Seminar in Hadronic Physics

Quantifying the initial state granularity and triangular flow in relativistic heavy ion collisions

Hannah Petersen

Duke University

In this talk I will present a systematic study of the granularity of the initial state of hot and dense QCD matter produced in ultra-relativistic heavy-ion collisions and its influence on bulk observables like particle yields, m_T spectra and elliptic flow. For our investigation we use a hybrid transport model, based on (3+1)d hydrodynamics and a microscopic Boltzmann transport approach. The initial conditions are generated by a non-equilibrium hadronic transport approach and the size of their fluctuations can be adjusted by defining a Gaussian smoothing parameter σ. As a response to the initial triangularity ε₃ of the collision zone, v₃ is computed in a similar way to the standard event-plane analysis for elliptic flow v₂. It is found that the triangular flow exhibits weak centrality dependence and is roughly equal to elliptic flow in most central collisions. We also explore the transverse momentum and rapidity dependence of v₂ and v₃ for charged particles as well as identified particles and point out the potential of triangular flow to further quantify the initial granularity.