REVIEW
Evidence of partonic collectivity in OO collisions through the measurement of $\phi$, K$^0_{\rm S}$, and $\Lambda$ elliptic flow
Nuclear Experiment · Submitted 26 Oct 2026 · 36 references
Pith's verdict: First phi meson v2 in small system, clean measurement with robust conclusion; minor non-flow systematics are tested and do not undermine the result.
Why Pith says this
Highlight any text to comment on it.
Referee report
The paper
The paper claims
First measurement of phi meson elliptic flow in oxygen-oxygen collisions shows mass ordering at low pT and baryon-meson splitting at intermediate pT, with phi following K0S rather than Lambda, supporting quark recombination from a collectively flowing partonic medium.
The reading
Extended reading notes
Core claim
The phi meson elliptic flow in OO collisions follows the same trend as the lighter K0S meson, not the similarly massive Lambda baryon, disfavoring a purely mass-driven interpretation and supporting hadronization via quark recombination from a collectively flowing partonic medium. The paper states: 'The φ meson behavior disfavors a purely mass-driven interpretation of the observed patterns and supports the role of hadronization via quark recombination from a collectively flowing partonic medium.'
Load-bearing premise
The low-multiplicity template fit method correctly removes non-flow correlations after the pseudorapidity gap selection (|Δη| > 1.2). The residual non-flow contribution is parameterized by scaling a low-multiplicity (65-100%) reference distribution, and the method assumes that the shape of non-flow correlations does not change significantly between low and high multiplicity events. The paper tests this assumption by varying the gap width and the low-multiplicity reference definition, but any residual non-flow could systematically affect the measured v2 values, especially at high pT where the non-flow systematic uncertainty reaches up to 9%.
Original abstract
The first measurement of the elliptic-flow coefficient ($v_{2}$) of $\phi$, K$^0_{\rm S}$, and $\Lambda (\overline{\Lambda})$ hadrons performed in OO collisions at $\sqrt{s_{\mathrm{NN}}}=5.36$ TeV with the ALICE detector is presented as a function of transverse momentum ($p_{\rm T}$) in central and semi-central collisions. For the $\phi$ meson, in particular, this is the first measurement of the elliptic flow in a small collision system. At low $p_{\rm T}$, a characteristic mass ordering of $v_{2}$ is observed, consistent with collective expansion of the system, in which heavier hadrons are shifted to higher $p_{\rm T}$ by a common velocity field. At intermediate $p_{\rm T}$, above 3 GeV/$c$, a baryon$-$meson splitting with a $10\sigma$ significance emerges, with the $\Lambda (\overline{\Lambda})$ baryon exhibiting larger $v_{2}$ values than mesons, while, despite its mass being close to the mass of the $\Lambda$, the $\phi$ follows the K$^{0}_{\rm S}$. The $\phi$ meson behavior disfavors a purely mass-driven interpretation of the observed patterns and supports the role of hadronization via quark recombination from a collectively flowing partonic medium. These results provide complementary evidence that key signatures of partonic collectivity observed in Pb$-$Pb collisions persist in light nucleus$-$nucleus systems.
The compiled record
The paper's own sentences, arranged, kept beside the review and separate from it. Each label is drawn from a closed vocabulary; the number beside it is the probability the classifier gave that label. Numbers in the tables are the authors', checked by code. No sentence in this record was written by a model.
The abstract, sentence by sentence
The first measurement of the elliptic-flow coefficient ($v_{2}$) of $\phi$, K$^0_{\rm S}$, and $\Lambda (\overline{\Lambda})$ hadrons performed in OO collisions at $\sqrt{s_{\mathrm{NN}}}=5.36$ TeV with the ALICE detector is presented as a function of transverse momentum ($p_{\rm T}$) in central and semi-central collisions. For the $\phi$ meson, in particular, this is the first measurement of the elliptic flow in a small collision system. At low $p_{\rm T}$, a characteristic mass ordering of $v_{2}$ is observed, consistent with collective expansion of the system, in which heavier hadrons are shifted to higher $p_{\rm T}$ by a common velocity field. At intermediate $p_{\rm T}$, above 3 GeV/$c$, a baryon$-$meson splitting with a $10\sigma$ significance emerges, with the $\Lambda (\overline{\Lambda})$ baryon exhibiting larger $v_{2}$ values than mesons, while, despite its mass being close to the mass of the $\Lambda$, the $\phi$ follows the K$^{0}_{\rm S}$. The $\phi$ meson behavior disfavors a purely mass-driven interpretation of the observed patterns and supports the role of hadronization via quark recombination from a collectively flowing partonic medium. These results provide complementary evidence that key signatures of partonic collectivity observed in Pb$-$Pb collisions persist in light nucleus$-$nucleus systems.
background contribution method result interpretation main claim
| # | sentence | role | the authors' own work | states the main conclusion | strength |
|---|---|---|---|---|---|
| s0 | The first measurement of the elliptic-flow coefficient ($v_{2}$) of $\phi$, K$^0_{\rm S}$, and $\Lambda (\overline{\Lambda})$ hadrons performed in OO collisions at $\sqrt{s_{\mathrm{NN}}}=5.36$ TeV with the ALICE detector is presented as a function of transverse momentum ($p_{\rm T}$) in central and semi-central collisions. | contribution 0.99 | 0.97 | 0.05 | asserted 1.00 |
| s1 | For the $\phi$ meson, in particular, this is the first measurement of the elliptic flow in a small collision system. | contribution 0.70 | 0.89 | 0.05 | asserted 1.00 |
| s2 | At low $p_{\rm T}$, a characteristic mass ordering of $v_{2}$ is observed, consistent with collective expansion of the system, in which heavier hadrons are shifted to higher $p_{\rm T}$ by a common velocity field. | result 0.96 | 0.92 | 0.08 | hedged possibility 0.58 |
| s3 | At intermediate $p_{\rm T}$, above 3 GeV/$c$, a baryon$-$meson splitting with a $10\sigma$ significance emerges, with the $\Lambda (\overline{\Lambda})$ baryon exhibiting larger $v_{2}$ values than mesons, while, despite its mass being close to the mass of the $\Lambda$, the $\phi$ follows the K$^{0}_{\rm S}$. | result 1.00 | 0.95 | 0.12 | asserted 1.00 |
| s4 | The $\phi$ meson behavior disfavors a purely mass-driven interpretation of the observed patterns and supports the role of hadronization via quark recombination from a collectively flowing partonic medium. | interpretation 1.00 | 0.83 | 0.36 | asserted 0.64 |
| s5 | These results provide complementary evidence that key signatures of partonic collectivity observed in Pb$-$Pb collisions persist in light nucleus$-$nucleus systems. | interpretation 0.98 | 0.74 | 0.82 | asserted 0.80 |
What was examined, and what was not
- arXiv listing abstract v1
- full text
- figures and tables
- references and citing sentences
- relations to other papers
- P abstract
- S sections
- T body sentences
- C citations
- R cross-paper relations
Figures
Figures reproduced from arXiv:2610.36237 by the authors.
References
Discussion
Disagree with the review, or know something it missed? Leave a comment, highlight any passage above to comment on it, or challenge this review formally.