Impact of nuclear structure on longitudinal flow decorrelations in high-energy isobar collisions

Fluctuations of harmonic flow along pseudorapidity, known as flow decorrelations, are an important probe of the initial state geometry of the quark-gluon plasma. The flow decorrelations are shown to be sensitive to the collective structure of the colliding nuclei, as revealed clearly by comparing collisions of isobars, ${}^{96}$Ru+${}^{96}$Ru and ${}^{96}$Zr+${}^{96}$Zr, which have different nuclear structures. The flow decorrelations in central collisions are mostly sensitive to nuclear deformations, while those in the mid-central collisions are primarily sensitive to differences in skin thickness between ${}^{96}$Ru and ${}^{96}$Zr. Longitudinal flow decorrelations in heavy-ion collisions are a new tool to probe the structure of colliding nuclei.