Initial correlations of the Glasma energy-momentum tensor

Understand

We present an analytical calculation of the covariance of the energy-momentum tensor associated to the gluon field produced in ultra-relativistic heavy ion collisions at early times, the Glasma.

• This object involves the two-point and single-point correlators of the energy-momentum tensor ($\langle T^{\mu\nu}(x_{\perp})T^{\sigma\rho}(y_{\perp})\rangle$ and $\langle T^{\mu\nu}(x_{\perp})\rangle$, respectively) at proper time $\tau\!=\!0^+$.
• Our approach is based on the Color Glass Condensate effective theory, which allows us to map the fluctuations of the valence color sources in the colliding nuclei to those of the energy-momentum tensor of the produced gluon fields via the solution of the classical equations of motion in the presence of external currents.
• The color sources in the two colliding nuclei are characterized by Gaussian correlations, albeit in more generality than in the McLerran-Venugopalan model, allowing for non-trivial impact parameter and transverse dependence of the two-point correlator.