{"id":"c7342d18-9f70-4a0d-9260-1c9fc9c9530f","arxiv_id":"2506.14989","paper_version":1,"verdict":"CONDITIONAL","confidence":"MODERATE","novelty_score":5.0,"correctness_risk":"medium","formal_verification":"none","parameter_count":1,"one_line_summary":"First ALICE measurements of charged-particle density at mid and forward rapidity at the new LHC Run 3 energies of 13.6 TeV pp and 5.36 TeV Pb-Pb.","lead":"This paper reports the first measurements of charged-particle pseudorapidity density in proton-proton collisions at 13.6 TeV and lead-lead collisions at 5.36 TeV, using upgraded ALICE detectors. It provides new reference data for tuning quantum chromodynamics models and confirms the established energy scaling of particle production.","discovery_kind":"extension","skeptic_critique":{"model":"deepseek-v4-flash","headline":"The 'first measurements' claim appears contradicted by the CMS Pb–Pb result cited in the same paper; verify priority before accepting the central claim as stated.","rationale":"The reader's weakest_assumption focused on Pythia8/Angantyr acceptance and efficiency corrections. That is a legitimate concern for any ALICE dN/dη measurement, but it is not the most load-bearing issue here: the same correction framework is standard in ALICE analyses and the proceedings gives too little detail to either confirm or refute a bias. The more direct and checkable threat to the central claim is the 'first measurements' wording. The paper itself cites and displays a CMS result at 5.36 TeV in the same observable, so the abstract's claim of being first is at least questionable and likely false for the Pb–Pb leg. Because the physics content may still be valuable and correct, the appropriate outcome is to keep the reader's CONDITIONAL verdict, with the added condition that the novelty claim must be verified against the cited CMS publication and reworded if necessary. This does not change the overall verdict category, hence UNCHANGED, but it identifies a different, more decisive weakness than the one named by the reader.","tokens_in":3877,"tokens_out":9037,"duration_ms":85570,"concrete_test":"Retrieve CMS PLB 861 (2025) 139279 and check whether it reports dN_ch/dη for Pb–Pb at sqrt(s_NN)=5.36 TeV in overlapping centrality and pseudorapidity ranges, and confirm its publication date relative to the ALICE preprint submission (17 Jun 2025). If the CMS paper indeed reports the same observable at the same energy before the ALICE preprint, then the abstract's 'first measurements' phrase must be qualified to 'first ALICE measurements' or otherwise restricted. If the CMS paper does not report dN_ch/dη, this concern is dismissed.","verdict_should_be":"UNCHANGED","load_bearing_attack":"The central claim as written in the abstract is that these are 'the first measurements' of dN_ch/dη at both 13.6 TeV pp and 5.36 TeV Pb–Pb. This rests on the factual premise that no prior published measurement exists at these energies. The manuscript itself undermines that premise for the Pb–Pb leg: Section 4.2 and Figure 2 compare the new ALICE points with 'CMS PLB 861 (2025) 139279' at sqrt(s_NN)=5.36 TeV, calling them 'recent results from the CMS experiment.' If that CMS paper reports the charged-particle pseudorapidity density in Pb–Pb at 5.36 TeV—which the comparison in Figure 2 strongly implies—then the ALICE measurement is not the first such measurement, only the first by ALICE. The numerical results may be sound, but the central novelty claim as worded in the abstract is not supported. This is more directly load-bearing than the standard Pythia8/Angantyr efficiency-correction concern because it affects whether the central claim is true as stated, independent of detector modelling.","agreement_with_reader":"disagree"},"referee_report":{"model":"deepseek-v4-flash","summary":"This proceedings paper reports ALICE measurements of the charged-particle pseudorapidity density, dN_ch/dη, in pp collisions at √s = 13.6 TeV (midrapidity |η|<0.5 and forward rapidity −3.6<η<−2.4 using the new MFT) and in Pb–Pb collisions at √s_NN = 5.36 TeV for centrality classes 0–5% to 70–80%. The results are compared with Pythia8 tunes and EPOS4, with a CMS Pb–Pb measurement at the same energy, and with ALICE data at lower energies scaled by a power law. The paper is a conference proceeding: it describes the event selection, track types, and Monte-Carlo-based corrections, but contains no numeric tables, no detailed systematic breakdown, and no public data release.","tokens_in":4075,"tokens_out":6599,"duration_ms":56890,"significance":"If the numerical results are correct, the pp forward-rapidity dN/dη measurement with the MFT is a genuinely new ALICE result, and the Pb–Pb data provide a useful cross-check of particle production at a new LHC energy. The large event samples (3.0/2.1/1.1 billion events for the three analyses) and the comparisons with the CMS result and with energy-scaled ALICE data give the paper value as a preliminary reference. However, the central novelty claim as written is not supported for the Pb–Pb leg, and the scaling comparison contains a numerical inconsistency. These issues are correctable, and the underlying measurement appears plausible, but the current version needs revision before the claims can be accepted.","major_comments":[{"comment":"The abstract claims 'first measurements' of dN_ch/dη in pp at 13.6 TeV and in Pb–Pb at 5.36 TeV. Section 4.2 and Figure 2 compare the new ALICE Pb–Pb results with CMS (PLB 861 (2025) 139279) at the same √s_NN = 5.36 TeV. That CMS paper reports charged-particle pseudorapidity densities in Pb–Pb at this energy, as the comparison in Figure 2 confirms. The claim should be restricted to 'first ALICE measurements' or otherwise qualified (e.g., 'first combined midrapidity and forward-rapidity measurements'); as written, the central novelty claim is contradicted by the manuscript's own cited reference.","section":"Abstract and Section 4.2"},{"comment":"The text states that the scaling factors 1.27 (for 2.76 TeV) and 1.06 (for 5.02 TeV) 'correspond to the observed √s_NN^0.156 dependence of multiplicity in central collisions'. Direct calculation gives (5.36/2.76)^0.156 = 1.109 and (5.36/5.02)^0.156 = 1.010. The stated factors are therefore inconsistent with the quoted exponent. Please clarify how the 1.27 and 1.06 factors are derived, or correct the exponent; the claim of good agreement after scaling depends on this.","section":"Section 4.2"},{"comment":"The corrections for acceptance and tracking efficiency are applied using Pythia8/Angantyr simulations, but no systematic uncertainty associated with this correction is given, and no validation (closure tests, comparison of simulated and measured track distributions) is presented. The reported dN/dη values and the comparison with models in Figures 1–2 depend directly on these corrections, so the systematic budget is incomplete as presented.","section":"Section 3"},{"comment":"No numeric results are tabulated: neither the dN_ch/dη values nor the centrality-dependent values in Figure 2 are given with their statistical and systematic uncertainties; the figures only show bands. As a measurement paper, this prevents the reader from using the results or checking the quoted uncertainties. A table of values or a public data release should be added, or at least the results should be made available as supplemental material.","section":"General"}],"minor_comments":[{"comment":"The phrase '0-5%)' contains an unmatched parenthesis; it should read '0–5%'.","section":"Abstract and Introduction"},{"comment":"The forward-rapidity range is written as '−3.6<|η|<−2.4', which is mathematically impossible because |η| is non-negative. It should be '−3.6<η<−2.4' or '2.4<|η|<3.6'.","section":"Abstract, Sections 1 and 4.1"},{"comment":"The sentence 'The ALICE experiment is able to measure charged-particle multiplicity density with tracks in the central and forward rapidity region for the first time' is ambiguous; specify whether this refers to the first simultaneous measurement in both regions with ALICE.","section":"Section 4.1"},{"comment":"The version of Pythia8/Angantyr used is not specified; please add the version number.","section":"Section 3"},{"comment":"The phrase 'assuming full uncorrelation between data sets' should be rephrased, e.g., 'assuming fully uncorrelated systematic uncertainties between data sets.'","section":"Section 4.2"}],"recommendation":"major_revision","confidential_remarks":"This is a short proceedings contribution. The two main technical issues—the unsupported 'first measurements' claim and the scaling-factor inconsistency—are both correctable. The Pythia8/Angantyr correction uncertainty also needs to be stated, even if a full systematic breakdown is deferred to a later publication. If the authors correct these points, the paper would be acceptable as a proceedings article reporting preliminary reference measurements."},"author_rebuttal":null,"desk_editor":{"model":"deepseek-v4-flash","letter":"Quick read of the ALICE proceedings. What is actually new: dN_ch/dη values in pp at 13.6 TeV (mid- and forward-rapidity via MFT) and Pb–Pb at 5.36 TeV across centralities. Those are real data points, not in the earlier ALICE papers. The forward-rapidity pp measurement is a first for ALICE, and the midrapidity pp point extends the energy series. The analysis follows the standard ALICE recipe: INEL>0 selection, global plus ITS-only tracks, Pythia8/Angantyr corrections, Glauber centrality from FT0. That is sound and the cross-checks against scaled 2.76 and 5.02 TeV data and against CMS look consistent. Credit where due: the paper is compact, the figures are informative, and the model comparisons (Pythia8 tunes, EPOS4) give the reader something to think about rather than just numbers.\n\nThe soft spot that matters is the abstract. It says these are the first measurements of dN_ch/dη in Pb–Pb at 5.36 TeV. Then Section 4.2 and Figure 2 compare with CMS PLB 861 (2025) 139279 at the same energy, calling them 'recent results from the CMS experiment.' If CMS reported the same observable at that energy—which the comparison strongly implies—then the ALICE result is not first; it is first by ALICE, or first with these acceptance cuts. The stress-test note lands on this. It is the central claim of the abstract, and it is wrong as written. The fix is easy: say 'first ALICE measurements' or 'first ALICE results at these energies' and let the data speak. As is, a referee would rightly bounce it.\n\nOther soft spots are more minor. There are no numerical tables of the dN/dη values or the systematic breakdown; that is normal for a proceedings, but it means the reader cannot independently check the quoted uncertainties. The rate of typos is a bit high ('0-5$\\%)', 'T eV', 'Pb-–Pb'), which is cosmetic. The use of the 0.156 scaling exponent from the prior ALICE paper is fine—it is used only to place old data on the same energy scale for comparison, and it does not constrain the new measurement. The Pythia8/Angantyr efficiency correction is the usual load-bearing assumption; the backup is that the same method matched CMS at 5.36 TeV, which is reassuring.\n\nWho benefits from this paper: people building or constraining QCD Monte Carlo generators, and the heavy-ion soft-QCD community. It is a conference proceedings, so it will not be a landmark, but it contains the first numbers at these energies from ALICE and deserves to be citable. I would send it to peer review at whatever venue collects these proceedings, provided the first-measurements claim is corrected. With that correction, it is a legitimate, incremental but useful contribution.","headline":"New ALICE dN/dη points at Run 3 energies are genuine and useful, but the abstract's 'first measurements' claim collides with the CMS paper cited in the same proceedings; easy to fix, but it should be fixed.","tokens_in":4613,"tokens_out":1113,"would_cite":true,"duration_ms":12339,"reading_group":"yes","serious_thinker":"yes","would_accept_peer_review":true},"rs_alignment":null,"lean_confirmation":null,"pith_extraction":{"msc":[],"pacs":[],"model":"deepseek-v4-flash","headline":"This paper reports the first measurements of the charged-particle pseudorapidity density in pp collisions at 13.6 TeV and in Pb-Pb collisions at 5.36 TeV, from ALICE Run 3 data.","keywords":["charged-particle pseudorapidity density","dN/deta","pp collisions at 13.6 TeV","Pb-Pb collisions at 5.36 TeV","ALICE Run 3","forward rapidity","centrality classes","Pythia8/Angantyr"],"falsifier":"If the same raw events were corrected with an independent efficiency estimate—for example from embedding simulated tracks into real collisions or from a tag-and-probe comparison using the overlapping ITS, TPC, and MFT detectors—and the resulting ${\\rm d}N_{\\rm ch}/{\\rm d}\\eta$ differed from the quoted values by more than the reported systematic uncertainties, the correction premise would be falsified.","tokens_in":3672,"feed_emoji":"⚛️","tokens_out":9605,"duration_ms":75052,"temperature":0.7,"pith_summary":"Protons colliding at $\\sqrt{s}=13.6$ TeV and lead nuclei at $\\sqrt{s_{\\rm NN}}=5.36$ TeV are among the highest collision energies reached at a particle collider. This paper reports the first measurements of the charged-particle pseudorapidity density ${\\rm d}N_{\\rm ch}/{\\rm d}\\eta$—the number of charged particles produced per unit of pseudorapidity, which measures how far a particle's direction is from the beam axis—in proton-proton collisions at 13.6 TeV and in lead-lead collisions at 5.36 TeV. The values come from upgraded ALICE detector data recorded in LHC Run 3 and set new reference points for how particle production grows with collision energy. They are compared with model predictions and with earlier measurements scaled to the new energies, checking whether the established energy-scaling trend continues.","feed_headline":"First particle-density measurements at 13.6 TeV pp and 5.36 TeV Pb-Pb","feed_subtitle":"Run 3 data from ALICE set new reference points for particle production and test model predictions.","key_machinery":"The measurement is carried by the upgraded ALICE apparatus: the Inner Tracking System and GEM-based Time Projection Chamber provide midrapidity global tracks, and the newly installed Muon Forward Tracker supplies forward-rapidity tracks in the range $-3.6<\\eta<-2.4$. The Fast Interaction Trigger selects the events and, in Pb-Pb, its amplitude is fitted with a Glauber Monte Carlo model to assign centrality classes. Corrections for detector acceptance and tracking efficiency are applied using Pythia8/Angantyr simulations. The central object is the charged-particle pseudorapidity density, ${\\rm d}N_{\\rm ch}/{\\rm d}\\eta$, obtained by counting primary charged particles in defined $\\eta$ intervals; the energy-scaling comparison uses the observed $(\\sqrt{s_{\\rm NN}})^{0.156}$ growth of central multiplicity.","core_discovery":"The paper reports the first measurements of ${\\rm d}N_{\\rm ch}/{\\rm d}\\eta$ at $\\sqrt{s}=13.6$ TeV pp and $\\sqrt{s_{\\rm NN}}=5.36$ TeV Pb-Pb collisions using ALICE Run 3 data. In pp collisions, the midrapidity ($|\\eta|<0.5$) result and the forward-rapidity ($-3.6<\\eta<-2.4$) result from the new Muon Forward Tracker agree with Pythia8 Monash and with a QCD-based color-reconnection tune; a gluon-move tune overpredicts midrapidity by about 4%, and EPOS 4 underpredicts midrapidity by about 5% and overpredicts forward rapidity by about 15%. In Pb-Pb collisions, the charged-particle density normalized by the mean number of participant nucleons decreases by a factor of about 1.8 from central (0-5%) to peripheral (70-80%) events. Scaled measurements from 2.76 and 5.02 TeV agree with the new 5.36 TeV points, and the ALICE and CMS results agree within uncertainties despite different centrality and pseudorapidity definitions.","pith_inferences":["A possible extension is to measure dN/deta in pp collisions as a function of event multiplicity, which would show whether the forward-to-midrapidity ratio rises, falls, or stays flat with activity; the current data only cover the inclusive INEL>0 class.","If the forward-rapidity overprediction by EPOS 4 persists after the final published analysis, the MFT's forward coverage would become a sharper testing ground for hydrodynamical versus non-hydrodynamical treatment of the event periphery.","The scaling comparison uses fully uncorrelated uncertainties between data sets; a joint analysis treating the common systematic sources would let the quoted 0.156 exponent be tested more stringently at 5.36 TeV."],"forward_implications":["The 13.6 TeV pp measurement gives model builders a new reference point for tuning soft quantum-chromodynamics processes at the highest proton-proton energy at the LHC.","The forward-rapidity points from the Muon Forward Tracker narrow the allowed pseudorapidity-shape predictions, since EPOS 4 overshoots those points by about 15%.","The Pb-Pb result shows that the per-participant charged-particle density falls by roughly a factor 1.8 from central to peripheral collisions at 5.36 TeV, extending the known centrality trend to a new energy.","Multiplying the 2.76 and 5.02 TeV measurements by factors of 1.27 and 1.06 brings them into agreement with the 5.36 TeV data, supporting the same power-law energy growth in central collisions.","Agreement between ALICE and CMS at 5.36 TeV indicates the new reference point is robust against different centrality estimators and different pseudorapidity acceptances."],"supporting_citations":[{"why":"Describes the upgraded ITS2, TPC, FIT, and MFT detectors that recorded the Run 3 data.","marker":"[2]"},{"why":"Supplies the Glauber Monte Carlo model used to fit the FT0 amplitude and define Pb-Pb centrality classes.","marker":"[3]"},{"why":"Pythia8/Angantyr simulations used to correct the raw track counts for acceptance and tracking efficiency.","marker":"[6]"},{"why":"Provides the measured (sqrt(s_NN))^0.156 energy-scaling dependence used to shift the earlier Pb-Pb data for comparison.","marker":"[1]"},{"why":"CMS measurement in Pb-Pb at 5.36 TeV used as the cross-experiment consistency check.","marker":"[7]"},{"why":"Earlier ALICE Pb-Pb dN/deta measurement at 2.76 TeV, scaled by 1.27, for comparison with the new data.","marker":"[8]"},{"why":"Earlier ALICE Pb-Pb dN/deta measurement at 5.02 TeV, scaled by 1.06, for comparison with the new data.","marker":"[10]"}],"fun_headline_variants":["First particle-density data at 13.6 TeV pp and 5.36 TeV Pb-Pb","ALICE debuts particle-density results at two new LHC energies","ALICE reports first charged-particle densities at 13.6 TeV pp and 5.36 TeV Pb-Pb","First particle-density data from ALICE at 13.6 TeV pp and 5.36 TeV Pb-Pb","New particle-density benchmarks at 13.6 TeV pp and 5.36 TeV Pb-Pb"],"cache_read_input_tokens":3200,"weakest_assumption_plain":"The measurement stands on the assumption that the Pythia8/Angantyr simulation reproduces the detector's acceptance and tracking efficiency well enough that the corrections applied to the raw track counts do not bias the reported ${\\rm d}N_{\\rm ch}/{\\rm d}\\eta$ values.","fun_headline_variants_meta":{"raw":{"variants":["First particle-density data at 13.6 TeV pp and 5.36 TeV Pb-Pb","ALICE debuts particle-density results at two new LHC energies","ALICE reports first charged-particle densities at 13.6 TeV pp and 5.36 TeV Pb-Pb","First particle-density data from ALICE at 13.6 TeV pp and 5.36 TeV Pb-Pb","New particle-density benchmarks at 13.6 TeV pp and 5.36 TeV Pb-Pb"]},"model":"deepseek-v4-flash","effort":"low","cost_usd":0.00096,"raw_usage":{"total_tokens":4141,"prompt_tokens":1052,"completion_tokens":3089,"prompt_tokens_details":{"cached_tokens":384},"prompt_cache_hit_tokens":384,"prompt_cache_miss_tokens":668,"completion_tokens_details":{"reasoning_tokens":2956}},"tokens_in":668,"tokens_out":3089,"duration_ms":20729,"temperature":1.0,"reasoning_tokens":2956,"cache_read_input_tokens":384,"cache_creation_input_tokens":0},"cache_creation_input_tokens":0},"created_at":"2026-08-07T00:09:09.720234+00:00","model_set":{"reader":"deepseek-v4-flash"},"falsifier":"If the same raw events were corrected with an independent efficiency estimate—for example from embedding simulated tracks into real collisions or from a tag-and-probe comparison using the overlapping ITS, TPC, and MFT detectors—and the resulting ${\\rm d}N_{\\rm ch}/{\\rm d}\\eta$ differed from the quoted values by more than the reported systematic uncertainties, the correction premise would be falsified.","supporting_citations":[{"cited_title":"Acharya et al","cited_arxiv_id":null,"evidence_quote":"Describes the upgraded ITS2, TPC, FIT, and MFT detectors that recorded the Run 3 data."},{"cited_title":"Loizides, J","cited_arxiv_id":null,"evidence_quote":"Supplies the Glauber Monte Carlo model used to fit the FT0 amplitude and define Pb-Pb centrality classes."},{"cited_title":"Bierlich, S","cited_arxiv_id":null,"evidence_quote":"Pythia8/Angantyr simulations used to correct the raw track counts for acceptance and tracking efficiency."},{"cited_title":"Hayrapetyan et al","cited_arxiv_id":null,"evidence_quote":"CMS measurement in Pb-Pb at 5.36 TeV used as the cross-experiment consistency check."},{"cited_title":"Aamodt et al","cited_arxiv_id":null,"evidence_quote":"Earlier ALICE Pb-Pb dN/deta measurement at 2.76 TeV, scaled by 1.27, for comparison with the new data."},{"cited_title":"Adam et al","cited_arxiv_id":null,"evidence_quote":"Earlier ALICE Pb-Pb dN/deta measurement at 5.02 TeV, scaled by 1.06, for comparison with the new data."}],"review_version":1}