Azimuthal anisotropy in U+U collisions at STAR

The azimuthal anisotropy of particle production is commonly used in high-energy nuclear collisions to study the early evolution of the expanding system. The prolate shape of uranium nuclei makes it possible to study how the geometry of the colliding nuclei affects final state anisotropies. It also provides a unique opportunity to understand how entropy is produced in heavy-ion collisions. In this paper, the two- and four-particle cumulant v2v2 (v2{2}v2{2} and v2{4}v2{4}) from U+U collisions at sNN=193 GeV and Au+Au collisions at sNN=200 GeV for inclusive charged hadrons will be presented. The STAR Zero Degree Calorimeters are used to select very central collisions. Differences were observed between the multiplicity dependence of v2{2}v2{2} for most central Au+Au and U+U collisions. The multiplicity dependence of v2{2}v2{2} in central collisions was compared to Monte Carlo Glauber model predictions and it was seen that this model cannot explain the present results.