Universal Fluctuation-Driven Eccentricities in Proton-Proton, Proton-Nucleus, and Nucleus-Nucleus Collisions

• DOI: 10.1103/physrevlett.112.082301
• Publication Date: 2014-02-25T19:58:41Z
• Authors: Li Yan; Jean-Yves Ollitrault
• Keywords: Parametrization (atmospheric modeling); Elliptic flow

We show that the statistics of fluctuation-driven initial-state anisotropies in proton-proton, proton nucleus and nucleus-nucleus collisions is to a large extent universal. propose simple parametrization for probability distribution Fourier coefficient ${ϵ}_{n}$ harmonic $n$, which good agreement with Monte Carlo simulations. Our results provide explanation 4-particle cumulant triangular flow measured Pb-Pb elliptic recently $p\text{\ensuremath{-}}\mathrm{Pb}$ collisions. Both arise as natural consequences condition initial are bounded by unity. argue rms anisotropy $n$ can be directly extracted from ratio ${v}_{n}{4}/{v}_{n}{2}$: this gives direct access property density profile experimental data. also make quantitative predictions small lifting degeneracy between ${v}_{n}{4}$, ${v}_{n}{6}$, ${v}_{n}{8}$. If confirmed future experiments, they will support picture long-range correlations observed at LHC originate collective proportional anisotropy.