Initial correlations of the Glasma energy-momentum tensor
MetadataShow full item record
Heavy Ion Phenomenology
Albacete, J. L., Guerrero-Rodríguez, P., & Marquet, C. (2019). Initial correlations of the Glasma energy-momentum tensor. Journal of High Energy Physics, 2019(1), 73.
SponsorshipWe thank Tuomas Lappi and Jean-Yves Ollitrault for illuminating discussions on various aspects of this project. The work of JLA and PGR is partially funded by a FP7- PEOPLE-2013-CIG Grant of the European Commission, reference QCDense/631558, and by the MINECO project FPA2016-78220 of the Spanish Government. The work of CM was supported in part by the Agence Nationale de la Recherche under the project ANR- 16-CE31-0019-02. PGR also acknowledges nancial support from the `La Caixa' Banking Foundation.
We present an analytical calculation of the covariance of the energy-momentum tensor associated to the gluon eld 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 (〈Tμν (x⊥)Tσρ(y⊥)〉 and 〈Tμν (x⊥)〉, respectively)) at proper time T = 0+. Our approach is based on the Color Glass Condensate effective theory, which allows us to map the uctuations of the valence color sources in the colliding nuclei to those of the energy-momentum tensor of the produced gluon elds 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. We compare our results to those obtained under the Glasma Graph approximation, nding agreement in the limit of short transverse separations. However, important differences arise at larger transverse separations, where our result displays a slower fall-off than the Glasma Graph result (1=r2 vs. 1=r4 power-law decay), indicating that the color screening of the correlations in the transverse plane occurs at distances larger than 1=Qs by a logarithmic factor sensitive to the infrared. In the Glasma ux tube picture, this implies that the color domains are larger than originally estimated.