (mLQ, λ, β, κ), and the conclusion is framed in terms of those benchmarks. A review can accurately report benchmark-dependent exclusions without claiming model-independent coverage. The central claim is a summary of external ATLAS/CMS results; there is no new derivation, fit, or simulation to critique. I checked for internal inconsistencies: the headline numbers (0.9/1.5 TeV in the ccνν search, beyond 5 TeV in the nonresonant search, 3 TeV in the ditau search) are consistent with the cited figures and text. The only concrete defect is a typo in the β bullet list in Section 2, which is cosmetic. I therefore see no reason to change the reader's UNVERDICTED verdict; the paper is a review whose correctness depends on faithful representation of external results, but nothing in the text suggests a misrepresentation that would undermine the central claim.","tokens_in":6208,"tokens_out":4894,"duration_ms":49305,"concrete_test":"Spot-check the numerical limits quoted in Section 3 against the collaboration papers: verify that CMS-EXO-22-013 (Ref. 12) supports the \"beyond 5 TeV at large couplings\" statement for at least one benchmark, and that ATLAS EXOT-2022-42 (Ref. 13) supports the mLQ > 3 TeV limit at λ > 2.4. If these contours do not match the quoted numbers, the summary would need revision.","verdict_should_be":"UNCHANGED","load_bearing_attack":"No significant objection identified. This paper is a conference proceedings review; its central claim is a summary of public ATLAS and CMS Run-2 results. The strongest claim—no observed LQ signal, with pair-production exclusions around 2 TeV and nonresonant exclusions beyond 5 TeV at high coupling—stands or falls with the cited papers (Refs. 11–13), not with any new derivation in this note. The text consistently frames exclusions as benchmark-dependent (simplified models with mLQ, λ, β, κ), so simplified-model coverage is an explicit caveat rather than a hidden assumption. The only internal issue I see is a minor typo in Section 2: the bullet list says \"β = 1 (a mix)\", which should presumably read \"0 < β < 1\". This does not affect the conclusion. The review's numbers are plausible and traceable to the cited searches, and I cannot identify a load-bearing internal inconsistency or unsupported step.","agreement_with_reader":"partial"},"referee_report":{"model":"deepseek-v4-flash","summary":"This paper is a conference proceedings overview of Run-2 leptoquark (LQ) searches by ATLAS and CMS at sqrt(s)=13 TeV with 137-140 fb^-1 of data. It introduces the simplified-model parameters used in LHC searches (mLQ, lambda, beta, kappa), catalogs pair-production, single-production, and nonresonant t-channel dilepton searches in Tables 1-4, and highlights three recent results: the ATLAS search for LQ pair production decaying to cc nu nu, excluding scalar (vector) LQ masses up to 0.9 (1.5) TeV; the CMS nonresonant dielectron/dimuon search setting exclusion limits up to about 5 TeV at large couplings; and the ATLAS nonresonant ditau search excluding mLQ > 3 TeV for large couplings. The paper reports no significant excess and concludes that no direct evidence for leptoquarks has been observed.","tokens_in":6216,"tokens_out":6993,"duration_ms":65409,"significance":"As a proceedings summary, the paper serves a useful archival and organizational purpose: it collects the current LHC leptoquark search landscape in compact tables and directs the reader to the relevant public analyses. Its strengths are the explicit statement of simplified-model assumptions in Section 2, the coverage of recent nonresonant searches, and the traceability of the quoted limits to Refs. 11-13. The paper makes no new derivation and does not re-analyze data, which is appropriate for this format. The stress-test concern that real leptoquarks might not be captured by the simplified benchmark models is explicitly acknowledged in Section 2, so it does not undermine the paper's claims; the reported exclusions are correctly framed as benchmark-dependent.","major_comments":[],"minor_comments":[{"comment":"In the benchmark bullet list, the entry 'beta = 1 (a mix)' should read '0 < beta < 1 (a mix)'; as written, the same value beta = 1 is assigned to both the no-neutrino and mixed scenarios.","section":"Section 2 (bullet list)"},{"comment":"The sentence 'Although that search could distinguish between jet flavors of a potential signal, it set more stringent exclusion limits' appears to be missing a negation: since the CMS search in Ref. 14 did not exploit charm tagging, the intended meaning is likely 'could not distinguish between jet flavors.'","section":"Section 3.1"},{"comment":"The phrase 'The LQ signal is target by selecting events' should be 'The LQ signal is targeted by selecting events.'","section":"Section 3.1"},{"comment":"The phrase 'contribute most at in the high-m_ll tail' contains an extra 'at'; it should read 'contribute most in the high-m_ll tail.'","section":"Section 3.2"},{"comment":"The note 'Ref. 8 is currently only search the photon-induced single production' should be rephrased, for example 'Ref. 8 currently searches only for photon-induced single production.'","section":"Section 2"},{"comment":"The conclusion's claim that pair-production searches reach 'up to about 2 TeV or beyond' is not explicitly tied to a specific cited result in the text; please add a reference to Refs. 9/10 or to a representative pair-production search.","section":"Section 4"},{"comment":"The sentence 'An overview of searches for leptoquarks in proton-proton collisions at ATLAS and CMS are presented' has a subject-verb agreement error; it should be 'is presented.'","section":"Abstract"},{"comment":"The title in the manuscript header contains a spacing artifact, 'A TLAS'; it should read 'ATLAS.'","section":"Title/header"}],"recommendation":"minor_revision","confidential_remarks":"This is a competent and internally consistent conference proceedings summary. The numerical exclusions quoted in the text agree with the cited public analyses as far as I can verify, and the paper explicitly acknowledges the simplified-model dependence of the reported limits. The requested changes are limited to typographical and minor clarity fixes; no load-bearing technical issue was identified."},"author_rebuttal":null,"desk_editor":{"model":"deepseek-v4-flash","letter":"Lena,\n\nThis is a conference proceedings review, not a research paper. It claims nothing new: it summarizes published ATLAS and CMS Run-2 leptoquark searches, highlights three recent analyses (one of which, the nonresonant ditau search, is presented for the first time at this conference), and packages the field into convenient tables. If you need a quick orientation to current LQ bounds, this is a fine place to start.\n\nWhat the paper does well is the organizational work. Tables 1–4 map searches by production mode and final state in a way I haven't seen collected elsewhere, and the highlight sections are faithful to the original papers. The caveat that exclusions depend on simplified-model parameters (mLQ, lambda, beta, kappa) is stated up front, and the conclusion—no signal seen, pair limits around 2 TeV, nonresonant limits beyond 5 TeV at large couplings—matches the cited results. I checked the quoted numbers against the highlighted analyses as best I could from the text and they are consistent.\n\nThe soft spots are minor. There is a typo in Section 2 where the benchmark list says \"beta = 1 (a mix)\" instead of something like \"0 < beta < 1\", and the abstract has a subject-verb agreement slip. More substantively, the paper spends almost no space on single leptoquark production, giving no specific limits there, and it doesn't probe very deeply into how the simplified-model assumptions (e.g., a single LQ species, one coupling, negligible interference) affect the applicability of the limits. For a proceedings overview that is acceptable, but a reader should keep it in mind.\n\nThe stress-test note has it right: there is no load-bearing internal flaw. The review's value is as a compendium, not as a scientific advance. I would cite it as a convenient summary of the current LQ landscape, and I would send it to a referee if it were submitted to a journal—though the referee's job would be mainly to check faithfulness to the cited papers, which looks good. Bottom line: worth having on the shelf, not worth heavy scrutiny.","headline":"A competent, well-organized review of Run-2 leptoquark searches; no new physics, but a reliable map of current limits with a few minor typos.","tokens_in":6899,"tokens_out":1503,"would_cite":true,"duration_ms":17090,"reading_group":"maybe","serious_thinker":"yes","would_accept_peer_review":true},"rs_alignment":null,"lean_confirmation":null,"pith_extraction":{"msc":[],"pacs":[],"model":"deepseek-v4-flash","headline":"No leptoquark signal in Run-2: pair production excluded up to ~2 TeV, nonresonant beyond 5 TeV.","keywords":["leptoquark","ATLAS","CMS","LHC Run-2","exclusion limits","nonresonant production","pair production","lepton flavor universality"],"falsifier":"A public reanalysis of the ATLAS and CMS likelihoods with a leptoquark model containing two non-zero couplings, or the observation of a clear excess in the Run-3 versions of these searches, would directly test whether the benchmark limits are robust and whether the no-signal conclusion holds.","tokens_in":1895,"feed_emoji":"🔬","tokens_out":4210,"duration_ms":81176,"temperature":0.7,"pith_summary":"Leptoquarks are hypothetical bosons that couple a quark to a lepton and could break lepton flavor universality, making them a plausible explanation for the B-meson anomalies. This review of ATLAS and CMS Run-2 searches reports that no leptoquark signal has been seen in any covered final state, so the collaborations set exclusion limits on leptoquark mass, coupling to fermions, and branching fractions. Under simplified benchmark models, pair production is excluded up to roughly 2 TeV, while nonresonant t-channel exchange is constrained beyond 5 TeV for large couplings. A newly highlighted ditau analysis is the first in that channel to include Drell-Yan interference and begins to probe the parameter region favored by the B anomalies.","feed_headline":"Run-2 leptoquark searches exclude up to 5 TeV at high coupling","feed_subtitle":"ATLAS and CMS see no signal; pair production is excluded near 2 TeV, nonresonant channels reach past 5 TeV.","key_machinery":"The engine of these results is the simplified benchmark parametrization: each search assumes a single leptoquark mass $m_{LQ}$, one coupling $\\lambda$ (or $g$ for vector leptoquarks), a branching fraction $\\beta$ to final states with charged leptons, and for vector leptoquarks a non-minimal gluon coupling $\\kappa$, with $\\kappa = 0$ minimal and $\\kappa = 1$ Yang-Mills. On top of this, the searches exploit production-mode complementarity: pair production is QCD-driven and largely independent of $\\lambda$, single production scales as $\\lambda^2$, and nonresonant t-channel exchange scales as $\\lambda^2/m_{LQ}^4$ and becomes a pure four-fermion interaction at high mass. The recent nonresonant analyses extract signals from the shape of mass and angular distributions—bins in $m_{\\ell\\ell}$, rapidity $|y|$, the Collins-Soper angle $\\cos\\theta^*$, or $b$-jet multiplicity—using templates that include the Drell-Yan interference.","core_discovery":"The central claim is that with the full Run-2 dataset at 13 TeV, ATLAS and CMS have collectively searched the main leptoquark production mechanisms—pair production, single production, and nonresonant dilepton exchange—and find no significant deviation from the Standard Model. For each benchmark model with a single mass $m_{LQ}$, a coupling $\\lambda$, a branching fraction $\\beta$, and for vector leptoquarks a non-minimal coupling $\\kappa$, the collaborations set 95% confidence-level upper limits. Pair-produced scalar and vector leptoquarks are excluded up to approximately 2 TeV depending on the final state, and nonresonant dielectron, dimuon, and ditau searches exclude couplings above about 0.5 to 2.5 for masses up to and beyond 5 TeV. The ditau search also reports that it is now possible to begin probing the phase space favored by the B anomalies at 90% confidence.","pith_inferences":["If a real leptoquark has several non-zero couplings across generations, the single-coupling benchmark limits could be misleading; a systematic reinterpretation of the ATLAS and CMS likelihoods in multi-coupling models is the natural next step.","The template-fitting technique used for nonresonant dilepton searches, using angular distributions in rapidity and Collins-Soper angle, could be applied to other beyond-Standard-Model four-fermion interactions such as Z-prime bosons or new contact interactions.","Because the new ditau analysis is the first nonresonant search in that channel to include Drell-Yan interference, earlier limits without interference may have been slightly different, and the size of this effect could be quantified by rerunning previous fits with the interference term included.","With Run-3 luminosity, the same search strategies will either reveal a signal in the B-anomaly-favored region or exclude most of it."],"forward_implications":["If no leptoquark exists below the excluded range, explanations of the B anomalies that require light leptoquarks with large couplings are ruled out or pushed to the edge of the probed region.","Combining charged-lepton and neutrino final states lets the collaborations set limits as a function of the branching fraction beta, rather than only at beta equal to one or beta equal to zero.","At high mass, nonresonant searches behave as four-fermion interaction constraints, so their limits are largely independent of the leptoquark mass and coupling details.","The remaining uncovered final states—electrons or muons accompanied by light- or charm-flavored jets—leave room for a leptoquark that couples mainly to first- or second-generation fermions."],"supporting_citations":[{"why":"ATLAS search for LQ pair production to cc nu nu; provides pair-production exclusion up to 0.9 TeV for scalar and 1.5 TeV for vector leptoquarks.","marker":"Ref. 11"},{"why":"CMS nonresonant dielectron and dimuon search; supplies the template-reweighting method and the exclusion limits beyond 5 TeV at high coupling.","marker":"Ref. 12"},{"why":"ATLAS nonresonant ditau search; first in that channel to include Drell-Yan interference and begins probing the B-anomaly-favored region.","marker":"Ref. 13"},{"why":"CMS pair-production search without charm tagging; the baseline result that the charm-tagged search is compared against.","marker":"Ref. 14"},{"why":"ATLAS previous nonresonant ditau search; the prior result that did not fully incorporate interference.","marker":"Ref. 33"},{"why":"CMS ditau search; a current comparison result with a different coupling normalization convention.","marker":"Ref. 25"},{"why":"CMS nonresonant ditau search that also includes interference; treated as comparable to the ATLAS ditau result.","marker":"Ref. 35"},{"why":"CMS precision measurement of the forward-backward asymmetry in Drell-Yan; supplies the analytic template technique reused by the nonresonant dielectron and dimuon search.","marker":"Ref. 36"}],"fun_headline_variants":["Leptoquarks absent up to 5 TeV in Run-2","No leptoquarks: ATLAS/CMS exclude to 5 TeV","Leptoquark search: null result, 5 TeV limit","ATLAS and CMS see no leptoquarks, set 5 TeV limits","Run-2: no leptoquarks, limits to 5 TeV"],"cache_read_input_tokens":8960,"weakest_assumption_plain":"The reported limits hold only if a real leptoquark's production and decay are captured by the simplified benchmark models that assume a single leptoquark mass, one coupling to fermions, one branching fraction, and for vector leptoquarks a single non-minimal coupling; if the true particle couples across generations or interferes differently, the exclusions would not apply.","fun_headline_variants_meta":{"raw":{"variants":["Leptoquarks absent up to 5 TeV in Run-2","No leptoquarks: ATLAS/CMS exclude to 5 TeV","Leptoquark search: null result, 5 TeV limit","ATLAS and CMS see no leptoquarks, set 5 TeV limits","Run-2: no leptoquarks, limits to 5 TeV"]},"model":"deepseek-v4-flash","effort":"low","cost_usd":0.000698,"raw_usage":{"total_tokens":3080,"prompt_tokens":800,"completion_tokens":2280,"prompt_tokens_details":{"cached_tokens":384},"prompt_cache_hit_tokens":384,"prompt_cache_miss_tokens":416,"completion_tokens_details":{"reasoning_tokens":2179}},"tokens_in":416,"tokens_out":2280,"duration_ms":18383,"temperature":1.0,"reasoning_tokens":2179,"cache_read_input_tokens":384,"cache_creation_input_tokens":0},"cache_creation_input_tokens":0},"created_at":"2026-08-15T21:46:57.264698+00:00","model_set":{"reader":"deepseek-v4-flash"},"falsifier":"A public reanalysis of the ATLAS and CMS likelihoods with a leptoquark model containing two non-zero couplings, or the observation of a clear excess in the Run-3 versions of these searches, would directly test whether the benchmark limits are robust and whether the no-signal conclusion holds.","supporting_citations":[],"review_version":1}