Classification of initial state granularity via 2d Fourier Expansion

Understand

A new method to quantify fluctuations in the initial state of heavy ion collisions is presented.

• The initial state energy distribution is decomposed with a set of orthogonal basis functions which include both angular and radial variation.
• The resulting two dimensional Fourier coefficients provide additional information about the nature of the initial state fluctuations compared to a purely angular decomposition.
• We apply this method to ensembles of initial states generated by both Glauber and Color Glass Condensate Monte-Carlo codes.