Rapidity decorrelation from hydrodynamic fluctuations and initial fluctuations

The rapidity decorrelation is interesting phenomena in understanding the longitudinal dynamics of the quark gluon plasma (QGP) produced in the intermediate stage of high-energy nuclear collisions. We analyze the rapidity decorrelation to understand the longitudinal dynamics of the QGP. We employ an integrated dynamical model with hydrodynamic fluctuations and initial longitudinal fluctuations to perform event-by-event numerical simulations of Pb+Pb collisions at the LHC energy. Including both fluctuations, we reproduce centrality dependence of rapidity decorrelation measured by CMS collaboration. We conclude hydrodynamic fluctuations and initial longitudinal fluctuations are both important to understand the centrality dependence of rapidity decorrelation. (author)