Pith. sign in

REVIEW 3 major objections 4 minor 56 references

String-shoving simulations place the strongest ultra-long-range ridge at the lowest pp multiplicities.

Reviewed by Pith at T0; open to challenge. T0 means a machine referee read the full paper against a public rubric. the ladder, T0–T4 →

T0 review · deepseek-v4-flash

2026-08-03 17:27 UTC pith:JHY6MZP3

load-bearing objection Low-MPI dijets carry the real ridge signal; the claimed high-multiplicity failure of string shoving is muddied by the template-fit subtraction. the 3 major comments →

arxiv 2512.09195 v2 pith:JHY6MZP3 submitted 2025-12-09 hep-ph

Finite V_(rm 2Delta) puzzle in low-multiplicity pp collisions from ultra-long-range azimuthal correlations in the string-shoving model

classification hep-ph
keywords string shovingridge correlationslow-multiplicity pp collisionsV2Δtemplate fitflattenicitymultiparton interactionscollectivity
verification ladder T0 review T1 audit T2 compute T3 formal T4 reserved

The pith

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

This paper argues that the string-shoving mechanism in PYTHIA8 can produce a non-zero elliptic-flow coefficient V2Δ at ultra-long pseudorapidity separations, and that its signature should be most visible in the sparsest proton-proton collisions — events with only one or a few parton-parton scatterings. The authors show that V2Δ decreases with increasing charged-particle multiplicity, opposite to the weak multiplicity dependence seen in LHC data, and they connect this tension to biases in the template-fit method and in N_ch-based event selection. If correct, the low-multiplicity ridge in pp collisions need not signal a thermalized quark-gluon plasma; repulsive interactions among a few overlapping color strings could be enough. The paper also advocates replacing N_ch with global event-topology estimators such as flattenicity to obtain cleaner comparisons with data.

Core claim

Using PYTHIA8 with the string-shoving mechanism, the authors find that the second-order two-particle correlation coefficient V2Δ measured at 5<|Δη|<6 is largest in the lowest-multiplicity event classes, particularly for N_mpi≈1 dijet events, and declines monotonically as N_ch increases. This stands in contrast to LHC data, which show only a weak multiplicity dependence. They trace the model's decreasing trend to three effects: random cancellation of many small string pushes, dilution of a fixed anisotropic momentum over more particles, and an over-subtraction in the template-fit method because the low-multiplicity reference already contains flow-like correlations. The paper concludes that st

What carries the argument

The string-shoving mechanism: repulsive transverse pressure between overlapping color strings in PYTHIA8 that generates a collective push and mimics flow without a quark-gluon plasma. The extraction uses the template-fit method, which assumes high-multiplicity events are a scaled low-multiplicity 'non-flow' reference plus an additional Fourier term; V2Δ is read off the n=2 coefficient. The event-activity estimators N_ch (midrapidity charged multiplicity), N_mpi (number of parton-parton scatterings), and flattenicity (an event-shape variable measuring multiplicity fluctuations across V0-like cells) serve as alternative classifiers.

Load-bearing premise

The template-fit method assumes the low-multiplicity reference contains no genuine long-range flow; the paper itself shows that the string-shoving low-multiplicity template already carries flow-like correlations, so subtracting it can artificially suppress V2Δ at higher multiplicities.

What would settle it

If experimental analyses using an event-shape estimator like flattenicity (which the paper argues is less biased) were to show V2Δ increasing or flat with activity, the string-shoving prediction of a decreasing trend would be contradicted. Alternatively, a simulation with string shoving that uses a low-multiplicity template with flow explicitly removed (e.g., from a non-shoving baseline) should yield a flatter V2Δ(N_ch) if the over-subtraction explanation is correct.

Watch this falsifier. Get emailed when new claim-graph text bears on it.

If this is right

  • If string shoving is right, the low-multiplicity ridge observed in pp collisions does not require quark-gluon plasma formation.
  • N_ch-based event selection artificially dilutes the collective signal, so studies comparing models and data should use global estimators like flattenicity.
  • String shoving has a built-in saturation: it fades in dense, isotropic environments, consistent with a gradual onset of collectivity where hydrodynamics becomes relevant at high multiplicity.
  • The decreasing V2Δ trend in the model is partly an artifact of over-subtraction, so template-fit results should be reinterpreted with a flow-free reference.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • If flattenicity-based event classes are adopted in future LHC measurements, the data may show a stronger multiplicity dependence than the N_ch-based results, providing a direct test of the string-shoving contribution at low multiplicities.
  • The over-subtraction mechanism described here could also affect other small-system ridge studies that use template fits, suggesting a systematic re-analysis of existing low-multiplicity ridge data with alternative non-flow references.
  • The finding that dijet events produce the strongest shoving signal implies that jets may seed the geometry for collective-like correlations, connecting the ridge to jet fragmentation in a way that can be studied with jet-triggered correlations.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit.

Referee Report

3 major / 4 minor

Summary. This paper uses PYTHIA8 (v8.312, string-shoving extension, g=10) to compute the second-order two-particle correlation V2Δ for |Δη| in [5,6] in pp collisions at 13 TeV, studying its dependence on three event-activity estimators: midrapidity Nch, generator-level Nmpi, and flattenicity. The template-fit method is used to extract V2Δ from Δφ projections. The authors report that V2Δ decreases with Nch, while ALICE data show a much weaker multiplicity dependence; that the raw correlation is strongest for the lowest-Nmpi (dijet-like) event class, contrary to the usual high-multiplicity collectivity picture; and that Nch is more biased toward jet-like topologies than Nmpi or flattenicity. They conclude that string shoving may explain the low-multiplicity ridge and that hydrodynamics becomes relevant only at high multiplicity.

Significance. If the quantitative result were robust, this would be a valuable constraint on the origin of collectivity in small systems: it would demonstrate that a non-fluid, initial-state mechanism can generate ultra-long-range azimuthal correlations specifically in low-multiplicity events, and that the event-activity estimator is not a neutral choice. The paper is transparent in listing its PYTHIA parameters (Table I) and in scanning the shoving strength g (Fig. 5), which makes the model dependence of the signal falsifiable. The main weakness is that the central V2Δ(Nch) trend rests on a template subtraction whose low-multiplicity reference is shown by the authors themselves to contain long-range flow-like correlations; no matched no-shoving control or closure test is provided. The low-Nmpi ridge is visible in raw yields, so that part of the conclusion is less affected, but the quantitative model-data comparison and the 'hydro becomes relevant at high multiplicity' inference are not cleanly established.

major comments (3)
  1. [Sec. III (Fig. 2), Eq. (2), Summary item 5] The central evidence for a decreasing V2Δ(Nch) trend is the template-fit extraction in Fig. 1. Equation (2) requires the low-multiplicity template Y^LM to contain no genuine long-range correlation. The paper demonstrates otherwise: the string-shoving LM template already contains flow-like correlations, which are then subtracted from all higher Nch classes (Sec. III, Fig. 2 discussion; Summary item 5). This over-subtraction can produce the decreasing trend by construction. The Monash-LM-template check in Fig. 2 is not a matched control: Monash differs in tune, hadronization, and non-flow shape from the string-shoving sample, so it does not isolate the shoving effect. I acknowledge that the low-Nmpi ridge is visible in raw yields (Fig. 4) and is therefore independent of the template subtraction; my concern is specifically the quantitative V2Δ(Nch) trend and its interpretation as evidence a
  2. [Sec. II.B and Figs. 1-4] No statistical or systematic uncertainties are reported for the PYTHIA V2Δ values, and no closure test of the template fit is provided. The model-data differences that drive the conclusions are at the level of V2Δ ~ 0.0005–0.002 (Figs. 1-2), so without error bars it is unclear whether the quoted trends are significant relative to stochastic fluctuations. A closure test, in which a known V2Δ is injected into the signal class and recovered by Eq. (2), is especially important given that the reference itself contains long-range correlations. Even with 10 billion events, systematic uncertainties from the choice of template and event-class boundaries must be quantified before comparing to ALICE data.
  3. [Sec. II.C, Eq. (3), and Fig. 4] The recommendation that flattenicity is a better estimator than Nch is only partly supported by the presented evidence. Flattenicity was constructed in Ref. [36] to select MPI-dominated, topologically isotropic events, so the statement that it reduces Nch-type bias is, to some extent, built into its definition. More importantly, the comparison in Fig. 4 is between classifiers acting on different acceptances: Nch is midrapidity, while flattenicity is built from V0-like cell multiplicities that overlap the forward/backward intervals used to construct V2Δ (2.6<η<3.2 and -3.0<η<-2.0). This overlap can introduce an autocorrelation in the flattenicity-selected per-trigger yields. To make the claim robust, the authors should quantify the acceptance overlap or repeat the flattenicity definition using a disjoint acceptance and show that the conclusions are unchanged.
minor comments (4)
  1. [Table II] The table header says 'Flattenicity Range' but the text says the reported quantity is 1-ρ_nch. Please state explicitly in the table/caption whether the ranges refer to 1-ρ_nch or ρ_nch, since the values (0.00–0.78, etc.) are hard to interpret otherwise.
  2. [Figs. 1-2] The figure legends are incomplete in the printed text: the hydro band in Fig. 1 is mentioned in the caption but no legend entry is visible in the figure itself. Please also state in the captions that the PYTHIA points carry no uncertainty bars.
  3. [Sec. II.B, Eq. (1)-(2)] Equation (2) omits the explicit |Δη| integration; please state clearly that the fit is applied to the Δφ projection integrated over 5.0<|Δη|<6.0, as described in the text, so that the notation is self-contained.
  4. [References] Refs. [34] and [41] appear to refer to the same paper (Bierlich, Gustafson, Lönnblad, JHEP 10 (2016) 139 / arXiv:1612.05132). Please consolidate to avoid duplicate citations.

Circularity Check

0 steps flagged

No load-bearing circularity: the template-fit over-subtraction is acknowledged and partly controlled; the main claim is anchored by external ALICE data and by raw correlation structures.

full rationale

The central derivation is a Monte Carlo comparison rather than a first-principles chain: PYTHIA8 with string shoving is run with fixed parameters (g=10), per-trigger yields are computed directly, and the extracted V2Δ(Nch) is compared to ALICE data and to a hydrodynamic calculation. No parameter is fitted to the target V2Δ data and then renamed as a prediction. The one caveat that could look definitional — Eq. (2) defines V2Δ as the excess over a scaled low-multiplicity template Y^LM, and the paper admits that the string-shoving LM template already contains flow-like correlations, causing over-subtraction (Sec. III, Fig. 2 discussion; Summary item 5) — is explicitly acknowledged and is not the sole basis for the conclusion. The same section shows that using a Monash (non-flow) LM template still yields a decreasing V2Δ(Nch) ('the trend is still decreasing'), so the decreasing trend is not generated purely by the contaminated reference. The low-Nmpi sensitivity and the g-dependence of the ridge are also taken directly from raw Δφ distributions, independent of the template subtraction. The flattenicity recommendation cites the authors' prior work [36] for the estimator's design goal, but the paper's own new simulations (Figs. 3–4) and the external ALICE benchmark carry the argument; the self-citation is therefore not load-bearing. Overall, the paper is self-contained and benchmarked against external data; no circular reduction of a predicted quantity to a fitted input or self-citation chain is identifiable.

Axiom & Free-Parameter Ledger

5 free parameters · 5 axioms · 0 invented entities

The central claims rest on the string-shoving model and on template-fit/event-classifier assumptions. No new physical entities are introduced; flattenicity is borrowed from the authors' prior work. The model parameters (g, r0, deltay, proton radius) are set from prior tunes, and F/G are fitted per class in the analysis.

free parameters (5)
  • Ropewalk:gAmplitude (g) = 10 (g=3 and g=40 explored)
    String-shoving repulsion strength; chosen by hand as 'conservative', not fit to ALICE data. Conclusions are g-dependent at low Nmpi (Fig. 5).
  • Ropewalk:r0 = 0.41
    Transverse string radius in the shoving model; adopted from model defaults, not varied or fit here.
  • Ropewalk:deltay = 0.10
    Longitudinal step for shoving; model input, not varied.
  • PartonVertex:ProtonRadius = 0.70
    Proton radius used for parton vertices; model input.
  • Template-fit F and G = per event class
    Scaling factors in Eq. (2) fitted by chi-square to each Δφ projection; the extracted V2Δ depends on the choice of LM reference (string-shoving vs Monash).
axioms (5)
  • domain assumption String shoving model: overlapping color strings repel via gluon exchange, producing transverse collective push.
    Underlying mechanism under test; assumed by PYTHIA8 Ropewalk and by the interpretation of the low-Nmpi ridge (Sec. II.A, III).
  • domain assumption Template-fit ansatz (Eq. 2): high-multiplicity Δφ yield = F × low-multiplicity yield + G(1+Σ2VnΔ cos nΔφ), with flow-free LM reference.
    Used to extract V2Δ; the paper notes the LM reference from string shoving already contains flow, violating the flow-free assumption (Sec. II.B, III).
  • domain assumption Ultra-long-range |Δη|>5 correlations on the near side are free of jet/resonance non-flow.
    Central to claiming the ridge is not from jet fragmentation; stated in Sec. II.B.
  • domain assumption Flattenicity (Eq. 3) in the V0 acceptance is a valid proxy for MPI activity / global event topology.
    Adopted from the authors' prior work (Refs. [36,47]); the paper's recommendation to prefer flattenicity over Nch relies on this.
  • domain assumption PYTHIA8 Monash tune provides a baseline with negligible long-range flow, usable as a pure non-flow template.
    Used in Fig. 2 to construct an alternative LM template; if Monash also contains residual flow, the subtraction is again biased (Sec. III, Fig. 2).

pith-pipeline@v1.3.0-alltime-deepseek · 12899 in / 15328 out tokens · 142917 ms · 2026-08-03T17:27:24.370187+00:00 · methodology

0 comments
read the original abstract

Ultra-long range angular correlations have been recently reported by the ALICE collaboration in pp collisions at $\sqrt{s}=13$ TeV below ${\rm d}N_{\rm ch}/{\rm d}\eta=7$. The measurements have been performed as a function of the charged-particle multiplicity at midrapidity ($N_{\rm ch}$ in $|\eta|<0.8$), which is known to be strongly sensitive to local multiplicity fluctuations. The present work investigates the impact of the event-activity estimator on ultra-long range angular correlations. The study is conducted in the framework of PYTHIA8 with the string shoving mechanism since it gives a non-zero elliptic flow coefficient, $V_{2\Delta}$. The analysis is conducted as a function of $N_{\rm ch}$, the number of parton-parton scatterings ($N_{\rm mpi}$) and flattenicity. Surprisingly, for ultra-long range correlations, pp collisions with $N_{\rm mpi}=1$ (dijets) seems to be the most sensitive to string shoving. The effect diminishes with increasing $N_{\rm mpi}$. While in data, within uncertainties, $V_{2\Delta}$ exhibits a weak multiplicity dependence; the string shoving mechanism gives a $V_{2\Delta}$ that decreases with the increase in $N_{\rm ch}$. The present work therefore supports the picture stating that mechanisms such as string shoving might explain the low multiplicity limit, whereas, hydro becomes relevant in high-multiplicity pp collisions. This work also suggests that flattenicity might be more effective than $N_{\rm ch}$ to better handle non-flow effects.

Figures

Figures reproduced from arXiv: 2512.09195 by Antonio Ortiz, Dushmanta Sahu, Gyula Bencedi.

Figure 1
Figure 1. Figure 1: FIG. 1. The [PITH_FULL_IMAGE:figures/full_fig_p005_1.png] view at source ↗
Figure 2
Figure 2. Figure 2: FIG. 2. The [PITH_FULL_IMAGE:figures/full_fig_p005_2.png] view at source ↗
Figure 3
Figure 3. Figure 3: FIG. 3. The ultra-long range correlation per-triggered yield estimated as a function of ∆ [PITH_FULL_IMAGE:figures/full_fig_p007_3.png] view at source ↗
Figure 4
Figure 4. Figure 4: FIG. 4. The ultra-long range correlation per-triggered yield estimated as a function of ∆ [PITH_FULL_IMAGE:figures/full_fig_p008_4.png] view at source ↗
Figure 5
Figure 5. Figure 5: FIG. 5. The ultra-long range correlation per-triggered yield estimated as a function of ∆ [PITH_FULL_IMAGE:figures/full_fig_p009_5.png] view at source ↗

discussion (0)

Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.

Reference graph

Works this paper leans on

56 extracted references · 3 linked inside Pith

  1. [1]

    The string-shoving mechanism alone is insufficient 9 1 −0 1 2 3 4 0.062 0.063 0.064 ϕ Δ d η Δ /d pair N 2 d trig N 1/ : Class-I mpiNg = 3 g = 10 g = 40 = 13 TeV, PYTHIA8, String shoving spp,| < 6.0 ηΔ5.0 < |1 −0 1 2 3 4 0.0615 0.062 0.0625 0.063 0.0635 0.064 : Class-II mpiNg = 3 g = 10 g = 40 1 −0 1 2 3 4 0.0615 0.062 0.0625 0.063 0.0635 0.064 : Class-III...

  2. [2]

    In these dijet-dominated events, the anisotropic geometry of a few overlap- ping strings and beam remnants allows for an effi- cient collective push

    Contrary to the intuitive link between collectiv- ity and high activity, the string-shoving mechanism generates its strongest ultra-long-range correlations in events with a low number of multiparton inter- actions (N mpi ≈1–3). In these dijet-dominated events, the anisotropic geometry of a few overlap- ping strings and beam remnants allows for an effi- ci...

  3. [3]

    UsingN ch as an event-activity es- timator conflates events with genuine underlying- event activity and those with high particle yield from jets

    The traditional event classifierN ch introduces a sig- nificant bias. UsingN ch as an event-activity es- timator conflates events with genuine underlying- event activity and those with high particle yield from jets. This bias dilutes the collective signal and artificially exacerbates the decreasingV 2∆ trend, worsening the apparent failure of the model

  4. [4]

    Global event-shape estimators reveal the true model behavior. When using direct proxies for string density like the number of MPIs or the novel event-shape observable like flattenicity, the analysis shows that the string-shoving signal saturates and diminishes in dense, isotropic environments. This built-in saturation is a key feature of the mecha- nism

  5. [5]

    It is demonstrated that the low-multiplicity templates used for non-flow subtraction already contain sig- nificant flow-like correlations from string shoving

    The template fit method is further complicated by inherent flow-like effects in low-activity events. It is demonstrated that the low-multiplicity templates used for non-flow subtraction already contain sig- nificant flow-like correlations from string shoving. This leads to over-subtraction in higher activity classes, further suppressing the extractedV 2∆

  6. [6]

    The analysis results support a picture of a grad- ual onset of collectivity as a function of system size and density. In this picture, initial-state effects like string shoving dominate in low-multiplicity pp colli- sions, while final-state collective expansion (hydro- dynamics) becomes increasingly relevant in high- multiplicity pp collisions. In conclus...

  7. [7]

    Khachatryanet al.[CMS], JHEP04, 039 (2017)

    V. Khachatryanet al.[CMS], JHEP04, 039 (2017)

  8. [8]

    Acharyaet al.[ALICE], JHEP11, 013 (2018)

    S. Acharyaet al.[ALICE], JHEP11, 013 (2018)

  9. [9]

    B. B. Abelevet al.[ALICE], Phys. Lett. B728, 216 (2014) [erratum: Phys. Lett. B734, 409 (2014)]

  10. [10]

    Acharyaet al.[ALICE], Phys

    S. Acharyaet al.[ALICE], Phys. Lett. B849, 138451 (2024)

  11. [11]

    Chatrchyanet al.[CMS], JHEP07, 076 (2011)

    S. Chatrchyanet al.[CMS], JHEP07, 076 (2011)

  12. [12]

    Aamodtet al.[ALICE], Phys

    K. Aamodtet al.[ALICE], Phys. Lett. B708, 249 (2012)

  13. [13]

    J. Y. Ollitrault, Phys. Rev. D46, 229 (1992)

  14. [14]

    Voloshin and Y

    S. Voloshin and Y. Zhang, Z. Phys. C70, 665 (1996)

  15. [15]

    K. H. Ackermannet al.[STAR], Phys. Rev. Lett.86, 402 (2001)

  16. [16]

    Romatschke and U

    P. Romatschke and U. Romatschke, Phys. Rev. Lett.99, 172301 (2007)

  17. [17]

    Song and U

    H. Song and U. W. Heinz, Phys. Rev. C77, 064901 (2008)

  18. [18]

    Hirano and M

    T. Hirano and M. Gyulassy, Nucl. Phys. A769, 71 (2006)

  19. [19]

    Khachatryanet al.[CMS], Phys

    V. Khachatryanet al.[CMS], Phys. Lett. B765, 193 (2017)

  20. [20]

    Khachatryanet al.[CMS], Phys

    V. Khachatryanet al.[CMS], Phys. Rev. Lett.118, 122301 (2017)

  21. [21]

    Adamet al.[ALICE], Nature Phys.13, 535 (2017)

    J. Adamet al.[ALICE], Nature Phys.13, 535 (2017)

  22. [22]

    Acharyaet al.[ALICE], Eur

    S. Acharyaet al.[ALICE], Eur. Phys. J. C80, 693 (2020)

  23. [23]

    D. Sahu, S. Tripathy, R. Sahoo and S. K. Tiwari, Eur. Phys. J. A58, 78 (2022)

  24. [24]

    Sahu and R

    D. Sahu and R. Sahoo, J. Phys. G48, 125104 (2021)

  25. [25]

    A. N. Mishra, D. Sahu and R. Sahoo, MDPI Physics4, 315 (2022)

  26. [26]

    D. Sahu, S. Tripathy, R. Sahoo and A. R. Dash, Eur. Phys. J. A56, 187 (2020)

  27. [27]

    Scaria, D

    R. Scaria, D. Sahu, C. R. Singh, R. Sahoo and J. e. Alam, Eur. Phys. J. A59, 140 (2023)

  28. [28]

    Habich, G

    M. Habich, G. A. Miller, P. Romatschke and W. Xiang, Eur. Phys. J. C76, 408 (2016)

  29. [29]

    U. W. Heinz and J. S. Moreland, J. Phys. Conf. Ser. 1271, 012018 (2019)

  30. [30]

    Hatwar and M

    N. Hatwar and M. Mishra, Phys. Rev. C106, 054902 (2022)

  31. [31]

    Acharyaet al.[ALICE], [arXiv:2504.02359]

    S. Acharyaet al.[ALICE], [arXiv:2504.02359]

  32. [32]

    Vertesi and A

    R. Vertesi and A. Ortiz, Phys. Rev. D112, 036009 (2025)

  33. [33]

    Hayrapetyanet al.[CMS], Phys

    A. Hayrapetyanet al.[CMS], Phys. Rev. Lett.133, 142301 (2024)

  34. [34]

    Dusling, P

    K. Dusling, P. Tribedy and R. Venugopalan, Phys. Rev. D93, 014034 (2016)

  35. [35]

    W. Zhao, S. Ryu, C. Shen and B. Schenke, Phys. Rev. C 107, 014904 (2023)

  36. [36]

    Schenke, S

    B. Schenke, S. Schlichting and P. Singh, Phys. Rev. D 105, no.9, 094023 (2022)

  37. [37]

    Sjostrand, S

    T. Sjostrand, S. Mrenna and P. Z. Skands, Comput. Phys. Commun.178, 852 (2008)

  38. [38]

    Sj¨ ostrand, S

    T. Sj¨ ostrand, S. Ask, J. R. Christiansen, R. Corke, N. De- sai, P. Ilten, S. Mrenna, S. Prestel, C. O. Rasmussen and P. Z. Skands, Comput. Phys. Commun.191, 159 (2015)

  39. [39]

    Bierlich, G

    C. Bierlich, G. Gustafson and L. L¨ onnblad, Phys. Lett. B779, 58 (2018)

  40. [40]

    Bierlich, G

    C. Bierlich, G. Gustafson and L. L¨ onnblad, JHEP10, 139 (2016)

  41. [41]

    Bierlich, Universe10, 46 (2024)

    C. Bierlich, Universe10, 46 (2024)

  42. [42]

    Ortiz, A

    A. Ortiz, A. Khuntia, O. V´ azquez-Rueda, S. Tripathy, G. Bencedi, S. Prasad and F. Fan, Phys. Rev. D107, 076012 (2023)

  43. [43]

    Bierlich, G

    C. Bierlich, G. Gustafson, L. L¨ onnblad and H. Shah, JHEP10, 134 (2018)

  44. [44]

    Andersson, G

    B. Andersson, G. Gustafson, G. Ingelman and T. Sjos- trand, Phys. Rept.97, 31 (1983)

  45. [45]

    Sjostrand, Comput

    T. Sjostrand, Comput. Phys. Commun.27, 243 (1982)

  46. [46]

    Skands, S

    P. Skands, S. Carrazza and J. Rojo, Eur. Phys. J. C74, 3024 (2014)

  47. [47]

    Bierlich, G

    C. Bierlich, G. Gustafson and L. L¨ onnblad, [arXiv:1612.05132]

  48. [48]

    Aadet al.[ATLAS], Phys

    G. Aadet al.[ATLAS], Phys. Rev. Lett.116, 172301 (2016)

  49. [49]

    B. B. Abelevet al.[ALICE], Phys. Lett. B726, 164 (2013)

  50. [50]

    Chatrchyanet al.[CMS], Phys

    S. Chatrchyanet al.[CMS], Phys. Lett. B718, 795 (2013)

  51. [51]

    J. E. Mu˜ noz M´ endez and A. Ortiz, J. Phys. G52, 095001 (2025)

  52. [52]

    Ortiz Velasquez, P

    A. Ortiz Velasquez, P. Christiansen, E. Cuautle Flores, I. Maldonado Cervantes and G. Pai´ c, Phys. Rev. Lett. 111, 042001 (2013)

  53. [53]

    Acharyaet al.[ALICE], Phys

    S. Acharyaet al.[ALICE], Phys. Rev. D111, 012010 (2025)

  54. [54]

    J. Kim, E. J. Kim, S. Ji and S. Lim, J. Korean Phys. Soc.79, no.5, 447 (2021)

  55. [55]

    Bierlich, Nucl

    C. Bierlich, Nucl. Phys. A982, 499 (2019)

  56. [56]

    J. F. Grosse-Oetringhaus and U. A. Wiedemann, [arXiv:2407.07484 [hep-ex]]