Evolving charge correlations in a hybrid model with both hydrodynamics and hadronic Boltzmann descriptions

Abstract

Correlations related to local charge conservation provide insight into the creation and evolution of up, down and strange charges in the quark-gluon plasma. Here, the evolution of charge correlations is overlaid onto a hydrodynamic calculation for the regions where temperature exceed 155 MeV, then transferred and carried through a microscopic model of the hadronic stage. Thus, for the first time, charge correlations are evolved consistently with a full state-of-the-art description of a heavy-ion collision. The charge correlations are projected onto charge balance functions, which characterize such correlations in the final state, and are presented as a function of relative rapidity and relative azimuthal angle for Au/Au collisions. The role of the hadronic stage is investigated. Calculation of the contribution to charge-separation observables related to the chiral magnetic effect are also presented. Calculations are compared to data from the STAR Collaboration at RHIC (Relativistic Heavy Ion Collider) data when possible.arXiv:1812.05649v1 [nucl-th]

Charge Balance Functions for Heavy-Ion Collisions at LHC Energies

“…Experimentally, measurements at RHIC have quantitatively confirmed the resulting model-based expectations that B π|π (∆y) narrows with centrality while B K|K and B p|p do not, and that for central collisions charge balance functions for kaons and protons are broader than those for pions [7,21,23]. By assuming that the matter was chemically equilibrated at an early time, and that the diffusivity matched that of lattice calculations, the model was able to explain the width in relative rapidity of all the balance functions measured by STAR [22].…”

“…At the hyper-surface separating these two descriptions, the charge-charge correlation function must be translated into correlations indexed by hadron species based on statistical arguments. The accurate modeling of conserved charge dynamics thus raises a number technical challenges for constructing and propagating charge correlations throughout the collision lifetime which have been addressed previously in the context of heavy-ion collisions at RHIC [20][21][22].…”

The Interplay of Femtoscopic and Charge-Balance Correlations

“…At lower energies, the NA49 Collaboration has also measured BFs at CERN SPS energies [27,28]. Detailed theoretical models describing the dynamics of charge correlations, superimposed onto state-of-theart dynamical descriptions of the bulk evolution, have been able to quantitatively reproduce several features of measurements at both RHIC and the LHC [4,[29][30][31]. The inferred diffusivity and chemistry from comparing models to data appears consistent with expectations from lattice gauge theory [32][33][34].…”

“…Much more realistic models of BFs have been construced and analyzed, e.g. [4,30,31]. These more sophisticated treatments account for the difference between the distance scales over which strangeness, electric charge or baryon number are conserved.…”

Dynamic modeling for heavy-ion collisions

“…Strange quarks produced in relativistic nuclear collisions are an interesting probe for studying the evolution of the collisions. Since the collision system is strangeness neutral, the s s pair production mechanism is sensitive to the properties of strongly-interacting matter, especially at the early time [17]. The partonic and hadronic production channels are very different and may signal the onset of deconfinement and the quark-gluon plasma [18].…”