Speaker
Description
The anisotropic flow of direct photons is a sensitive probe of the initial geometry in relativistic heavy-ion collisions. Alpha clustering in light nuclei can enhance the initial spatial anisotropies, which can result in larger direct-photon anisotropic flow. In this work, we studied the production and anisotropic flow of direct photons for both central and peripheral collisions of $\alpha$-clustered oxygen nuclei at $\sqrt s_{NN}=7A$ TeV at the LHC, using the GLISSANDO initial-state model together with the MUSIC event-by-event hydrodynamical framework. The tetrahedral $\alpha$-clustered structure of $^{16}O$ produces a significantly larger initial triangular eccentricity compared with collisions involving nuclei with uniform-density distributions. As a result, especially in the most central events, a larger photon triangular-flow coefficient, $v_3(p_T)$, is observed compared with that obtained from collisions with uniform-density distributions. An experimental determination of photon anisotropic flow, together with the ratios of flow coefficients in O+O collisions, is therefore expected to provide valuable insight into the possible clustered structure of light nuclei and to constrain parameters in theoretical modeling.
