{"id":"19e14092-ee8e-45e5-ad79-770c5411a7eb","arxiv_id":"2507.23471","paper_version":1,"verdict":"UNVERDICTED","confidence":"HIGH","novelty_score":0.0,"correctness_risk":"medium","formal_verification":"none","parameter_count":0,"one_line_summary":"A STAR conference proceedings summary of jet measurements in Au+Au and p+Au collisions, with all results taken from earlier STAR analyses.","lead":"This paper summarizes recent STAR measurements of charged-particle jets in 200 GeV Au+Au and p+Au collisions. It reports jet suppression in central Au+Au and a similar suppression in high-event-activity p+Au that the authors attribute to a correlation with the hard scattering scale rather than to jet quenching. All result figures are reproduced from previously published STAR papers, so the paper adds no new measurements.","discovery_kind":"review","skeptic_critique":{"model":"deepseek-v4-flash","headline":"The p+Au conclusion rests on a single-sentence validation of the saturated BBC event-activity proxy; if that proxy is biased, the anti-correlation interpretation is unsupported.","rationale":"The reader's verdict is UNVERDICTED because the manuscript is a proceedings summary; my stress test agrees with the reader's weakest_assumption and does not move the verdict. The Au+Au suppression claim is reasonably supported by the cited inclusive RAA and IAA measurements, so the central risk is isolated to the p+Au interpretation. The one-sentence validation of the BBC EA proxy in Sec. 3.3 is the weakest link: all subsequent reasoning about the absence of quenching and the EA-Q^2 anti-correlation depends on it, and the paper provides no independent confirmation. A Monte Carlo closure test or an alternative forward-activity classifier would determine whether the high/low EA selection, rather than the anti-correlation, drives the observed suppression. Because this concern affects a claim already marked unverdictable, the appropriate outcome remains UNCHANGED.","tokens_in":7337,"tokens_out":6007,"duration_ms":70682,"concrete_test":"Run a Monte Carlo closure test with the p+Au detector-response framework from Ref. [19]: generate p+Au events with PYTHIA/EPOS (no jet quenching), simulate the BBC ADC with and without the saturation correction, apply the same low/high 30% EA selection and the E_T^trig > 4 GeV BEMC trigger, and reconstruct the per-trigger trigger- and recoil-side R = 0.4 jet yields. If the MC does not reproduce the observed high/low suppression ratio, the BBC event-activity classifier is biased by saturation; if it does reproduce the ratio, the data cannot distinguish the EA-Q^2 anti-correlation from a selection artifact without additional model input.","verdict_should_be":"UNCHANGED","load_bearing_attack":"The central p+Au claim in the Conclusions — that high-EA suppression is not energy loss but a negative correlation between event activity and the hard scale Q^2 — rests entirely on the validity of the BBC Au-going ADC event-activity classifier defined in Sec. 3.3. That section acknowledges detector saturation and defends the proxy with one sentence: 'Despite detector signal saturation effects, correlations between EA measured by the BBC and midrapidity charged particle density confirm the suitability of this method.' The manuscript does not show the saturation correction, the strength of that correlation, or any demonstration that the 30% high/low EA cut is not sitting in a saturated plateau. The no-quenching inference is itself a null result (ratios of pT imbalance and dijet azimuthal separation show 'no significant differences'), so it cannot independently validate the event classes. If the BBC proxy misorders events, the observed trigger- and recoil-side suppression, and the symmetry between sides, could be a selection artifact rather than evidence for an EA-Q^2 anti-correlation. Because every quantitative input is imported from Ref. [19], the validation needed to support the conclusion is not present in this paper.","agreement_with_reader":"agree"},"referee_report":{"model":"deepseek-v4-flash","summary":"The manuscript is a short proceedings-style report on behalf of the STAR Collaboration, summarizing recent STAR jet measurements at sqrt(s_NN) = 200 GeV. It covers three topics: inclusive charged-particle jet R_CP and R_AA in Au+Au collisions; semi-inclusive direct-photon+jet and pi0+jet I_AA in central Au+Au collisions; and event-activity-dependent semi-inclusive jet spectra in p+Au collisions using a BBC-based event-activity classifier. The central claims are that Au+Au jet yields are significantly suppressed, consistent with strong jet interactions with the quark-gluon plasma, and that high-event-activity p+Au suppression is not due to in-medium energy loss but to an anti-correlation between event activity and the underlying hard scale Q^2. All quantitative results and figures are taken from Refs. [5], [17], and [19].","tokens_in":7488,"tokens_out":6190,"duration_ms":67993,"significance":"If the results hold, the Au+Au R_CP/R_AA and I_AA measurements provide important RHIC-era constraints on jet quenching, and the p+Au event-activity study bears directly on the question of whether small-system suppression is a final-state or selection effect. The manuscript is a useful, concise entry point to these STAR results and clearly credits the underlying references. Its main limitation, however, is that it contains no original numerical data or analysis: every figure is labelled as taken from a prior STAR publication, so the scientific value resides in the referenced papers rather than in this manuscript itself.","major_comments":[{"comment":"The conclusion that high-event-activity suppression in p+Au reflects a negative correlation between event activity and Q^2 rather than in-medium energy loss is not supported by the material presented in this manuscript. The only validation of the BBC ADC event-activity classifier is the sentence: 'Despite detector signal saturation effects, correlations between EA measured by the BBC and midrapidity charged particle density confirm the suitability of this method.' No saturation correction, correlation strength, or demonstration that the 30% low/high event-activity classes are not in a saturated plateau is given. Because the pT-imbalance and dijet azimuthal-separation ratios show no significant differences, they are null results and cannot independently validate the event classes. The authors should include the event-activity validation from Ref. [19] or explicitly cite the specific figure/table there before the Q^2 anti-correlation interpretation can be assessed.","section":"§3.3, Fig. 5, and Conclusions"},{"comment":"The text states that IAA is consistent for gamma_direct and pi0 triggers 'within the same E_trig^T bin,' but the figure and surrounding text show different bins: 11 < E_trig^T < 15 GeV for pi0+jet and 15 < E_trig^T < 20 GeV for gamma_direct+jet. Please clarify whether a common trigger-energy bin is used, or correct the text to say that the comparison is made for the highest measured bin of each trigger. As written, the trigger-comparison claim is internally inconsistent and cannot be evaluated.","section":"§3.2, Fig. 4, and text near 'within the same E_trig^T bin'"},{"comment":"The manuscript reports fully-corrected results and physical interpretations but provides no numerical values, no uncertainty tables, no correction details, and no analysis of its own; all central plots are reproduced from Refs. [5], [17], and [19]. If this is intended as a research article, it is not self-contained. If it is a proceedings summary, that scope should be stated explicitly in the abstract and introduction, and the figures should be labelled as reproduced from those references with a note that the definitive results appear there.","section":"§3 (overall), Figs. 2–5"}],"minor_comments":[{"comment":"In the full text, 'Inp+Au collisions' on page 2 is missing a space; there are also several places where mathematical symbols run into surrounding text (e.g., '√sNN' is used without a separating space before '=').","section":"Abstract and §3 intro"},{"comment":"The phrase 'which compared jet yield measured in central collisions' should read 'which compares the jet yield measured in central collisions'; the current wording is grammatically incomplete.","section":"Eq. (1)"},{"comment":"Figure 1 is labelled as taken from Ref. [1], but Ref. [1] is a Universe article on di-hadron correlations, not a STAR detector paper; the authors should cite the appropriate STAR detector publication or the original source of the 3D model.","section":"Fig. 1 and Ref. [1]"},{"comment":"The statement that 'the absence of a strong pT dependence in jet RCP contrasts with the more pronounced pT dependence observed for charged hadrons' would be clearer with an explicit statement of the pT range over which the comparison is made, since the hadron RCP data are shown only over a limited range.","section":"§3.1, Fig. 2"},{"comment":"Ref. [17] is listed as arXiv:2309.00145 without noting whether it has since been published in a journal; if it has, the published citation should be given. Also, the reference list uses inconsistent formatting for collaboration names and journal titles.","section":"Reference list"}],"recommendation":"major_revision","confidential_remarks":"To the editor: This is clearly a conference-proceedings summary rather than a full research paper. If the journal's scope is original research, the manuscript is not a fit for a research article. The scientific content relies entirely on the collaboration's published papers, and the potentially new interpretive step (the Q^2 anti-correlation in p+Au) is already presented in Ref. [19]. The authors should be asked to state the proceedings scope explicitly and to address the event-activity validation issue in Section 3.3 before publication. "},"author_rebuttal":null,"desk_editor":{"model":"deepseek-v4-flash","letter":"Two things to know about arXiv:2507.23471. First, it is a conference proceedings summary, not a new measurement: every result figure is explicitly taken from prior STAR papers [5], [17], [19]. Second, as a summary it is honest and readable: it defines RCP, RAA, IAA cleanly, flags the pitfalls of comparing RHIC/LHC RCP values, and does not overstate its case. The physics content is the STAR collaboration's published results, and this paper adds no new equation or data to them.\n\nWhat it does well: it is a compact, well-organized overview of recent STAR jet measurements, and it gets the caveats right—e.g., that similar RCP values at different collision energies do not imply identical quenching, and that charged-hadron and jet suppression cannot be compared at the same pT. The prose is clear and the figures are appropriately sourced. For a reader who wants a quick orientation to the STAR jet program at RHIC, this is a useful document.\n\nThe soft spot is the p+Au section. The conclusion that high-EA suppression is an event-activity/hard-scale anti-correlation rather than in-medium energy loss rests on the BBC ADC event-activity proxy. The paper acknowledges saturation but validates the proxy in a single sentence: 'correlations between EA measured by the BBC and midrapidity charged particle density confirm the suitability of this method.' No saturation correction, correlation strength, or test that the 30% high/low cut avoids a saturated plateau is shown. The stress-test is on target. That said, this is a proceedings summary, and the detailed analysis is in the peer-reviewed PRC paper [19]; a reader who wants to probe the proxy should go there. For the present paper, the claim is under-supported but not misleading—it faithfully reports the collaboration's interpretation.\n\nThe citations are appropriate: the paper cites the original STAR measurements and the model calculations used for RAA comparisons. No circular reasoning in the derivation sense; the self-citations are normal collaboration summaries.\n\nOverall: this is a competent proceedings contribution with no new science. A serious referee would have nothing to referee beyond the accuracy of the summary, which appears fine. I would not send it to referees for a journal; if the venue is a proceedings with editorial review, it is acceptable. Worth reading for a quick survey, but the real physics evaluation should be done on [5], [17], and [19].","headline":"A clean, honest proceedings summary of existing STAR jet results; the only soft spot is the under-supported p+Au event-activity claim, which is better assessed in the cited PRC paper.","tokens_in":8037,"tokens_out":2552,"would_cite":false,"duration_ms":28069,"reading_group":"maybe","serious_thinker":"yes","would_accept_peer_review":false},"rs_alignment":null,"lean_confirmation":null,"pith_extraction":{"msc":[],"pacs":["25.75.-q","13.87.-a"],"model":"deepseek-v4-flash","headline":"STAR jet measurements at 200 GeV show strong jet quenching in Au+Au collisions and trace the p+Au suppression to an event-activity selection bias rather than to in-medium energy loss.","keywords":["jet quenching","quark-gluon plasma","heavy-ion collisions","p+Au collisions","Au+Au collisions","event activity","semi-inclusive jets","RHIC"],"falsifier":"Redo the p+Au high-/low-EA jet-yield comparison using an event-activity estimator that does not saturate and is separated from the hard process (for example, spectator energy or a segmented forward detector): if the equal trigger-side and recoil-side suppression and the unchanged dijet $p_{\\mathrm{T}}$ imbalance survive the redefinition, the anti-correlation interpretation is supported; if the suppression becomes recoil-side dominated or disappears, the paper's p+Au conclusion fails.","tokens_in":7086,"feed_emoji":"⚛️","tokens_out":14076,"duration_ms":138605,"temperature":0.7,"pith_summary":"This paper argues that jet suppression measured at RHIC at $\\sqrt{s_{\\mathrm{NN}}}=200$ GeV has two distinct causes depending on collision system. In Au+Au, central collisions suppress charged-particle jet yields to $R_{\\mathrm{CP}} \\sim 0.5$ relative to peripheral collisions, roughly independent of jet $p_{\\mathrm{T}}$, and the data are consistent with theoretical models of parton energy loss in the quark-gluon plasma. In p+Au, high-event-activity events also suppress jet yields, but the suppression is equal on trigger and recoil sides and leaves dijet momentum balance and azimuthal separation unchanged, which is not the signature of in-medium energy loss. The paper attributes the p+Au suppression to a negative correlation between the forward event-activity measure and the underlying hard-scattering scale $Q^2$, so that high-EA event classes preferentially select softer hard scatters.","feed_headline":"Au+Au jets quench; p+Au suppression is a selection bias","feed_subtitle":"STAR's 200 GeV data tie jet suppression to the quark-gluon plasma in gold-gold and to event activity in proton-gold.","key_machinery":"The argument is carried by semi-inclusive, trigger-normalized jet yields and by forward event-activity selection. Jets are reconstructed with the anti-$k_{\\mathrm{T}}$ algorithm for radii $R=0.2$--$0.5$ from charged tracks in the TPC, with full jets adding BEMC energy; underlying-event contributions are subtracted using mixed-event techniques. The semi-inclusive observable $I_{\\mathrm{AA}}$ compares trigger-normalized recoil-jet yields in AA to pp for identical $\\gamma$ or $\\pi^0$ triggers, cancelling trigger and underlying-event biases so that remaining suppression is attributable to the medium. Inclusive jet results use $R_{\\mathrm{CP}}$ (central vs peripheral yields scaled by binary-collision counts) and $R_{\\mathrm{AA}}$ (AA vs pp yields). For p+Au, the key mechanism is the BBC in the Au-going direction ($\\eta \\in [-5,-3.4]$): its summed ADC defines high- and low-event-activity classes, and the large pseudorapidity gap between the event-activity measurement and midrapidity jets is what allows the paper to separate event-activity selection from in-medium effects.","core_discovery":"On its own terms, the paper establishes that jets are strongly modified in central Au+Au at $\\sqrt{s_{\\mathrm{NN}}}=200$ GeV and not modified in the way energy loss would produce in high-EA p+Au. The Au+Au evidence is threefold: inclusive jet $R_{\\mathrm{CP}} \\sim 0.5$ with weak $p_{\\mathrm{T}}$ dependence; $R_{\\mathrm{AA}}$ for charged jets described by several transport and effective-theory calculations; and semi-inclusive $\\gamma$- and $\\pi^0$-triggered recoil jet yields suppressed at $R=0.2$ and less so at $R=0.5$, indicating energy redistribution to larger angles. The p+Au evidence is that high-EA events suppress trigger-side and recoil-side jets equally and show no significant change in the ratio of $p_{\\mathrm{T}}$ imbalance or azimuthal dijet separation between high- and low-EA events. Because such symmetric suppression is not a quenching signature, the paper concludes the small-system suppression reflects an event-activity/hard-scale anti-correlation rather than jet-medium interaction.","pith_inferences":["The p+Au result implies that event-activity-based \"centrality\" in small systems may systematically select lower-$Q^2$ hard scatters; other small-system observables that use the same event-activity classes may carry the same bias.","A direct testable consequence is that the high-/low-EA jet-yield ratio in p+Au should be reproducible by Monte Carlo simulations without any medium, provided the simulation implements the same BBC event-activity selection.","The same forward-activity method could be applied to asymmetric small systems such as O+Au or d+Au to see whether the anti-correlation scales with the size of the heavy ion, and to future high-luminosity RHIC data for full-jet reconstruction.","If the event-activity/hard-scale anti-correlation is the cause, the suppression in p+Au should be independent of jet radius, unlike the Au+Au case where the $R$ dependence of $I_{\\mathrm{AA}}$ is a quenching signature."],"forward_implications":["Central Au+Au collisions at $\\sqrt{s_{\\mathrm{NN}}}=200$ GeV suppress inclusive charged-jet yields by roughly a factor of two, a signature of strong jet interaction with the quark-gluon plasma at RHIC energies.","The weakening of semi-inclusive recoil-jet suppression from $R=0.2$ to $R=0.5$ shows that a larger jet cone recovers more of the lost energy, constraining the angular scale of medium-induced energy redistribution.","The $\\gamma$- and $\\pi^0$-triggered recoil yields are consistent within uncertainties, implying a larger average energy loss for $\\pi^0$-triggered recoil jets given their steeper trigger spectrum, which constrains the flavor and path-length dependence of quenching.","In p+Au, high-EA and low-EA events show no significant difference in dijet $p_{\\mathrm{T}}$ imbalance or azimuthal separation, ruling out a strong in-medium energy-loss component in the observed high-EA jet suppression.","The measured inclusive jet spectra extend to about 50 to 60 GeV/c, providing an RHIC baseline for comparing jet suppression patterns with LHC data after accounting for spectral-shape and quark/gluon-fraction differences."],"supporting_citations":[{"why":"supplies the Pb+Pb charged-jet R_CP baseline at 2.76 TeV against which the RHIC suppression is compared.","marker":"[2]"},{"why":"provides the charged-hadron R_CP at RHIC used to contrast hadron and jet suppression patterns.","marker":"[3]"},{"why":"supplies the inclusive charged-particle jet spectra, R_CP and R_AA results, and the leading-constituent cut used in this analysis.","marker":"[5]"},{"why":"provides the Monte Carlo p+p reference spectrum used in the R_AA numerator.","marker":"[6]"},{"why":"gives the theoretical basis for using a tagged photon as a clean reference for recoil-jet energy loss.","marker":"[15]"},{"why":"previous gamma/pi0 triggered jet-correlation study that motivates the color-factor and path-length comparison.","marker":"[16]"},{"why":"companion measurement from which the semi-inclusive gamma/pi0+jet I_AA results are taken.","marker":"[17]"},{"why":"Glauber model supplies the binary-collision scaling used to define R_CP and R_AA.","marker":"[18]"},{"why":"establishes the BBC event-activity proxy and its anti-correlation with hard processes, the basis for the p+Au conclusion.","marker":"[19]"}],"fun_headline_variants":["Au+Au jets quench; p+Au suppression is selection bias","STAR: Jet quenching in Au+Au, not in high-EA p+Au","Au+Au jet quench real, p+Au suppression bias","STAR pins jet suppression to QGP in Au+Au only"],"cache_read_input_tokens":3200,"weakest_assumption_plain":"The load-bearing assumption is that the summed BBC signal in the Au-going direction, despite detector saturation, is a valid event-activity proxy whose correlation with the hard-scattering scale is not itself an artifact of autocorrelations with the jets measured at midrapidity.","fun_headline_variants_meta":{"raw":{"variants":["Au+Au jets quench; p+Au suppression is selection bias","STAR: Jet quenching in Au+Au, not in high-EA p+Au","Au+Au jet quench real, p+Au suppression bias","STAR pins jet suppression to QGP in Au+Au only"]},"model":"deepseek-v4-flash","effort":"low","cost_usd":0.0002,"raw_usage":{"total_tokens":1432,"prompt_tokens":1060,"completion_tokens":372,"prompt_tokens_details":{"cached_tokens":384},"prompt_cache_hit_tokens":384,"prompt_cache_miss_tokens":676,"completion_tokens_details":{"reasoning_tokens":291}},"tokens_in":676,"tokens_out":372,"duration_ms":4226,"temperature":1.0,"reasoning_tokens":291,"cache_read_input_tokens":384,"cache_creation_input_tokens":0},"cache_creation_input_tokens":0},"created_at":"2026-08-06T10:42:11.765390+00:00","model_set":{"reader":"deepseek-v4-flash"},"falsifier":"Redo the p+Au high-/low-EA jet-yield comparison using an event-activity estimator that does not saturate and is separated from the hard process (for example, spectator energy or a segmented forward detector): if the equal trigger-side and recoil-side suppression and the unchanged dijet $p_{\\mathrm{T}}$ imbalance survive the redefinition, the anti-correlation interpretation is supported; if the suppression becomes recoil-side dominated or disappears, the paper's p+Au conclusion fails.","supporting_citations":[{"cited_title":"Measurement of charged jet suppression in Pb-Pb collisions at √sNN = 2.76 TeV","cited_arxiv_id":null,"evidence_quote":"supplies the Pb+Pb charged-jet R_CP baseline at 2.76 TeV against which the RHIC suppression is compared."},{"cited_title":"Transverse-Momentum and Collision-Energy Dependence of High- pT Hadron Suppression in Au+Au Collisions at Ultrarelativistic Energies","cited_arxiv_id":null,"evidence_quote":"provides the charged-hadron R_CP at RHIC used to contrast hadron and jet suppression patterns."},{"cited_title":"-N., Huang, Z., & Sarcevic, I","cited_arxiv_id":null,"evidence_quote":"gives the theoretical basis for using a tagged photon as a clean reference for recoil-jet energy loss."},{"cited_title":"L., Reygers, K., Sanders, S","cited_arxiv_id":null,"evidence_quote":"Glauber model supplies the binary-collision scaling used to define R_CP and R_AA."}],"review_version":1}