Baryon-Strangeness Correlations: A Diagnostic of Strongly Interacting Matter

Abstract

The correlation between baryon number and strangeness elucidates the nature of strongly interacting matter, such as that formed transiently in high-energy nuclear collisions. This diagnostic can be extracted theoretically from lattice QCD calculations and experimentally from event-by-event fluctuations. The analysis of present lattice results above the critical temperature severely limits the presence of qq bound states, thus supporting a picture of independent (quasi)quarks.

Fluctuations of conserved charges at finite temperature from lattice QCD

“…(2.8) was proposed long ago [11] as a diagnostic for strongly interacting matter. It is supposed to be equal to one for a non-interacting QGP, while it is temperature-dependent and generally smaller than one in a hadronic system.…”

“…[11] as a diagnostic to understand the nature of the degrees of freedom in the QGP, has the following expression in terms of quark number susceptibilities: 3 Details of the lattice simulations…”

“…A quantitative analysis of this observable allows one to draw conclusions about the presence of bound states in the QGP [10]. Another observable which was proposed to this purpose, and which can be obtained from a combination of diagonal and non-diagonal quark number susceptibilities, is the baryon-strangeness correlator [11].…”

K/πFluctuations at Relativistic Energies

“…PACS numbers: 25.75.-q, 24.60.Ky Strangeness enhancement has been predicted to be one of the important signatures of the formation of the quark gluon plasma (QGP) [1,2,3,4,5]. Recently a maximum in the ratio of the yields of K + and π + , K + /π + , has been observed in central Pb+Pb collisions near √ s N N = 7 GeV [6].…”

Meson screening masses in the interacting QCD plasma

“…For what concerns energy densities not too far from the deconfinement transition, the ones presently achievable in the heavy-ion collision experiments, the possible presence of a huge set of neutral and colored bound states surviving up to temperatures of order ∼ 2T c , has been proposed [12,13,14,15] as being able to give a unified interpretation of different experimental evidences: large cross sections, small mean free paths, perfect fluid behavior, fast thermalization, elliptic flow, etc. Actually neither the theoretical description of the QGP thermodynamics in terms of bound states [16,17], nor the interpretation of the experimental data in terms of fast thermalization and perfect fluid behavior [18] is universally accepted.…”