Constraining $\alpha$-cluster compactness in ${}^{16}\mathrm{O}$ and ${}^{20}\mathrm{Ne}$ at TeV energies using azimuthal anisotropy

Abstract

Anisotropic flow in ultra-relativistic light-ion collisions is sensitive to the initial geometry of the colliding nuclei. We investigate whether elliptic flow measurements can constrain the parameters of the proposed $\alpha$-clustered nuclear density distributions of ${}^{16}$O and ${}^{20}$Ne at LHC energies. Using the hybrid framework IP-Glasma+MUSIC+iSS+UrQMD, we simulate OO and Ne--Ne collisions at $\sqrt{s_{\mathrm{NN}}}=5.36$ TeV for the Woods--Saxon and $\alpha$-clustered configurations with varying cluster compactness. The elliptic flow coefficient $v_2\{2,|\Delta \eta |>1\}$ is calculated in the kinematic acceptances of ALICE, CMS, and ATLAS detectors and is compared with the Run~3 OO and Ne--Ne experimental measurements. It is observed that the final-state elliptic flow is significantly sensitive to the nuclear geometry, especially in OO collisions, where different configurations lead to distinct centrality dependencies and peak positions of $v_2$. By performing a systematic variation of the cluster size and inter-cluster separation in ${}^{16}$O and ${}^{20}$Ne nuclei, this work attempts to identify the cluster parameter range that provides the best agreement with the experimental data. These results show that the flow observables in TeV-energy light-ion collisions can be used to optimize the nuclear structure parameters of light nuclei.

Comments: 9 pages, 4 captioned figures, submitted for publication