Toward initial conditions of conserved charges. Part I. Spatial correlations of quarks and antiquarks

Abstract

In this paper, we study the spatial correlations among quarks and antiquarks produced at midrapidity by gluon pair production in the color glass condensate framework. This paper is the first part of a series in which we calculate a complete set of quark/quark, quark/antiquark, and antiquark/antiquark spatial correlation functions in heavy-light ion collisions, with the goal of incorporating their conserved charges into the initial conditions of hydrodynamics. The physical mechanisms captured in this calculation include geometric, entanglement, and interaction-mediated correlations. In this first paper, we construct the building blocks for the correlations arising from single-and double-pair production, studying in detail the single-pair case and the general features of the double-pair case. We find a rich correlation structure in transverse coordinate space, with different mechanisms dominating over different length scales, and we present explicit results for the quark-antiquark correlations in the single-pair production regime. We reserve a detailed discussion of the double-pair production regime for the next paper in this sequence.

Particle correlations from the initial state

“…9 A comprehensive study of gluon-gluon, quark-quark and quarkantiquark correlations in pA collisions is also performed in [75,76].…”

Effect of non-eikonal corrections on azimuthal asymmetries in the color glass condensate

“…For the collision of dilute objects like proton-proton, the "Glasma graph" approximation [27,28], that encodes both Bose enhancement and Hanbury-Brown-Twiss (HBT) effects [29,30,31,32], has been developed and used to describe experimental data [33,34,35,36]. Besides two gluon correlations, those among three and four [37,38] have also been studied, and also those between two quarks [39,40]. The extension to dilute-dense (proton-nucleus) collisions was later done numerically [41] and analytically [42,43,44], including three gluon correlations [43], and applied to describe data [45,46].…”

Initializing BSQ with Open-Source ICCING

“…An expression for the differential probability distribution dP dr ⊥ dα for a gluon to split into a q q pair with given kinematics is the result of the calculation in Ref. [43]. Here r is the separation vector between the quark and antiquark, and α is the fraction of light-front momentum (i.e., energy) carried by the quark.…”

“…To illustrate the algorithm and its physical consequences, the Trento initial condition generator [40][41][42], is chosen for its ability to match experimental results and its model agnostic construction, and the g → q q spatial correlation functions derived in Ref. [43] are used. Charge Density (fm -3 ) FIGURE 1.…”