{"id":"89b675f1-5267-47b8-b71c-c4ca433454fe","arxiv_id":"2505.06973","paper_version":1,"verdict":"CONDITIONAL","confidence":"MODERATE","novelty_score":3.0,"correctness_risk":"medium","formal_verification":"none","parameter_count":3,"one_line_summary":"The pT-ratio observable, a ratio of Drell-Yan event counts below and above a chosen momentum, extracts the intrinsic parton transverse momentum width qs with sensitivity comparable to fine-binned pT spectra.","lead":"This paper proposes measuring the ratio of low-momentum to high-momentum Drell-Yan lepton-pair events to learn about the internal sideways motion of quarks inside protons. The ratio avoids the need for extremely fine momentum bins and appears to be about as sensitive to the intrinsic motion as full-spectrum measurements, with smaller systematic errors.","discovery_kind":"new_method","skeptic_critique":{"model":"deepseek-v4-flash","headline":"The claimed advantage in systematics is not demonstrated: Fig. 2 compares only statistical fitting uncertainties, while the pT-ratio integrates over the high-pT region where theory uncertainties from matching and jet multiplicity enter.","rationale":"The reader's weakest assumption identifies model faithfulness and high-pT contamination as the main fragility; my reading agrees that this is the right region to probe, but I would sharpen it into a specific accounting gap: the sensitivity comparison is statistical-only, while the claimed systematic advantage is never tested against theory-systematic variations. The pT-ratio's denominator is integrated over the high-pT region, where perturbative and matching uncertainties are largest, so the observable's practical value depends on those uncertainties not dominating. The paper's own note about soft-gluon splitting moving into the upper region and the reference to higher jet multiplicities in Ref. [27] confirm that the boundary region is physically delicate. The 3% migration test is useful but addresses only one detector effect. For these reasons the central claim is plausible and the conditional verdict is appropriate, but the specific advertised benefit of lower systematics remains unquantified. A scale-variation and merging-on/off test would settle whether the ratio's sensitivity survives a more complete uncertainty budget. I therefore leave the reader's CONDITIONAL verdict unchanged and note partial agreement rather than full agreement because the reader emphasized model fidelity more broadly, whereas I see the precise missing element as the systematic-error comparison.","tokens_in":4966,"tokens_out":5882,"duration_ms":64726,"concrete_test":"Repeat the Fig. 2 sensitivity study using the same template samples but vary the renormalization and factorization scales by the conventional factors of 2 and 1/2 around the nominal choices, and repeat with and without the multi-jet merging scheme of Refs. 27-29. For each variation, refit qs from the pT-ratio and from the fine-binned spectrum at the same ps and pT,max, and compare the spread in fitted qs (a theory-systematic uncertainty) with the statistical uncertainty shown in Fig. 2. If the scale- and merging-induced spread for the pT-ratio is comparable to or larger than the statistical uncertainty, the claim of comparable sensitivity and lower systematic uncertainties is not supported.","verdict_should_be":"UNCHANGED","load_bearing_attack":"The central claim is that the pT-ratio has comparable sensitivity to the fine-binned pT spectrum and lower systematic uncertainties. The sensitivity comparison in Fig. 2 is explicitly a comparison of statistical uncertainties on the fitted qs. It shows that the two-bin ratio can be statistically competitive, but it does not quantify the systematic uncertainties that enter the ratio. In particular, the denominator p_H is the integrated yield for pT > ps, a region dominated by fixed-order hard radiation and, for ps of a few GeV, receiving significant contributions from higher jet multiplicities and from the MC@NLO matching/parton-branching scheme (Refs. 27-29). These theory uncertainties affect the denominator and therefore enter the pT-ratio directly, but they are not included in Fig. 2 and are not propagated into the extracted qs uncertainties in Fig. 3, where only statistical and scale uncertainties are shown. The 3% lepton-momentum-resolution test addresses detector migration, not PDF, scale, or matching-systematic uncertainties. Thus the paper demonstrates statistical competitiveness, not lower total uncertainty; the abstract's statement that the observable 'has lower systematic uncertainties' is asserted rather than established. The consistency check with Ref. [11] in Fig. 3 is performed with the same Monte Carlo model and the same data, so it validates internal consistency between the two observables, not the absence of model bias. Because the ratio is a single number built from the two integrated regions, any mis-modeling of the high-pT tail feeds directly into the extracted qs, and the paper does not provide a quantitative handle on this effect.","agreement_with_reader":"partial"},"referee_report":{"model":"deepseek-v4-flash","summary":"The paper proposes a two-bin 'pT-ratio' observable for Drell-Yan Z/gamma* production, defined as the ratio of event counts in p_T(lep-pair) < p_s and p_T > p_s within a coarse-grained low-p_T region, as an alternative to the fine-binned p_T spectrum for extracting the gaussian width q_s of the intrinsic transverse momentum. Using MCatNLO+CASCADE template samples generated with different q_s values, the authors compare the statistical fitting uncertainty of q_s from the pT-ratio with that from fine-binned p_T fits, including a test with 3% lepton-momentum smearing to model detector migration. They then apply the pT-ratio extraction to the CMS Drell-Yan p_T measurement and report q_s values consistent with the earlier analysis of Ref. [11]. The paper concludes that the pT-ratio has comparable sensitivity to the fine-binned spectrum and lower systematic uncertainties, and can be used directly in experiments.","tokens_in":5245,"tokens_out":6396,"duration_ms":63602,"significance":"If the central claim holds, the pT-ratio would offer a coarse-grained observable for extracting the intrinsic-kT gaussian width q_s from Drell-Yan spectra, potentially reducing the experimental burden of fine-binned measurements. The paper has concrete strengths: a Monte Carlo closure test over a range of q_s, an explicit migration study, and an external-data consistency check against the CMS measurement and Ref. [11]. The novelty lies in repackaging the low-p_T shape information into an integrated ratio and in numerically demonstrating that statistical sensitivity can survive coarse binning. The significance is, however, conditional: the claimed systematic advantage is not quantified, and the demonstration is performed entirely within one Monte Carlo framework, so the result is not yet a validated experimental methodology.","major_comments":[{"comment":"The claim that the pT-ratio observable 'has lower systematic uncertainties' is not demonstrated by the evidence presented. Fig. 2 reports only fitting uncertainties of q_s from template samples; the text does not specify that any systematic term is included, and the uncertainties appear to be statistical. The denominator p_H is the integrated yield above p_s, a region where the authors themselves note that contributions from higher jet multiplicities and the MC@NLO matching/parton-branching scheme are important (Refs. 27-29); theory uncertainties in this region enter the ratio and are not evaluated or propagated to q_s. The 3% lepton-momentum smearing test addresses detector bin-to-bin migration only, and Fig. 3 includes only statistical and scale uncertainties. Thus the paper establishes at most statistical competitiveness, not a reduction in total systematic uncertainty; the abstract should be moderated or the systematics quantified.","section":"Abstract; §'A sensitivity test...' (Fig. 2)"},{"comment":"The consistency between the pT-ratio extraction and Ref. [11] does not by itself validate the method for real data. Both this work and Ref. [11] use the same MCatNLO+CASCADE Monte Carlo model with the same parton-branching TMD input and the same CMS data, so the agreement in Fig. 3 shows internal consistency between two observables within that model, not the absence of model bias. The paper's own caveat that for too low p_s sensitivity may be lost because soft-gluon splitting transverse momenta move into the upper region indicates that the sensitivity is model-dependent. To support the claim that the pT-ratio can be applied directly in experiments, the authors should add a closure test with an alternative intrinsic-kT shape or resummation scheme, or at least quantify the model uncertainty in the extracted q_s.","section":"§'Given the difficulties...' and Fig. 3"},{"comment":"The central quantitative claim that the pT-ratio has comparable sensitivity to the fine-binned p_T shape is not self-contained: all fit details (the definition of the chi-squared, the number and statistical power of the template samples, the treatment of the non-Gaussian uncertainty of a ratio, the number of bins used for the fine-binned fit, and the procedure for the p_T-range uncertainty in Fig. 3) are deferred to Ref. [14]. Without at least a summary of these details, the reader cannot assess whether the comparison in Fig. 2 is fair or whether the error bars quoted for the pT-ratio in Figs. 2 and 3 include the expected asymmetric uncertainties of a ratio of event counts. A concise description of the fitting procedure should be included in this paper.","section":"§'A sensitivity test...' (Fig. 2) and §'Given the difficulties...' (Fig. 3)"}],"minor_comments":[{"comment":"The text contains OCR-style artifacts such as 'Ap T -ratio' and 'Drell-Y anp T'; these should be corrected.","section":"Title and first paragraph"},{"comment":"The labels 'PBset2', 'CRAPHGADM-', and 'pT-ratio of the outside plot' are garbled or unclear; the caption should fully define all curves, the inset, and the meaning of the 'outside plot' ratio.","section":"Fig. 1 caption and labels"},{"comment":"The dependence of the sensitivity on p_s is discussed only qualitatively; since the paper recommends a 'dedicated study of the separation momentum p_s', it would be useful to provide at least a heuristic criterion or a two-dimensional scan (p_s vs q_s) to guide experimental application.","section":"§'The sensitivity to the intrinsic transverse momentum...'"},{"comment":"The statement that the methodology can be applied directly to experiments assumes that acceptances, efficiencies, and backgrounds cancel in the ratio; the authors should state which experimental systematics are expected to cancel and which are not.","section":"§'Given the difficulties...'"}],"recommendation":"major_revision","confidential_remarks":"This is a short proceedings-style manuscript that summarizes the analysis of Ref. [14] (Phys. Rev. D 111, 036018). Most numerical details supporting the headline claim live in that earlier paper, and the abstract's systematic-uncertainty claim goes beyond what is shown here. The editors may wish to consider whether the manuscript is intended as a standalone research paper or as a proceedings contribution; in the former case the balance between novelty and reliance on Ref. [14] needs attention."},"author_rebuttal":null,"desk_editor":{"model":"deepseek-v4-flash","letter":"Short version: this is a conference proceedings summary of Ref. [14] (PRD 111, 036018). The pT-ratio observable is genuinely practical, and the paper explains it clearly, but every quantitative result in it is already published. If you need the idea, read Ref. [14]; if you need this paper, you want the Moriond proceedings, not a research article.\n\nWhat the paper does well: it defines a two-bin pT-ratio with a separation momentum ps, shows with MC templates that the fitted qs uncertainty from the ratio is competitive with fine-binned pT fits, and checks stability under a 3% lepton momentum resolution migration. The writing is honest about the provenance: 'based on our work published in Ref. [14]' appears in the text. The consistency with the earlier CMS-based qs extraction (Ref. [11]) is a useful sanity check.\n\nSoft spots, in proportion. The abstract's claim of 'lower systematic uncertainties' is not established here: Fig. 2 compares statistical fitting uncertainties only. The denominator p_H integrates the pT > ps region, where matching, PDF, scale, and higher-multiplicity uncertainties enter directly, and those are not propagated. The migration test is a single resolution smearing; real detector systematics involve more. The template test is a closure test using the same MC model that defines qs, so it demonstrates self-consistency rather than model independence. No code or data are shipped, so none of the numbers can be reproduced from this manuscript alone. But the paper does not pretend to be a full analysis: it delegates fit details to Ref. [14], and that is the right call for a proceedings.\n\nWho it is for: conference participants or newcomers who want a two-page overview of the observable and its first CMS-based application. Experts in TMD extraction will not find new information.\n\nRecommendation: desk reject if submitted to a research journal; accept as a proceedings contribution if that is the intended venue. A referee would only send the authors back to their own PRD paper.","headline":"Useful conference summary of an already-published pT-ratio idea; the systematics claim in the abstract outruns what the figures actually show.","tokens_in":5812,"tokens_out":2583,"would_cite":false,"duration_ms":27122,"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":"A ratio of Drell-Yan event counts below and above a separation momentum $p_s$ extracts the intrinsic transverse momentum of partons with sensitivity comparable to the full fine-binned $p_T$ spectrum, while avoiding the hardest systematic…","keywords":["p_T-ratio","intrinsic transverse momentum","Drell-Yan","TMD parton distributions","parton branching","gaussian width q_s","low-p_T spectrum"],"falsifier":"Take a dataset whose intrinsic-$k_T$ shape is known from an independent method, or generate pseudo-data with a deliberately non-gaussian intrinsic-$k_T$ distribution, then fit $q_s$ using the $p_T$-ratio for several choices of $p_s$; the proposal would fail if the fitted $q_s$ drifts with $p_s$ or disagrees with the known value while the fine-binned fit agrees.","tokens_in":4746,"feed_emoji":"⚛️","tokens_out":5163,"duration_ms":49984,"temperature":0.7,"pith_summary":"The paper proposes that the intrinsic transverse momentum of partons—the nonperturbative sideways motion of quarks and gluons inside the proton—can be extracted from Drell-Yan lepton-pair production without measuring the finely binned low-$p_T$ spectrum. Instead, one measures only the ratio of events with pair transverse momentum below a separation momentum $p_s$ to events above it. Using Monte Carlo templates, the paper argues that this $p_T$-ratio has sensitivity to the gaussian width $q_s$ of the intrinsic-$k_T$ distribution comparable to that of the full $p_T$ shape, while avoiding the delicate systematic control that fine binning demands. Applied to published collider data, the ratio-based extraction of $q_s$ across dilepton mass bins agrees with an earlier fine-binned determination. If correct, this gives experiments a cheaper, robust observable for transverse-momentum-dependent (TMD) studies.","feed_headline":"Two-bin pT ratio matches fine-binned spectra for intrinsic-kT","feed_subtitle":"Extract the proton's intrinsic transverse momentum from two coarse bins, at the same sensitivity and lower systematics.","key_machinery":"The central object is the two-bin $p_T$-ratio, $R(p_s)=p_L/p_H$. It carries the argument because the intrinsic-$k_T$ shift of the spectrum changes the two integrals in opposite directions, amplifying the effect of $q_s$; sensitivity is tuned by $p_s$, since too low a $p_s$ lets soft-gluon splitting transverse momenta fill the upper region, while too high a $p_s$ dilutes the low-$p_T$ information. The templates are generated with next-to-leading-order matrix elements matched to parton-branching TMD showers, giving next-to-leading-logarithmic accuracy in the resummation of the Drell-Yan spectrum, and the fitting procedure compares the $p_T$-ratio against these templates to extract $q_s$.","core_discovery":"In $pp\\to Z/\\gamma\\to l^+l^-$ at 13 TeV, define $p_L$ and $p_H$ as integrated event counts in the regions $p_T(ll)