{"id":"4786819a-0e18-4260-845e-8e6c8cd13c1f","arxiv_id":"1908.02209","paper_version":1,"verdict":"UNVERDICTED","confidence":"MODERATE","novelty_score":3.0,"correctness_risk":"medium","formal_verification":"none","parameter_count":0,"one_line_summary":"The paper reviews and summarizes the extension of qT-resummation to mixed QCD-QED corrections for Drell-Yan, reporting percent-level effects for Z production at the LHC.","lead":"This paper reviews the qT-resummation formalism for Drell-Yan production and summarizes how it is extended to include simultaneous QCD and QED radiative corrections. It reports that these mixed corrections are small but non-negligible at the percent level and help reduce theoretical uncertainties in Z boson production at the LHC.","discovery_kind":"review","skeptic_critique":{"model":"deepseek-v4-flash","headline":"The central claim inherits Ref. [20]'s factorization proof; Eq. (3.3) asserts an additive QCD+QED exponent without derivation, so any residual non-factorizable O(alpha_s alpha) term in b-space would invalidate the resummed prediction.","rationale":"The reader's weakest assumption targets the generalized factorization in impact-parameter space, Eq. (2.3) extended to QED. My concern is more specific: even if the soft-collinear factorization holds, the exponentiation structure in Eq. (3.3) must be justified order by order in the mixed coupling. The additive decomposition into G_N, pure QED terms, and mixed g'^{(n,m)} terms is asserted by analogy with the pure QCD case, and the coefficient of the first mixed term g'^{(1,1)} is not given in this paper. Because the paper is a conference proceedings and explicitly delegates the derivation to Ref. [20], it cannot by itself resolve this question; this is consistent with the reader's UNVERDICTED verdict. I therefore agree with the verdict but only partially with the stated weakest assumption, since I locate the load-bearing point in the exponent decomposition rather than in factorization as a whole. The proposed check would settle the issue by direct fixed-order comparison in b-space.","tokens_in":6072,"tokens_out":3202,"duration_ms":41388,"concrete_test":"Independently compute the b-space N-moment at O(alpha_s alpha) for q qbar -> Z, combining the eikonal real-emission contribution with one virtual gluon and one photon, and verify that all logarithmic terms are reproduced by Eq. (3.3) with the g'^{(n,m)} coefficients and hard-function expansion Eq. (3.2) of Ref. [20], leaving no non-logarithmic O(alpha_s alpha) remainder. Concretely: expand Eq. (3.1) to O(alpha_s alpha), match each logarithmic term to g'^{(1,1)} and H'^{(1,1)}; if an unmatched finite term appears, the additive exponent form in Eq. (3.3) fails and the resummed prediction is incomplete at the claimed NLL+NLO accuracy.","verdict_should_be":"UNCHANGED","load_bearing_attack":"The paper's central claim (Sec. 4) is that q_T resummation can be extended to simultaneous soft-gluon and soft-photon radiation and that the resulting mixed QCD-QED corrections to Z production are small but non-negligible. This claim rests on Eq. (3.1), written by analogy with Eq. (2.5), and on the exponent structure Eq. (3.3): G'_N is assumed to be a sum of the pure QCD exponent G_N, pure QED terms g'^{(n)}, and mixed terms g'^{(n,m)}, with the mixed running-coupling beta functions in Eqs. (3.4)-(3.5) supplying the non-trivial mixing. The weakest point is not the individual QCD or QED Sudakov factors but the assertion that there is no non-factorizable O(alpha_s alpha) remainder in b-space beyond this additive/mixed exponent. In the full theory, real soft-gluon and photon emissions factorize eikonally at leading power, but virtual-real interference and the redefinition of hard-collinear functions must be checked order by order to exclude an extra finite term that cannot be absorbed into H'_N or exp(G'_N). This paper does not perform that check; it refers to Ref. [20]. Since Fig. 1 and the 'small but non-negligible' conclusion inherit the correctness of [20], a hidden assumption in that derivation would propagate directly. This is a genuine load-bearing concern for the central claim as stated, though it is not evidence that the claim is wrong.","agreement_with_reader":"partial"},"referee_report":{"model":"deepseek-v4-flash","summary":"This paper is a proceedings contribution for LHCP 2019. It reviews the qT-resummation formalism for Drell-Yan production, surveys the state of the art in higher-order QCD corrections, and summarizes an extension of the formalism that simultaneously resums soft-gluon and soft-photon radiation. The central new content is in Sec. 3.1: Eqs. (3.1)-(3.5) propose a resummed expression with a combined QCD-QED Sudakov exponent, including non-trivial mixing terms, and Fig. 1 shows NLL+NLO QED corrections to the Z-boson qT spectrum at 13 TeV. The paper concludes in Sec. 4 that these corrections are small but non-negligible, percent-level near the resummation peak, and that they reduce scale uncertainties. The technical derivation is not given in this manuscript; Ref. [20] is cited for details.","tokens_in":6386,"tokens_out":7382,"duration_ms":81531,"significance":"The paper addresses a relevant problem for precision LHC physics: mixed QCD-QED corrections to Drell-Yan production are expected to become numerically important as NNLO QCD and NLO electroweak effects compete. The proposed extension of the qT-resummation formalism is parameter-free and builds on an established factorization structure. If the underlying derivation in Ref. [20] is correct, the framework provides a tool for simultaneous resummation of gluon and photon radiation, and the phenomenological conclusion that the corrections are percent-level and stabilize scale uncertainties is valuable. The manuscript is not self-contained, and one printed equation is internally inconsistent as written; nevertheless, the claims are plausible and consistent with the cited literature.","major_comments":[{"comment":"The mixed term in the exponent is printed as a double sum over n,m starting at 1 with powers (α_S/π)^(n-2) (α/π)^(m-2). For n=m=1 this gives negative powers of both couplings, so the expansion as written is not perturbatively well-defined and does not reduce to a sensible O(α_S α) correction at the first non-trivial order. This appears to be a typo, likely the exponents should be shifted to n-1 and m-1 or equivalent, but as written it prevents the reader from verifying the claimed resummed expression. The equation should be corrected and the intended counting explained.","section":"§3.1, Eq. (3.3)"},{"comment":"The central factorization ansatz, namely that simultaneous soft-gluon and soft-photon emissions can be described by the same impact-parameter structure with the hard-collinear factor H'_N and the exponent G'_N, is introduced by analogy with Eq. (2.5) and is not derived in this paper. The text refers to Ref. [20] for details, but the conclusions in Sec. 4 depend on the absence of non-factorizable O(α_S α) remainder terms beyond the additive/mixed exponent structure. As a standalone manuscript, the central claim is therefore conditional on the correctness of the derivation in Ref. [20]. The authors should either outline the key factorization argument, at least at the level of the soft-collinear mode separation, or state explicitly that this contribution is a summary of Ref. [20] and not a self-contained new derivation.","section":"§3.1, Eqs. (3.1) and (3.3)"},{"comment":"The phenomenological claims that the QCD-QED corrections are 'percent-level close to the resummation peak' and that they 'reduce the scale uncertainties' are supported only by the figure caption and a qualitative sentence. No numerical values, central scale choices, definitions of the uncertainty bands, or input PDF/EW scheme parameters are given in the text. This makes it impossible for the reader to quantitatively assess the size of the effect or the claimed stabilization from the manuscript alone. Please include the relevant numbers or a precise pointer to the corresponding section of Ref. [20] where the inputs and definitions are fully reported.","section":"§3.1, Fig. 1 and Sec. 4"}],"minor_comments":[{"comment":"The notation c12L2 and similar terms is not defined; standard notation such as c_{1,2} L^2 or an explicit statement that the coefficients are order-dependent would improve clarity.","section":"§2, Eq. (2.2)"},{"comment":"The mixed beta functions β_{n,m} and β'_{n,m} are introduced but no explicit expressions or order-by-order values are given; at minimum, the text should state which orders enter the NLL+NLO QED result used in Fig. 1.","section":"§3.1, Eqs. (3.4)-(3.5)"},{"comment":"The caption describes left and right panels with specific features, but no figure image is visible in the text; the published proceedings version should contain the actual plot and a clear statement of its axes and units.","section":"Fig. 1"},{"comment":"There are several typographical artifacts in the text (e.g., 'V alència', 'Y an', and line-break issues in the abstract and references); a careful proofreading pass is needed before publication.","section":"General"}],"recommendation":"major_revision","confidential_remarks":"The paper is a proceedings contribution whose main technical content is already published in Ref. [20]. The self-citation is appropriate and the underlying approach appears physically sound. My main concern is that the manuscript, as written, does not stand alone at the level expected of a citable contribution: Eq. (3.3) has an algebraic inconsistency, and the key factorization step is only asserted by analogy and referred to the author's prior work. These are fixable issues, so I recommend major revision rather than rejection. The editor may also wish to confirm that the proceedings format permits such a compact summary of previously published results."},"author_rebuttal":null,"desk_editor":{"model":"deepseek-v4-flash","letter":"Dear colleague,\n\nThis is a conference proceedings write-up, not a new research paper. It summarizes work already published in JHEP 1808 (2018) 165 (Ref. [20]) on extending the qT resummation formalism for Drell-Yan to include simultaneous soft-gluon and soft-photon radiation. If you were hoping for a new derivation or a new phenomenological result, you won't find it here. What you will find is a competent and honest exposition.\n\nThe best parts are the first two sections: a compact review of the qT resummation machinery, the Sudakov form factor, the hard-collinear coefficients, and the current QCD state of the art (N3LL+NNLO). The mixed QCD-QED extension is laid out clearly in Eqs. (3.1)-(3.5), with the additive structure of the exponent and the mixed beta functions separated. Fig. 1 gives a nice summary of the phenomenological outcome—percent-level corrections near the resummation peak and reduced scale uncertainties. The author is transparent that all derivations are in Ref. [20]; this paper is explicitly a summary.\n\nThe soft spots: Eq. (3.3) asserts the exponent is a sum of pure QCD, pure QED, and mixed terms, but the factorization itself—whether soft gluons and photons can be exponentiated into a single Sudakov factor without non-factorizable O(alpha_s alpha) remainders in b-space—is not demonstrated here. That is inherited from Ref. [20]. If you have concerns about that step, you need to read the JHEP paper, not this one. Also, as a proceedings, the citation list is mostly standard plus the author's own work, which is appropriate in context.\n\nWho gets value from this? A student or colleague wanting a quick, readable map of qT resummation for Drell-Yan and where mixed QCD-QED corrections sit. It is not an advance on its own. For a proceedings volume, it is fine; as a research article, it would deserve a desk reject for lack of novelty.\n\nRecommendation: accept as proceedings, no serious referee round needed; a light consistency check against Ref. [20] would be enough.","headline":"A competent proceedings summary of the author's own prior work on mixed QCD-QED qT resummation; no new results, but a serviceable introduction.","tokens_in":6892,"tokens_out":4507,"would_cite":false,"duration_ms":45493,"reading_group":"maybe","serious_thinker":"yes","would_accept_peer_review":false},"rs_alignment":null,"lean_confirmation":null,"pith_extraction":{"msc":[],"pacs":[],"model":"deepseek-v4-flash","headline":"Transverse-momentum resummation can handle soft gluons and photons together, making mixed QCD-QED corrections to Z production computable at percent level.","keywords":["Drell-Yan","qT resummation","mixed QCD-QED corrections","Z boson production","Sudakov form factor","soft photon radiation","electroweak corrections","LHC phenomenology"],"falsifier":"Compute the mixed QCD-QED cross section at fixed order in the region $q_T \\sim M_Z$, where the resummation logarithms are small, and verify that it matches the expansion of the resummed formula; a discrepancy beyond the expected power-suppressed terms would signal a failure of the impact-parameter factorization.","tokens_in":5877,"feed_emoji":"⚛️","tokens_out":8436,"duration_ms":85072,"temperature":0.7,"pith_summary":"This paper reviews how Drell-Yan vector-boson production is computed in QCD through transverse-momentum ($q_T$) resummation, then argues that the same machinery can be extended to treat soft photon emission together with soft gluon emission. The central result presented is a resummed cross section whose Sudakov exponent contains pure QCD, pure QED, and genuinely mixed QCD-QED contributions, obtained by expanding both the hard-collinear factor and the exponent in powers of $\\alpha_S$ and $\\alpha$. Applied to Z production at the 13 TeV LHC, the framework reproduces physical results and yields NLL+NLO QED corrections, with mixing terms, that are percent-level near the resummation peak. These corrections are small but not negligible, and including them stabilizes the prediction by reducing scale uncertainties and the dependence on the electroweak scheme. A sympathetic reader would care because this is the kind of mixed correction needed to keep theoretical precision aligned with LHC data.","feed_headline":"Z production gains percent-level mixed QCD-QED corrections at the LHC","feed_subtitle":"Resumming gluon and photon radiation together shrinks the scale uncertainty of LHC Z-boson predictions.","key_machinery":"The carrying object is the extended $q_T$-resummation formula in impact-parameter space: the cross section is written as a Fourier integral over $b$ of $W_{ab}$, whose $N$-moment factorizes into a process-dependent hard-collinear factor $H'_N$ and a universal Sudakov form factor $\\exp\\{G'_N\\}$. The novelty is that $G'_N$ and $H'_N$ are double series in $\\alpha_S$ and $\\alpha$, and the two running couplings evolve with mixed $\\beta$-function coefficients $\\beta_{n,m}$ and $\\beta'_{n,m}$. This object carries the argument because it converts simultaneous soft-gluon and soft-photon emissions, which individually produce large logarithms in $q_T$, into an exponent that can be expanded order by order.","core_discovery":"The paper claims that the $q_T$-resummation formalism, originally built for QCD, extends consistently to the simultaneous resummation of soft gluon and soft photon radiation. In impact-parameter space, the Fourier-conjugate space to the transverse momentum, the $N$-moment of the resummed cross section factorizes as $(W'_{ab})_N = \\hat{\\sigma}^{(0)}_{a+b\\to F} H'_N(\\alpha_S,\\alpha) \\exp\\{G'_N(\\alpha_S,\\alpha,L)\\}$, with $H'_N$ and $G'_N$ double series in the strong and electromagnetic couplings; the exponent contains mixed $\\beta$-function terms that couple the running of $\\alpha_S$ and $\\alpha$. For Z production at the LHC, the author reports NLL+NLO QED accuracy including the non-trivial mixing terms, and the resulting $q_T$-spectrum corrections are small but non-negligible, at the percent level close to the resummation peak. The formalism is judged consistent because it gives physical predictions, and the added corrections reduce the scale uncertainty of the QCD-only result.","pith_inferences":["If the mixed exponent is universal, the same construction should appear in Higgs and diphoton $q_T$ spectra; testing it there would reveal which parts of $G'_N$ are process-independent.","The mixed beta-function coefficients in Eqs. (3.4) and (3.5) imply that QED corrections feed back into the evolution of parton densities; this could become visible in precision Drell-Yan measurements used for PDF fits.","A direct experimental check would be to extract the ratio of mixed-corrected to QCD-only predictions at several vector-boson masses: the formalism predicts how the logarithmic terms scale with $M$, so deviations would localize where the factorization breaks down."],"forward_implications":["If the extended factorization is correct, the same double-expanded Sudakov exponent can be applied to other color-singlet processes, so the machinery is not tied to Z production alone.","The QED scale variation shown in Fig. 1 provides a way to assign a combined QCD-QED theory uncertainty, which is narrower than the QCD-only band.","Adding NLL+NLO QED corrections to NNLL+NNLO QCD gives a prediction suitable for percent-level comparisons with the measured $q_T$ spectrum at 13 TeV.","The separation of $G'_N$ into QCD, QED, and mixed pieces allows each logarithmic order to be cross-checked against fixed-order mixed calculations."],"supporting_citations":[{"why":"provides the impact-parameter-space $q_T$-resummation formula (Eqs. 2.3 and 2.5) that the mixed extension starts from.","marker":"[2]"},{"why":"shows some QCD and QED channels contribute with opposite signs, enhancing the net electroweak correction and motivating the mixed treatment.","marker":"[19]"},{"why":"presents the extended QCD-QED resummation formalism and the numerical results for Z production at the LHC shown in Fig. 1.","marker":"[20]"},{"why":"supports the claim that including the mixed corrections reduces the electroweak-scheme dependence of the predictions.","marker":"[21]"}],"fun_headline_variants":["Mixed QCD-QED resummation shrinks Z-boson scale uncertainty","Simultaneous gluon and photon resummation for precise Z predictions","Percent-level QED effects in Drell-Yan from mixed resummation","New resummation framework couples QCD and QED for Drell-Yan","Tighter LHC Z-boson spectra with mixed QCD-QED resummation"],"cache_read_input_tokens":3200,"weakest_assumption_plain":"The load-bearing premise is that soft gluon and soft photon emissions factorize cleanly into one shared exponential correction in transverse-momentum space, with no leftover mixed interference terms.","fun_headline_variants_meta":{"raw":{"variants":["Mixed QCD-QED resummation shrinks Z-boson scale uncertainty","Simultaneous gluon and photon resummation for precise Z predictions","Percent-level QED effects in Drell-Yan from mixed resummation","New resummation framework couples QCD and QED for Drell-Yan","Tighter LHC Z-boson spectra with mixed QCD-QED resummation"]},"model":"deepseek-v4-flash","effort":"low","cost_usd":0.00082,"raw_usage":{"total_tokens":3562,"prompt_tokens":894,"completion_tokens":2668,"prompt_tokens_details":{"cached_tokens":384},"prompt_cache_hit_tokens":384,"prompt_cache_miss_tokens":510,"completion_tokens_details":{"reasoning_tokens":2563}},"tokens_in":510,"tokens_out":2668,"duration_ms":19705,"temperature":1.0,"reasoning_tokens":2563,"cache_read_input_tokens":384,"cache_creation_input_tokens":0},"cache_creation_input_tokens":0},"created_at":"2026-08-14T14:50:31.556028+00:00","model_set":{"reader":"deepseek-v4-flash"},"falsifier":"Compute the mixed QCD-QED cross section at fixed order in the region $q_T \\sim M_Z$, where the resummation logarithms are small, and verify that it matches the expansion of the resummed formula; a discrepancy beyond the expected power-suppressed terms would signal a failure of the impact-parameter factorization.","supporting_citations":[{"cited_title":"Combining QED and QCD transverse-momentum resummation for Z boson production at hadron colliders","cited_arxiv_id":"1805.11948","evidence_quote":"presents the extended QCD-QED resummation formalism and the numerical results for Z production at the LHC shown in Fig. 1."},{"cited_title":"Including higher-order mixed QCD-QED effects in hadronic calculations","cited_arxiv_id":"1805.06192","evidence_quote":"supports the claim that including the mixed corrections reduces the electroweak-scheme dependence of the predictions."}],"review_version":1}