Early-time dynamics of hadronic collisions beyond the Gaussian approximation of the Color Glass Condensate

Abstract

We plan to study the early time dynamics of hadronic collisions at the LHC energies using the Color Glass Condedensate (CGC) formalism coupled with the classical Yang-Mills (CYM) equations. The CGC+CYM framework is the starting point of any CGC based calculation, where observables are obtained as an average over a given weight functional representing the color charge distribution inside the colliding hadrons. While most CGC calculations assume the McLerran-Venugopalan (MV) model of Gaussian color charge distribution, we intend to calculate observables employing a non-Gaussian weight function, which includes the already known higher order corrections to the MV model. While the MV model is well justified for heavy-ion collisions, these non-Gaussian corrections are expected to be important on smaller collision systems, as proton-nucleus and proton-proton, and may lead to a better understanding of them. We intend to study the effects of these non-Gaussian color charge contributions on the fluctuations of the initial energy density distribution by calculating the covariance of the initial energy-momentum tensor numerically on a lattice. The time evolution of the initial energy density and its fluctuations will also be studied by solving the CYM equations exactly. The inclusion of non-Gaussian color charge fluctuations in the CGC formalism together with the early time dynamics from the CYM equations can potentially improve the initial conditions for hydrodynamics simulations in small systems. (AU)