  We study the fluctuations of the anisotropy of the energy density profile
created in a high-energy collision at the LHC. We show that the anisotropy in
harmonic $n$ has generic non-Gaussian fluctuations. We argue that these
non-Gaussianities have a universal character for small systems such as p+Pb
collisions, but not for large systems such as Pb+Pb collisions where they
depend on the underlying non-Gaussian statistics of the initial density
profile. We generalize expressions for the eccentricity cumulants
$\varepsilon_2\{4\}$ and $\varepsilon_3\{4\}$ previously obtained within the
independent-source model to a general fluctuating initial density profile.

Nuclear Theory;High Energy Physics - Phenomenology;Nuclear Experiment