This paper presents the first measurements of the azimuthal anisotropy coefficients vn, which quantify the nth-order Fourier modulation of charged-particle azimuthal distributions, for n = 2−4 in root sNN = 5.36 TeV 16O+16O and 20Ne+20Ne collisions recorded with the ATLAS detector at the CERN Large Hadron Collider in 2025. The vn coefficients are measured as a function of transverse momentum (pT), collision centrality, and event multiplicity. They are extracted using two complementary methods: two-particle correlations with a template-fit subtraction of short-range nonflow contributions, and four-particle subevent cumulants, which intrinsically suppress nonflow effects and provide sensitivity to flow fluctuations. The results show a clear hierarchy v2 > v3 > v4 and a nonmonotonic dependence on pT, reaching a maximum around 2 GeV, consistent with trends observed in heavy-ion collisions. Detailed comparisons between the two collision systems reveal an enhanced v2 in central 20Ne+20Ne collisions, consistent with theory expectations based on the predicted prolate deformation of neon nuclei, in contrast to the slightly tetrahedral structure predicted for oxygen. The four-particle cumulant results highlight strong event-by-event fluctuations and provide the greatest sensitivity to nuclear shape effects. These measurements can place new constraints on the initial geometry and the hydrodynamic response in light-ion collisions, offering valuable input for models of nuclear structure.

Aad, G., Aakvaag, E., Abbott, B., Abdelhameed, S., Abeling, K., Abicht, N.j., et al. (2026). Measurement of the azimuthal anisotropy of charged particles in root sNN = 5.36 TeV 16O + 16O and 20Ne + 20Ne collisions with the ATLAS detector. PHYSICAL REVIEW C, 113(4) [10.1103/xqxz-8bhf].

Measurement of the azimuthal anisotropy of charged particles in root sNN = 5.36 TeV 16O + 16O and 20Ne + 20Ne collisions with the ATLAS detector

Aielli, G.;Camarri, P.;Cerrito, L.;De Sanctis, U.;Di Ciaccio, A.;
2026-01-01

Abstract

This paper presents the first measurements of the azimuthal anisotropy coefficients vn, which quantify the nth-order Fourier modulation of charged-particle azimuthal distributions, for n = 2−4 in root sNN = 5.36 TeV 16O+16O and 20Ne+20Ne collisions recorded with the ATLAS detector at the CERN Large Hadron Collider in 2025. The vn coefficients are measured as a function of transverse momentum (pT), collision centrality, and event multiplicity. They are extracted using two complementary methods: two-particle correlations with a template-fit subtraction of short-range nonflow contributions, and four-particle subevent cumulants, which intrinsically suppress nonflow effects and provide sensitivity to flow fluctuations. The results show a clear hierarchy v2 > v3 > v4 and a nonmonotonic dependence on pT, reaching a maximum around 2 GeV, consistent with trends observed in heavy-ion collisions. Detailed comparisons between the two collision systems reveal an enhanced v2 in central 20Ne+20Ne collisions, consistent with theory expectations based on the predicted prolate deformation of neon nuclei, in contrast to the slightly tetrahedral structure predicted for oxygen. The four-particle cumulant results highlight strong event-by-event fluctuations and provide the greatest sensitivity to nuclear shape effects. These measurements can place new constraints on the initial geometry and the hydrodynamic response in light-ion collisions, offering valuable input for models of nuclear structure.
2026
Pubblicato
Rilevanza internazionale
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Esperti anonimi
Settore PHYS-01/A - Fisica sperimentale delle interazioni fondamentali e applicazioni
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Con Impact Factor ISI
Aad, G., Aakvaag, E., Abbott, B., Abdelhameed, S., Abeling, K., Abicht, N.j., et al. (2026). Measurement of the azimuthal anisotropy of charged particles in root sNN = 5.36 TeV 16O + 16O and 20Ne + 20Ne collisions with the ATLAS detector. PHYSICAL REVIEW C, 113(4) [10.1103/xqxz-8bhf].
Aad, G; Aakvaag, E; Abbott, B; Abdelhameed, S; Abeling, K; Abicht, Nj; Abidi, Sh; Aboelela, M; Aboulhorma, A; Abramowicz, H; Abulaiti, Y; Acharya, Bs;...espandi
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2108/462606
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