Speaker
Description
In heavy-ion collisions, collective flow arises from the response of the produced medium to the initial-state geometry. Measurements of azimuthal particle correlations provide powerful tools to investigate the emergence of collective behaviour, the transport properties of hot QCD matter, and the role of nuclear geometry in the initial state. The LHCb experiment offers unique capabilities for such studies through its forward rapidity coverage and its dedicated fixed-target programme. This contribution presents recent LHCb measurements of collective flow in collider and fixed-target heavy-ion collisions.
Measurements of azimuthal particle correlations in PbPb and pPb collisions at forward rapidity allow the longitudinal structure of collective phenomena to be investigated in a kinematic region not covered by other LHC experiments. Comparisons between forward and backward rapidity regions in asymmetric collision systems further provide sensitivity to the mechanisms driving collectivity in small systems.
In addition, the diverse fixed-target data samples collected by the LHCb experiment enable studies of the impact of nuclear geometry on final-state particle correlations. By comparing collision systems involving targets with different nuclear structures, flow measurements can probe the connection between nuclear shape, initial-state anisotropy, and the subsequent hydrodynamic evolution of the produced medium. In particular, recent measurements in PbNe collisions provide experimental evidence for the distinctive bowling-pin geometry of ground state $^{20}$Ne nucleus, demonstrating the sensitivity of collective flow to nuclear structure in high-energy collisions.
