{"id":"c9a54696-8808-4291-92bf-8b431f85d059","arxiv_id":"2411.15756","paper_version":2,"verdict":"CONDITIONAL","confidence":"MODERATE","novelty_score":4.0,"correctness_risk":"medium","formal_verification":"none","parameter_count":7,"one_line_summary":"The Momentum-Kick Model can fit the near-side ridge in high-multiplicity pp collisions at 13 and 7 TeV, with multiplicity-dependent parameters and a speculative 14 TeV prediction.","lead":"This paper tests whether a simple momentum kick picture, where fast jet particles push surrounding partons, can explain the near-side ridge in proton-proton collisions at the LHC. The authors fit the model to 13 and 7 TeV data, add a multiplicity dependence, and give predictions for 14 TeV.","discovery_kind":"extension","skeptic_critique":{"model":"deepseek-v4-flash","headline":"All results beyond the 13 TeV ALICE/CMS fits (7 TeV, multiplicity dependence, 14 TeV prediction) rest on scaling laws Eqs. (7)-(10) inferred from a single energy pair; without an independent check, 'effectively explains' overstates the evidence.","rationale":"I read the paper as a phenomenological application of an established kinematic model. The core 13 TeV exercise, fitting three parameters to ALICE/CMS Delta-phi correlations, is a legitimate exploratory claim, though it lacks chi-square values. My stress-test focused on what would have to be true for the broader conclusion ('effectively explains' 7 TeV, multiplicity trends, and 14 TeV) to hold: the scaling relations in Eqs. (7), (9), and (10). Those relations are inferred from a single pair of energies and are not independently validated; the paper itself calls for further research on q and T systematics. The 7 TeV 'test' is weaker than it appears because q and fR<Nk> are free there, and the inverse-q relation is checked only after fitting. The multiplicity section further reduces the fit freedom to one amplitude per bin, so the shapes in Fig. 8 are not a stringent test of the scalings. The 14 TeV prediction depends on the same scalings plus an undefended +/-10% band. I also note the ATLAS under-prediction at the peak and the Table 4/conclusions numerical mismatch, both of which support the reader's caution without changing the overall verdict. Since the reader already returned CONDITIONAL with moderate confidence, my concern reinforces that judgment rather than moving it.","tokens_in":16225,"tokens_out":8580,"duration_ms":79684,"concrete_test":"Perform unconstrained three-parameter fits (or profile-likelihood scans) of T, q, and fR<Nk> to (i) the CMS 7 TeV high-multiplicity data and (ii) the ATLAS 50<=Nrec<60 bin. Compare the best-fit T with Eq. (7) (1.17 GeV) and the best-fit q with Eq. (9) (2.237 GeV). If either deviates by more than the +/-10% band used for the 14 TeV prediction, the scalings are not supported and the 7 TeV, multiplicity-dependent, and 14 TeV claims should be presented as ad hoc parametrizations rather than explanations. As a secondary check, re-derive the Table 4 A values for the lowest and highest bins to resolve the discrepancy with the conclusions.","verdict_should_be":"UNCHANGED","load_bearing_attack":"The abstract and conclusions claim the MKM 'effectively explains' the pp ridge across energies, multiplicities, and experimental conditions. The 13 TeV ALICE/CMS fits are the only place where T, q, and fR<Nk> are all free and fitted to the data; everything beyond that is carried by scaling relations. Eq. (8) is the entire empirical basis for the inverse q-multiplicity relation: one product q13/q7 x <N13>/<N7> ~ 0.93, with no uncertainty estimate. A single near-unity product cannot establish a functional dependence that is then used in Eqs. (9) and (10) to set q and T for every ATLAS multiplicity bin. Moreover, the 7 TeV comparison is not an out-of-sample test: only T is fixed by Eq. (7), while q and fR<Nk> are fitted to the 7 TeV data, so Eq. (8) is a post-hoc consistency check rather than a validation. In the multiplicity extension, q and T are imposed by the scalings and only the amplitude A is free per bin; with one free parameter per bin, reasonable visual agreement in Fig. 8 is weak evidence for the model. The 14 TeV prediction then extends the same unvalidated scalings and adds +/-10% bands without derivation. The ATLAS comparison is also overstated: Fig. 6 visibly underestimates the peak, with the authors invoking unavailable uncertainties. Finally, the conclusions quote A=0.221 and 0.111 for the lowest and highest multiplicity bins, inconsistent with Table 4 (A=0.082 and 5.949). The 13 TeV fits may stand, but the broad claims outrun the tested evidence.","agreement_with_reader":"agree"},"referee_report":{"model":"deepseek-v4-flash","summary":"The manuscript applies the Momentum-Kick Model (MKM) to the near-side ridge in high-multiplicity proton-proton collisions at 13 TeV (ALICE, CMS, ATLAS data) and 7 TeV (CMS data). The model parameters T, q, and f_R⟨N_k⟩ are fitted to the 13 TeV ALICE and CMS Δφ correlations; the same parameters are then applied to ATLAS conditions, extended to 7 TeV using a ⟨p_T⟩-ratio scaling for T and a fit for q and f_R⟨N_k⟩, and further extended to several ATLAS multiplicity bins using scaling assumptions encoded in Eqs. (9)-(11). The paper also gives a 14 TeV prediction based on extrapolating the 7-to-13 TeV energy dependence. The central conclusion is that MKM effectively explains the near-side ridge in pp collisions across these energies, multiplicities, and experimental conditions.","tokens_in":98,"tokens_out":4456,"duration_ms":92886,"significance":"If the claims are supported, the paper offers a purely kinematic alternative to hydrodynamic and glasma explanations of the ridge in small systems, with a simple few-parameter model and a falsifiable 14 TeV prediction. Credit is due for the transparent presentation of the model, the effort to restore the ATLAS data to a common ZYAM convention, and the explicit parameter tables. However, the significance is currently limited by the fact that the broad conclusions rest on scaling relations inferred from a single energy pair and on fits with one free amplitude per multiplicity bin; the directly fitted 13 TeV ALICE/CMS results are the only clearly out-of-sample-free part of the analysis.","major_comments":[{"comment":"The inverse proportionality between q and multiplicity — the load-bearing input for Eqs. (9) and (10) and for the 14 TeV extrapolation in Section 4 — rests on a single product q_13/q_7 × ⟨N_13⟩/⟨N_7⟩ ≈ 0.93 with no quoted uncertainty. Moreover, the 7 TeV comparison is not an out-of-sample test: T is fixed by Eq. (7), but q and f_R⟨N_k⟩ are fitted to the CMS 7 TeV data, so Eq. (8) is a post-hoc consistency check rather than a validation. The manuscript should either supply independent evidence for the scaling or explicitly restrict the claims to the directly fitted 13 TeV cases.","section":"§3.2, Eq. (8)"},{"comment":"The text states that the MKM result “may adequately describe” the ATLAS data within experimental uncertainties, but Fig. 6 visibly underestimates the near-side peak and no uncertainty information is shown or quoted. Invoking unavailable uncertainties makes the agreement untestable; the claim that the MKM applies to ATLAS conditions should be quantified (e.g., by a chi-square or by showing the data uncertainties) or explicitly softened.","section":"§3.2, Fig. 6"},{"comment":"The Conclusions quote A = 0.221 for the lowest multiplicity bin (50 ≤ N_rec_ch < 60) and A = 0.111 for the highest bin (130 ≤ N_rec_ch), whereas Table 4 lists A = 0.082 and A = 5.949 for the same bins. These numbers must be reconciled; as written, the concluding values contradict the table and undermine confidence in the reported fits.","section":"§3.3, Table 4 vs. Conclusions"},{"comment":"In the multiplicity extension, q and T are imposed by Eqs. (9)-(10) and only the amplitude A is free per bin, so the visual agreement in Fig. 8 is weak evidence for the model; the fit does not test the predicted multiplicity dependence of the shape. The additional trend in A (Table 4) is itself nonlinear and indicates that the assumed linear dependence in Eq. (11) is not capturing the multiplicity dependence, so the statement that MKM “effectively explains” the multiplicity dependence is stronger than the evidence shown.","section":"§3.3, Eq. (11), Fig. 8"}],"minor_comments":[{"comment":"The notation “ZY AM” is used with an unusual space; it should be “ZYAM” consistently.","section":"Throughout"},{"comment":"The expression for the beam rapidity, y_b = cosh^{-1} √s_NN / 2m_N, is ambiguous; parentheses should be added.","section":"Eq. (5)"},{"comment":"References [11] (Allison et al.) and [46] (Sisodiya et al.) appear unrelated to ridge measurements and are cited in the introductory list of ridge observations; please verify the intended sources.","section":"References [11] and [46]"},{"comment":"There are small grammatical issues (“This results are shown”) and a mismatch between the Fig. 5 caption (“Grey circles and red squares”) and the text (“Red squares and grey squares”); these should be harmonized.","section":"Section 2 and Fig. 5"}],"recommendation":"major_revision","confidential_remarks":"The paper is within the scope of a phenomenological hep-ph journal, and the directly fitted 13 TeV ALICE/CMS results are a reasonable contribution. The broad conclusions, however, outrun the validated evidence: the scaling relations are inferred from a single energy pair, the ATLAS comparison is not quantitatively supported, and the conclusions contain numerical inconsistencies with Table 4. The authors should either add validation, narrow the claims, or both. I would also ask the editor to ensure the reference list is checked, since at least two entries appear irrelevant."},"author_rebuttal":null,"desk_editor":{"model":"deepseek-v4-flash","letter":"First thing to know: this paper is not a new model; it is an application of Wong's MKM. The genuinely new pieces are the 7 TeV CMS fits, the multiplicity-dependent scalings in Eqs. (9)-(11), and the 14 TeV prediction. That is enough to make it worth a referee's time, but the headline claim that the MKM 'effectively explains' the pp ridge across energies and multiplicity bins is not supported by the evidence as presented.\n\nThe 13 TeV fits to ALICE and CMS look reasonable. Treating T as a free parameter rather than fixing it from AuAu is sensible for pp, and the finding that f_R<N_k> loses its p_T dependence is an interesting observation. The 14 TeV prediction is genuinely out-of-sample, and the paper is honest that no multiplicity/pT data exist at that energy to pin down the parameters.\n\nThe soft spots are real and roughly in the order the reader's report lists them. The entire quantitative extension beyond 13 TeV rests on Eq. (8), one product of ratios (0.93) with no uncertainty. That single near-unity product is then used to set q for every multiplicity bin and energy. The 7 TeV comparison is not out-of-sample: only T is fixed by Eq. (7); q and f_R<N_k> are fitted to the data, so Eq. (8) is a consistency check, not a prediction. In the multiplicity extension, q and T are imposed by the scalings, and only the amplitude A is free per bin; with one free parameter per bin, the visual agreement in Fig. 8 is weak evidence. The ATLAS peak in Fig. 6 is visibly underpredicted, and the comment about 'unavailable experimental uncertainties' is a hand-wave; the conclusion then claims success.\n\nThere is also a concrete internal inconsistency that any referee will catch: the conclusions quote A=0.221 and 0.111 for the lowest and highest multiplicity bins, but Table 4 gives A=0.082 and 5.949. The latter numbers are consistent with the trend; the former look like a copy-paste error or a different fit. This needs to be fixed.\n\nThe citation pattern is fine; the self-citations are to the group's earlier work and to Wong, appropriate given the model's origin. The paper does not engage deeply with hydrodynamical or CGC alternatives, but for a phenomenological kinematic description that is acceptable at this stage.\n\nWho is this for? People working on the small-system collectivity debate who want a concrete kinematic alternative to compare with. It deserves a serious referee, but the referee should ask for the internal inconsistency to be fixed, the scaling relations to be tested against an independent energy or multiplicity point, and the conclusions to be toned down from 'effectively explains' to 'provides a reasonable kinematic description.'","headline":"A legitimate extension of the Momentum-Kick Model to 7 TeV, multiplicity ranges, and 14 TeV, but the scaling relations carry too much weight and the conclusions overstate the fits.","tokens_in":17169,"tokens_out":2490,"would_cite":false,"duration_ms":20586,"reading_group":"maybe","serious_thinker":"yes","would_accept_peer_review":true},"rs_alignment":null,"lean_confirmation":null,"pith_extraction":{"msc":[],"pacs":["25.75.Gz","25.75.Ld","25.75.Nq"],"model":"deepseek-v4-flash","headline":"The Momentum-Kick Model's three parameters reproduce the near-side ridge in pp collisions at 13 and 7 TeV.","keywords":["Momentum-Kick Model","near-side ridge","high-multiplicity pp collisions","two-particle correlations","long-range correlations","kinematic model","LHC"],"falsifier":"Compare the MKM's published 14 TeV prediction, with its ±10% parameter band (q≈1.075, T≈1.193, f_R⟨N_k⟩≈2.310), to the measured long-range near-side Δφ correlation in high-multiplicity pp collisions from LHC Run 3; a data point falling outside that band, or a peak position and width that deviate from the predicted shape, would falsify the energy scaling used to extend the model.","tokens_in":16024,"feed_emoji":"⚛️","tokens_out":7636,"duration_ms":60865,"temperature":0.7,"pith_summary":"This paper claims that the near-side ridge seen in two-particle correlations from high-multiplicity proton-proton collisions can be explained by a purely kinematic mechanism: jet fragments kick nearby medium partons and drag them along the jet direction, producing a long-range excess near Δφ≈0. The authors apply the Momentum-Kick Model with three fitted parameters—the average momentum kick q, a medium temperature T, and a survival–multiplicity factor f_R⟨N_k⟩—to data from ALICE, CMS, and ATLAS at 13 TeV and from CMS at 7 TeV, and report that the model describes the measured Δφ correlations across different transverse-momentum and multiplicity ranges. They also introduce a multiplicity dependence for q, T, and f_R⟨N_k⟩ and use it to offer a testable prediction for 14 TeV collisions. If correct, the result provides a kinematic alternative to hydrodynamic or glasma explanations for small-system ridge signals, with no assumption of a quark–gluon plasma.","feed_headline":"A kick-only model reproduces the near-side ridge in pp collisions","feed_subtitle":"With just three parameters, it matches 13 and 7 TeV data and predicts what 14 TeV should show.","key_machinery":"The central object is the Momentum-Kick Model's ridge component, a phase-space transformation that shifts the initial soft-scattering parton distribution by a momentum kick q along the jet direction. The distribution is controlled by three effective parameters: q (the average transverse momentum transferred per kick), T (a medium temperature entering a modified Boltzmann-like factor), and f_R⟨N_k⟩ (the product of a survival factor and the mean number of kicked partons, acting as an overall amplitude). The model converts the initial parton transverse momentum p_Ti to p_T via p_Ti² = p_T² − 2 p_T q cos(Δφ) + q², which is what redistributes partons toward small Δφ and generates a ridge that extends over a wide Δη range. The paper's quantitative claim rests on fitting these three parameters to the experimental correlations and on two scaling rules—T proportional to ⟨p_T⟩ and q inversely proportional to multiplicity—used to carry the model to other energies and multiplicity classes.","core_discovery":"On the paper's own terms, the central discovery is that the Momentum-Kick Model—originally built for heavy-ion collisions—reproduces the long-range near-side ridge structure in high-multiplicity pp collisions at LHC energies, using a single set of physics parameters for each collision energy rather than an ad hoc per-bin adjustment. At 13 TeV the authors treat the medium temperature T as a free parameter, obtaining T=1.19 GeV, q=1.12 GeV, and f_R⟨N_k⟩=2.13 from the ALICE and CMS data, and find the same values describe the ATLAS data over a wider 0.5–5 GeV transverse-momentum window. At 7 TeV they fix T by the mean-p_T ratio, obtaining q=1.39 GeV and f_R⟨N_k⟩=1.05, and note the product (q13/q7)×(⟨N13⟩/⟨N7⟩)≈0.93, which supports an inverse proportionality between the kick q and event multiplicity. Extending this idea to ATLAS multiplicity bins yields a description of the Δφ correlations for 50≤N_rec^ch≤150, and the same energy scaling leads to the 14 TeV prediction with ±10% parameter bands.","pith_inferences":["A sharper test of the q–multiplicity scaling would be to fit the MKM to pp or p–Pb data at an intermediate energy such as 5.02 TeV: if the product (q ratio)×(multiplicity ratio) deviates from unity beyond the 13/7 TeV point's uncertainty, the inverse-proportionality rule is only a two-point coincidence.","The model's plateau assumption for the initial parton rapidity distribution could be checked by comparing its Δη dependence with the measured ridge shape at very large |Δη| (e.g., |Δη|>4), where the ATLAS window extends farther than ALICE's.","Because f_R⟨N_k⟩ is essentially a free amplitude at each multiplicity bin, the model's predictive content at 14 TeV is concentrated in the shape and peak position of the Δφ correlation rather than its absolute normalization; a shape mismatch would be a more informative failure than an overall yield offset."],"forward_implications":["If the MKM describes the ridge, the near-side ridge in small systems can be produced without collective flow or a quark–gluon plasma, so the ridge alone is not evidence for QGP in pp collisions.","The same parameter values fit ALICE and CMS at 13 TeV and are then applied to ATLAS conditions, implying the model is largely insensitive to the experimental Δη window and pT binning within the tested ranges.","The inverse relation between q and multiplicity means that as events become more crowded, each kick carries less momentum per collision, a specific kinematic prediction that can be checked at other multiplicities and energies.","The 14 TeV prediction gives a concrete, quantitative target for LHC Run 3: the height and width of the near-side ridge should fall within the ±10% parameter band shown in Figure 9.","The disappearance of pT dependence in f_R⟨N_k⟩ at 13 TeV suggests that the earlier pT-dependent normalization was an artifact of fixing T from AuAu rather than a genuine physical feature."],"supporting_citations":[{"why":"Introduces the ridge structure associated with a near-side jet, the starting point of the MKM.","marker":"[50]"},{"why":"Presents the momentum-kick description of the near-side ridge and jet quenching, laying out the kick formalism.","marker":"[51]"},{"why":"Extends the MKM to PHENIX ridge data and photon jets, establishing the parameter conventions used here.","marker":"[52]"},{"why":"Applies the MKM to pp collisions at 7 TeV, providing the earlier pp benchmark.","marker":"[53]"},{"why":"Applies the MKM to PbPb collisions at 2.76 TeV, the previous system-size test and source of parameter choices such as m_d.","marker":"[54]"},{"why":"Applies the MKM to high-multiplicity pp collisions at 13 TeV, the baseline whose T-fixing method this paper replaces with a free T.","marker":"[37]"},{"why":"Provides the ALICE 13 TeV high-multiplicity long-range correlation data fitted in Subsection 3.2.","marker":"[5]"},{"why":"Provides the CMS 13 TeV and 7 TeV high-multiplicity correlation data fitted in Subsection 3.2.","marker":"[31]"},{"why":"Provides the ATLAS 13 TeV correlation data used both as a cross-check and for the multiplicity-bin analysis.","marker":"[3]"}],"fun_headline_variants":["Kick-only model reproduces near-side ridge in pp collisions","Momentum-kick model fits pp ridge at 13 and 7 TeV","Single kick model explains pp ridge, predicts 14 TeV","Jet kicks reproduce pp ridge without QGP"],"cache_read_input_tokens":3200,"weakest_assumption_plain":"The load-bearing premise is that the model's parameters carry over between energies and multiplicities through two scaling rules—T scaling with mean transverse momentum and q inversely with multiplicity—rules inferred from a single comparison between 13 and 7 TeV; if either scaling is wrong, the 7 TeV fits, the multiplicity-bin description, and the 14 TeV prediction lose quantitative support even if the 13 TeV fits stand.","fun_headline_variants_meta":{"raw":{"variants":["Kick-only model reproduces near-side ridge in pp collisions","Momentum-kick model fits pp ridge at 13 and 7 TeV","Single kick model explains pp ridge, predicts 14 TeV","Jet kicks reproduce pp ridge without QGP"]},"model":"deepseek-v4-flash","effort":"low","cost_usd":0.001053,"raw_usage":{"total_tokens":4514,"prompt_tokens":1133,"completion_tokens":3381,"prompt_tokens_details":{"cached_tokens":384},"prompt_cache_hit_tokens":384,"prompt_cache_miss_tokens":749,"completion_tokens_details":{"reasoning_tokens":3309}},"tokens_in":749,"tokens_out":3381,"duration_ms":24893,"temperature":1.0,"reasoning_tokens":3309,"cache_read_input_tokens":384,"cache_creation_input_tokens":0},"cache_creation_input_tokens":0},"created_at":"2026-08-12T13:56:30.813705+00:00","model_set":{"reader":"deepseek-v4-flash"},"falsifier":"Compare the MKM's published 14 TeV prediction, with its ±10% parameter band (q≈1.075, T≈1.193, f_R⟨N_k⟩≈2.310), to the measured long-range near-side Δφ correlation in high-multiplicity pp collisions from LHC Run 3; a data point falling outside that band, or a peak position and width that deviate from the predicted shape, would falsify the energy scaling used to extend the model.","supporting_citations":[{"cited_title":"Ridge structure in the∆ϕ−∆ηcorrelation func- tion associated with a near-side jet","cited_arxiv_id":null,"evidence_quote":"Introduces the ridge structure associated with a near-side jet, the starting point of the MKM."},{"cited_title":"Momentum kick model description of the near-side ridge and jet quenching","cited_arxiv_id":null,"evidence_quote":"Presents the momentum-kick description of the near-side ridge and jet quenching, laying out the kick formalism."},{"cited_title":"Momentum kick model analysis of phenix near-side ridge data and photon jet","cited_arxiv_id":null,"evidence_quote":"Extends the MKM to PHENIX ridge data and photon jets, establishing the parameter conventions used here."},{"cited_title":"Momentum-kick model description of the ridge in ∆φ-∆ηcorrelations inppcollisions at 7 tev","cited_arxiv_id":null,"evidence_quote":"Applies the MKM to pp collisions at 7 TeV, providing the earlier pp benchmark."},{"cited_title":"Application of the momentum kick model to pbpb colli- sions at √sNN =2.76tevat the lhc","cited_arxiv_id":null,"evidence_quote":"Applies the MKM to PbPb collisions at 2.76 TeV, the previous system-size test and source of parameter choices such as m_d."},{"cited_title":"Momentum-kick model application to high- multiplicity pp collisions at √s=13tev at the lhc","cited_arxiv_id":null,"evidence_quote":"Applies the MKM to high-multiplicity pp collisions at 13 TeV, the baseline whose T-fixing method this paper replaces with a free T."},{"cited_title":"Long- and short-range correlations and their event-scale dependence in high-multiplicity pp collisions at $\\boldsymbol{\\sqrt{{\\textit s}}}=13$ TeV","cited_arxiv_id":"2101.03110","evidence_quote":"Provides the ALICE 13 TeV high-multiplicity long-range correlation data fitted in Subsection 3.2."}],"review_version":1}