Role of clustered nuclear geometry in particle production through p–C and p–O collisions at the Large Hadron Collider

Abstract

Long-range multi-particle correlations in heavy-ion collisions have shown conclusive evidence of the hydrodynamic behavior of strongly interacting matter and are associated with the final-state azimuthal momentum anisotropy. In small collision systems, azimuthal anisotropy can be influenced by the hadronization mechanism and residual jet-like correlations. Thus, one of the motives of the planned p–O and O–O collisions at the LHC and RHIC is to understand the origin of small system collectivity. As the anisotropic flow coefficients (vn) are sensitive to the initial-state effects including nuclear shape, deformation, and charge density profiles, studies involving 12C and 16O nuclei are transpiring due to the presence of exotic α (4He) clusters in such nuclei. In this study, for the first time, we investigate the effects of nuclear α–clusters on the azimuthal anisotropy of the final-state hadrons in p–C and p–O collisions at sNN=9.9 TeV within a multi-phase transport model framework. We report the transverse momentum (pT) and pseudorapidity (η) spectra, participant eccentricity (ϵ2) and triangularity (ϵ3), and estimate the elliptic flow (v2) and triangular flow (v3) of the final-state hadrons using the two-particle cumulant method. These results are compared with a model-independent Sum of Gaussians (SOG) type nuclear density profile for 12C and 16O nuclei. © The Author(s), under exclusive licence to Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature 2025.