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arXiv · 2510.02580

Observation of long-range collective flow in OO and NeNe collisions and implications for nuclear structure studies

CMS Collaboration
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Abstract

The long-range collective flow of particles produced in oxygen-oxygen (OO) and neon-neon (NeNe) collisions is measured with the CMS detector at the CERN LHC. The data samples were collected at a center-of-mass energy per nucleon pair of 5.36 TeV, with integrated luminosities of 7 nb$^{-1}$ and 0.8 nb$^{-1}$ for OO and NeNe collisions, respectively. Two- and four-particle azimuthal correlations are measured over nearly five units of pseudorapidity. Significant elliptic ($v_2$) and triangular ($v_3$) flow harmonics are observed in both systems. The ratios of $v_n$ coefficients between NeNe and OO collisions suggest sensitivity to the intrinsic nuclear structure of the respective Ne and O ions. Hydrodynamic models with $\textit{ab initio}$ nuclear structure inputs qualitatively reproduce the collision-overlap dependence of both the $v_n$ values and the NeNe to OO ratios. These measurements provide new constraints when modeling the interplay of nuclear structure and collective dynamics in collisions of $^{16}$O and $^{20}$Ne, respectively.

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CMS Collaboration. 2025-10-02. Observation of long-range collective flow in OO and NeNe collisions and implications for nuclear structure studies. https://doi.org/10.1103/26wx-tg6f

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