Refractive Distortions of Two-Particle Correlations from Classical Trajectory Calculations

Calculations of two-particle correlations usually assume particles interact only pair-wise after their final collisions with third bodies. By considering classical trajectories, we show that interactions with the mean field can alter the spatial dimensions of the outgoing phase-space-density profiles by tens of percent, consistent with more complicated quantum complications.Comment: 10 pages, 5 figure

General Charge Balance Functions, A Tool for Studying the Chemical Evolution of the Quark-Gluon Plasma

In the canonical picture of the evolution of the quark-gluon plasma during a high-energy heavy-ion collision, quarks are produced in two waves. The first is during the first fm/c of the collision, when gluons thermalize into the QGP. After a roughly isentropic expansion that roughly conserves the number of quarks, a second wave ensues at hadronization, 5-10 fm/c into the collision. Since each hadron contains at least two quarks, the majority of quark production occurs at this later time. For each quark produced in a heavy-ion collision, an anti-quark of the same flavor is created at the same point in space-time. Charge balance functions identify, on a statistical basis, the location of balancing charges for a given hadron, and given the picture above one expects the distribution in relative rapidity of balancing charges to be characterized by two scales. After first demonstrating how charge balance functions can be created using any pair of hadronic states, it will be shown how one can identify and study both processes of quark production. By considering balance functions of several hadronic species, and by performing illustrative calculations, this class of measurement appears to hold the prospect of providing the field's most stringent insight into the chemical evolution of the QGP.Comment: 11 pages, 1 figure (explanations and steps added to derivations, typos fixed, minor error in calculation fixed and some signs fixed

Shapes and Sizes from Non-Identical-Particle Correlations

I review the prospects for measuring source characteristics from correlations other than those involving identical pions. Correlations generated from Coulomb and strong interactions are shown to provide remarkable resolving power for determining three-dimensional information, in some cases accessing more detail than can be represented by Gaussian fits

Identifying the Charge Carriers of the Quark-Gluon Plasma

Charge correlations in lattice gauge calculations suggest that up, down and strange charges move independently in the QGP (quark-gluon plasma), and that the density of such charges is similar to what is expected from simple thermal arguments. Here, we show how specific elements of the charge-charge correlation matrix in the QGP survive hadronization and become manifest in final-state charge-charge correlation measurements.Comment: 4 pages, 4 figure

Viewing the Chemical Evolution of the Quark-Gluon Plasma with Charge Balance Functions

Correlations from charge conservation are affected by when charge/anticharge pairs are created during the course of a relativistic heavy ion collision. For charges created early, balancing charges are typically separated by the order of one unit of spatial rapidity by the end of the collision, whereas those charges produced later in the collision are far more correlated. By analyzing correlations from STAR for different species, I show that one can distinguish the two separate waves of charge creation expected in a high-energy collision, one at early times when the QGP is formed and a second at hadronization. Further, I extract the density of up, down and strange quarks at in the QGP and find agreement at the 20% level with expectations for a chemically thermalized plasma.Comment: Proceedings of "Critical Point and the Onset of Deconfinement, Napa, CA, March 2013, 9 pages, 3 figure

Refractive Distortions of Two-Particle Correlations

Using optical model calculations it has recently been shown that refractive phenomena from the collective mean field can significantly alter the sizes inferred from two-pion correlations. We demonstrate that such effects can be accounted for in classical calculations if mean field effects are included.Comment: Proceedings for International Symposium on Multiparticle Dyanamics, Kromeriz, Czech Republic, Aug. 200

Extending the Reach of Hydrodynamics

Recent and ongoing improvements to hydrodynamic treatments at RHIC are extending the physics reach of hydrodynamics, and improving the phenomenology. Here, the links between technological improvements and the extension of physics are emphasized.Comment: Proceedings for Zimanyi '75 Workshop, Budapest, 200