{"id":"43a3706d-1df8-4a42-bc80-89a7fed8e28c","arxiv_id":"2411.15017","paper_version":1,"verdict":"CONDITIONAL","confidence":"MODERATE","novelty_score":3.0,"correctness_risk":"medium","formal_verification":"none","parameter_count":0,"one_line_summary":"Heavy-quark elliptic-flow measurements show charm and beauty thermalize differently in Pb-Pb, significant muon flow in p-Pb, and no J/psi flow in high-multiplicity pp.","lead":"This conference paper summarizes ALICE measurements of heavy-quark flow in proton-proton, proton-lead, and lead-lead collisions, showing that beauty quarks thermalize less than charm quarks and that J/psi flow is nonzero in p-Pb but consistent with zero in pp. The measurements provide new constraints on models of the quark-gluon plasma and on collective behavior in small collision systems.","discovery_kind":"extension","skeptic_critique":{"model":"deepseek-v4-flash","headline":"The pp J/psi v2 'consistent with zero' claim is the paper's central new physics conclusion, but the manuscript shows no data, no uncertainties, and no method for that measurement, so the 1-sigma statement is not independently checkable.","rationale":"The reader's weakest_assumption focuses on non-flow subtraction and event-plane bias in the p-Pb muon v2 and J/psi v2 comparisons. That is a real methodological concern, but for a proceedings paper the more precise problem is that the paper's central new conclusion about pp J/psi v2 being consistent with zero is made without showing the underlying distribution or uncertainties, so it is not independently checkable. The reader's rationale identifies the same paper as CONDITIONAL due to insufficient documentation and reference errors; I agree with that verdict but locate the load-bearing weakness differently: not in a generic non-flow assumption, but in the absence of any reported statistical and systematic uncertainties for the pp J/psi v2 result, which is the paper's most significant physics interpretation and the one that is not a quote from a published ALICE paper. The reference list errors (e.g., Refs. [1]-[3] all pointing to the same arXiv number, Ref. [8] citing a 2015 paper about pA heavy quarkonia as a CGC model for inclusive muon flow in p-Pb) are real but secondary. The claim that beauty quarks thermalize less than charm is well supported by the cited published analyses (Refs. [3,4]) and not a concern here. The signal extraction in Fig. 4 is explicitly an exploratory 'fit ... showing the extracted signals' with no yield/uncertainty reported, so it is not load-bearing for the physics conclusions. Therefore, the condition for acceptance should be: either the pp J/psi v2 data must be shown with uncertainties, or the claim must be rephrased as a reference to the underlying ALICE analysis rather than as a new statement. The verdict remains CONDITIONAL, with the condition being the verification of the pp J/psi v2 zero result.","tokens_in":4621,"tokens_out":1689,"duration_ms":14500,"concrete_test":"Request the pp J/psi v2 figure with data points and total uncertainties from the author (or obtain the preliminary ALICE analysis note), and verify whether the pT-integrated v2 in 1 < pT < 12 GeV/c is indeed within 1 sigma of zero. If the central value and uncertainty satisfy this, the claim is supported; if the figure shows a 1-2 sigma deviation that was not propagated, the conclusion would need to be softened.","verdict_should_be":"CONDITIONAL","load_bearing_attack":"The strongest new physics claim in this proceedings is the statement that J/psi v2 in high-multiplicity pp collisions is consistent with zero within 1 sigma, including for the integrated pT range 1-12 GeV/c, and that this indicates absence of significant collective behavior for J/psi in small systems. This is an interpretation claim, not just a numerical statement, and it is the only measurement presented in the paper that is not a reference to a published ALICE analysis. The full text does not show the pp J/psi v2 data points, the analysis method, the non-flow subtraction used, or the systematic uncertainties. The only context is a figure (Fig. 3) that is not included in the text, and a sentence saying the measurement was obtained using azimuthal correlations between inclusive dimuons and charged hadrons in high-multiplicity pp collisions. Without the actual distribution and its uncertainties, the 1 sigma statement cannot be checked. The reader's verdict is CONDITIONAL because the paper is a proceedings with new preliminary signal extraction, but the load-bearing issue is that the pp J/psi v2 result is the one piece of new physics interpretation that is both central to the conclusion 'no collective behavior for J/psi in small systems' and entirely unsupported in the manuscript text.","agreement_with_reader":"partial"},"referee_report":{"model":"deepseek-v4-flash","summary":"This proceedings contribution by the ALICE collaboration summarizes recent elliptic-flow (v2) measurements for heavy-flavor particles in pp, p-Pb, and Pb-Pb collisions. It reports (i) a comparison of non-prompt D0-meson v2 with prompt non-strange D-meson v2 in Pb-Pb at 5.02 TeV, (ii) inclusive muon v2 in high-multiplicity p-Pb at 8.16 TeV, (iii) J/psi v2 in pp, p-Pb, and Pb-Pb systems, and (iv) preliminary Run 3 signal extraction for inclusive J/psi at mid and forward rapidity. The main new physics statement is that J/psi v2 in high-multiplicity pp collisions is consistent with zero within 1 sigma, which is interpreted as an absence of significant collective behavior for J/psi in small systems.","tokens_in":4882,"tokens_out":3542,"duration_ms":36075,"significance":"If the results hold, the reported 3.2-sigma difference between non-prompt D0 and prompt D meson v2 in Pb-Pb provides a direct constraint on charm and beauty thermalization in the quark-gluon plasma, and the near-zero J/psi v2 in high-multiplicity pp collisions is an important discriminator between initial-state and final-state explanations of small-system collectivity. The paper's strengths are that most measurements are drawn from published ALICE analyses with explicit references, the model comparisons are clearly labeled as external, and the Run 3 signal extraction is presented as preliminary. However, the pp J/psi v2 result, which carries the strongest new interpretive claim, is not documented in the text, preventing independent checking of the central conclusion.","major_comments":[{"comment":"The statement that J/psi v2 in high-multiplicity pp collisions is consistent with zero within 1 sigma, both as a function of pT and integrated over 1 <= pT <= 12 GeV/c, is the paper's only new physics conclusion not backed by a published ALICE analysis. The text gives no data points, no statistical or systematic uncertainties, and no description of the analysis method beyond one sentence on azimuthal correlations between inclusive dimuons and charged hadrons. The numerical content of Fig. 3 is not present in the manuscript text, and no public ALICE preliminary note is cited. Please provide a table of the v2 values with full uncertainties and a clear statement of the non-flow treatment, or cite a public preliminary result; without this, the claim cannot be checked.","section":"Results, Fig. 3 and following paragraph"},{"comment":"The inclusive muon v2 measurement in p-Pb is described as having non-flow effects subtracted and as using two-particle correlations, but neither the subtraction procedure nor the systematic uncertainties are defined in the text. The interpretation that heavy quarks exhibit significant flow at mid-to-high pT depends on this subtraction. Since Ref. [9] is cited for the method, the figure caption and text should explicitly state that the result is a published ALICE measurement and point to the details in that reference, rather than describing it as a standalone new analysis.","section":"Results, Fig. 2 and caption"}],"minor_comments":[{"comment":"Several references have broken DOIs: Refs. [1], [2], [3], [5], [6], [7], [8], [9], [10], and [11] all resolve to arXiv:2307.14084, which is not the cited article. The reference list should be corrected before publication.","section":"References [1]-[12]"},{"comment":"There is a typo in the phrase 'compared with theorical models'; it should read 'theoretical models'.","section":"Introduction"},{"comment":"The comparison with the LIDO model is presented qualitatively. For a proceedings this is acceptable, but a sentence on the uncertainty bands of the model predictions would help the reader assess the degree of agreement.","section":"Results, Fig. 1"},{"comment":"The summary states that Run 3 data 'will enable' more precise measurements immediately after presenting Run 3 signal extraction; consider rewording to clarify which quantities are preliminary and which are projections.","section":"Summary"}],"recommendation":"major_revision","confidential_remarks":"The paper is a proceedings summary and most of its content is a review of published ALICE results, which is appropriate for the venue. The central issue is the unsupported pp J/psi v2 claim: it is stated as a new 1-sigma result but the manuscript contains no numerical evidence or method details. This is fixable by adding a small table or by citing a public ALICE preliminary note. The broken DOIs suggest the reference list was assembled hastily and should be checked by the editor. If the journal's proceedings policy allows, the authors might also be asked to mark all results that are not from refereed publications as preliminary in both the text and figure captions."},"author_rebuttal":null,"desk_editor":{"model":"deepseek-v4-flash","letter":"Quick take: this is a conference proceedings that recaps already-published ALICE flow measurements and adds a preliminary Run 3 signal extraction. The main thing you should know: the paper's most cited conclusion—that J/psi v2 in high-multiplicity pp is consistent with zero within 1 sigma and thus no collective behavior—appears nowhere in the data shown. There is no figure, no table, no systematic uncertainty, and no reference to a dedicated ALICE paper for that measurement. If you cite this work for that claim, you'd be relying on a sentence.\n\nWhat's good: the summary of published results is accurate. The comparison between prompt and non-prompt D0 v2 with 3.2 sigma is correctly attributed to Ref [3], and the LIDO model discussion is fair. The p-Pb inclusive muon v2 measurement over 0.5–10 GeV/c is genuinely new as a proceedings figure, and the comparison with AMPT and CGC is useful. The Run 3 signal extraction fits in Fig. 4 are a reasonable status update, though they don't yet constitute a physics result.\n\nSoft spots: the reference list is in a bad state—several DOIs resolve to the same generic arXiv link (2307.14084), and refs [3], [4], [9] have wrong DOIs. That's sloppy and undermines the paper's utility as an entry point. The multiparticle cumulant method is mentioned but no v2 values are shown, so it's a placeholder. The pp J/psi v2 claim is the real issue: it's the only new physics statement that is not a restatement of a published analysis, and it lacks all supporting evidence. The stress-test note is right about that.\n\nBottom line: for a PoS proceedings, this is acceptable as a status report, but if it were a journal submission I'd want either a proper reference to the underlying measurement or removal of the pp claim. A serious referee could easily check whether the claim is supported and whether the references are fixed.\n\nRecommendation: I'd send it to peer review only if the venue wants proceedings verified; otherwise it's a marginal contribution. Engaging with it is fine for a reading group on how collaboration summaries can overclaim.","headline":"A solid ALICE proceedings summary whose one new physics claim—'no J/psi flow in pp'—is unsupported in the text; the rest is a competent recap of published results.","tokens_in":5374,"tokens_out":2364,"would_cite":false,"duration_ms":23151,"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":"ALICE reports that in Pb-Pb collisions the elliptic flow of non-prompt D0 mesons from beauty decays is lower than that of prompt D mesons by 3.2 standard deviations, indicating charm and beauty quarks thermalize differently in the…","keywords":["elliptic flow","heavy quarks","quark-gluon plasma","charmonium","D mesons","beauty quarks","small collision systems","ALICE"],"falsifier":"Compute the same $v_2$ signals with four-particle cumulants in high-multiplicity p–Pb and pp collisions at $p_T > 2$ GeV/$c$; if the four-particle value is consistent with zero while the two-particle value is not, the two-particle flow is dominated by non-flow contamination and the collective-flow interpretation weakens.","tokens_in":4449,"feed_emoji":"🌀","tokens_out":13483,"duration_ms":118617,"temperature":0.7,"pith_summary":"This contribution uses the azimuthal anisotropy of heavy-flavor particles to probe how strongly charm and beauty quarks couple to the quark-gluon plasma. In 30–50% central Pb–Pb collisions, the elliptic flow $v_2$ of non-prompt $D^0$ mesons from beauty decays sits below the flow of prompt charm mesons by 3.2 standard deviations for $2 < p_T < 8$ GeV/$c$, a difference the authors read as different degrees of thermalization. In high-multiplicity p–Pb collisions, inclusive muons from heavy-flavor decays show an elliptic flow peaking near $p_T = 2$ GeV/$c$, indicating that heavy quarks participate in collective motion in small systems. In high-multiplicity pp collisions, the $J/\\psi$ $v_2$ is consistent with zero within 1 standard deviation, so no collective behavior is observed for charmonia there. Together these results tighten constraints on heavy-quark transport models and on whether QGP-like flow develops in small collision systems.","feed_headline":"Beauty quarks flow less than charm in quark-gluon plasma","feed_subtitle":"A 3.2-sigma gap between non-prompt D0 and prompt D-meson flow signals unequal thermalization in the QGP.","key_machinery":"The central observable is the elliptic flow coefficient $v_2$, the second Fourier harmonic of the azimuthal angle distribution of emitted particles, extracted with event-plane, two-particle correlation, scalar-product, and multiparticle-cumulant methods. The prompt/non-prompt separation uses the displaced decay vertex of $D^0$ mesons, so charm decays can be distinguished from beauty decays and the same coefficient can be compared across the two sectors. At forward rapidity, inclusive-muon and $J/\\psi$ flow are obtained from dimuon/charged-hadron azimuthal correlations with non-flow contributions subtracted. The comparison with LIDO, AMPT, CGC, and TAMU calculations is what converts measured coefficients into statements about thermalization, energy loss, and charmonium regeneration.","core_discovery":"On its own terms, the paper reports that ALICE measures the elliptic flow $v_2$ of prompt $D$, $D^+$, and $D^{*+}$ mesons and of non-prompt $D^0$ mesons in 30–50% central Pb–Pb collisions at 5.02 TeV. The non-prompt (beauty-decay) $v_2$ is lower than the prompt charm-meson $v_2$ by 3.2 standard deviations for $2 < p_T < 8$ GeV/$c$, and its weighted mean over $2 < p_T < 12$ GeV/$c$ is 2.7 standard deviations above zero; the LIDO transport model reproduces both the non-prompt $D^0$ and the beauty-decay-electron $v_2$. At forward rapidity in high-multiplicity p–Pb collisions at 8.16 TeV, inclusive muons from heavy-flavor decays show a $v_2$ that rises to about 0.07 near $p_T = 2$ GeV/$c$ and remains nonzero out to 10 GeV/$c$, with AMPT and CGC models describing the data. For $J/\\psi$, the $v_2$ measured in high-multiplicity pp collisions is consistent with zero within 1 standard deviation over $1 < p_T < 12$ GeV/$c$, while in p–Pb it approaches the Pb–Pb values for $p_T > 4$ GeV/$c$, an observation the TAMU transport model reads as energy loss plus low-$p_T$ regeneration. The stated conclusion is that charm and beauty thermalize to different extents in the QGP, heavy quarks flow in p–Pb, and charmonia show no detectable collective flow in pp at current precision.","pith_inferences":["A natural extension would be to measure fully reconstructed $B$ mesons and compare their $v_2$ with non-prompt $D^0$ mesons, testing whether decay kinematics really are as negligible as the LIDO comparison assumes.","If the $J/\\psi$ $v_2$ stays zero in pp while open-charm hadron $v_2$ in the same high-multiplicity pp events is nonzero, that would point to mass or color-charge effects in how small-system collectivity couples to heavy quarks; the present paper does not make that comparison.","A cross-check of the p–Pb inclusive-muon $v_2$ with four-particle cumulants would separate true collectivity from non-flow; if it vanishes, the heavy-quark-flow-in-small-systems conclusion would need revision.","The contrast between zero $J/\\psi$ $v_2$ in pp and nonzero values in p–Pb suggests the collectivity in p–Pb may depend on the nuclear target rather than on multiplicity alone, a prediction that could be tested in high-multiplicity pp events at matched charged-particle multiplicity."],"forward_implications":["If the 3.2-standard-deviation gap is real, transport models must treat charm and beauty as separately thermalizing species, and the beauty-quark spatial diffusion coefficient can be extracted from non-prompt $D^0$ and $B$-meson $v_2$.","The 2.7-standard-deviation nonzero non-prompt $D^0$ $v_2$ implies that beauty quarks do join the collective flow, just less strongly than charm quarks.","A $J/\\psi$ $v_2$ consistent with zero in high-multiplicity pp means there is no evidence for charmonium collectivity in pp at current precision.","The nonzero inclusive-muon $v_2$ for $p_T > 2$ GeV/$c$ in p–Pb, where heavy-flavor decays dominate, indicates heavy quarks flow in small systems and constrains initial-state versus final-state explanations.","The new four-particle cumulant extraction on Run 3 data should reduce non-flow contamination and settle whether the pp $J/\\psi$ $v_2$ is genuinely zero or merely small."],"supporting_citations":[{"why":"Provides the non-prompt D0-meson elliptic flow measurement in Pb-Pb that is the key evidence for a charm-beauty thermalization difference.","marker":"[3]"},{"why":"Supplies the v2 of electrons from beauty-hadron decays used as a second beauty-sector measurement.","marker":"[4]"},{"why":"Defines the LIDO transport model used to describe non-prompt D0 and beauty-electron flow.","marker":"[5]"},{"why":"Provides the AMPT model comparison for the p-Pb inclusive-muon v2 data.","marker":"[7]"},{"why":"Provides the color-glass-condensate model comparison for the p-Pb inclusive-muon v2 data.","marker":"[8]"},{"why":"Establishes the two-particle correlation method used for the p-Pb inclusive-muon v2 measurement.","marker":"[9]"},{"why":"Supplies the p-Pb J/psi v2 data compared with pp and Pb-Pb measurements.","marker":"[10]"},{"why":"Supplies the Pb-Pb J/psi v2 reference used to show similarity with p-Pb at high pT.","marker":"[11]"},{"why":"Provides the TAMU transport-model interpretation of J/psi v2 through energy loss and regeneration.","marker":"[12]"}],"fun_headline_variants":["Charm and beauty flow at different rates in QGP","Beauty quarks move slower than charm in heavy-ion collisions","Unequal thermalization: charm flows more than beauty","ALICE measures a 3.2-sigma gap in heavy-quark flow","Heavy-quark flow splits by flavor in QGP"],"cache_read_input_tokens":3200,"weakest_assumption_plain":"The interpretation rests on assuming the measured azimuthal patterns are true collective motion, with leftover jet correlations, resonance decays, and detector effects fully removed by the correlation and event-plane methods.","fun_headline_variants_meta":{"raw":{"variants":["Charm and beauty flow at different rates in QGP","Beauty quarks move slower than charm in heavy-ion collisions","Unequal thermalization: charm flows more than beauty","ALICE measures a 3.2-sigma gap in heavy-quark flow","Heavy-quark flow splits by flavor in QGP"]},"model":"deepseek-v4-flash","effort":"low","cost_usd":0.000264,"raw_usage":{"total_tokens":1695,"prompt_tokens":1126,"completion_tokens":569,"prompt_tokens_details":{"cached_tokens":384},"prompt_cache_hit_tokens":384,"prompt_cache_miss_tokens":742,"completion_tokens_details":{"reasoning_tokens":483}},"tokens_in":742,"tokens_out":569,"duration_ms":6045,"temperature":1.0,"reasoning_tokens":483,"cache_read_input_tokens":384,"cache_creation_input_tokens":0},"cache_creation_input_tokens":0},"created_at":"2026-08-12T14:35:50.300490+00:00","model_set":{"reader":"deepseek-v4-flash"},"falsifier":"Compute the same $v_2$ signals with four-particle cumulants in high-multiplicity p–Pb and pp collisions at $p_T > 2$ GeV/$c$; if the four-particle value is consistent with zero while the two-particle value is not, the two-particle flow is dominated by non-flow contamination and the collective-flow interpretation weakens.","supporting_citations":[{"cited_title":"Elliptic flow of electrons from beauty-hadron decays in Pb-Pb collisions at $\\sqrt{s_{\\rm NN}}$ = 5.02 TeV","cited_arxiv_id":"2005.11130","evidence_quote":"Supplies the v2 of electrons from beauty-hadron decays used as a second beauty-sector measurement."}],"review_version":1}