Quark--Hadron Duality at Finite Temperature

Abstract

At low temperatures we expect that all QCD observables are defined in terms of hadrons. This includes the partition function as well as the Polyakov loop in all representations. We analyze the physics underlying a microscopic derivation of the hadron resonance gas.

Determination ofU(1)Arestoration from pion anda0Ito1, Yonemura2, Takahashi3 et al. 2016Phys. Rev. D201250View full textAdd to dashboardCite

“…In LQCD the definition is Φ LQCD = tr c P exp[i 1/T 0 dτ A 4 (τ, x)] /3, while in the PNJL model based on the Polyakov gauge and the mean field approximation the definition is Φ PNJL = tr c exp[i A 4 /T ]/3, although both are order parameters of Z 3 symmetry [56,57]; see for example Ref. [31,58] as a trial to solve this problem.…”

Quark Properties from the Hadron Resonance Gas

“…Much of our understanding of the QCD dynamics at finite temperature is linked to the Helmholtz free energy defined as the maximum work the system can exchange at fixed temperature between two heavyQQ at separation r. In the confined phase, the correlator between Polyakov loops becomes [3] …”

“…In this contribution we analyze to what extent can one describe the QCD thermodynamics from the hadronic spectrum. We thus hope to identify the nature of non-hadronic precursors of the crossover to the quark-gluon plasma in terms of low temperature partonic expansions [1,2] (see [3] for a review). The relation between spectrum and partition function provides the thermodynamic free energy F Z(T ) = n e −En/T ≡ e −F/T .…”

Does $X(3872)$ count?

“…The recent discovery of the so-called X,Y,Z states arises the question if these states must be included in the PDG and whether or not they add redundancy when building the hadron spectrum [4,6]. In this work we study this effect for the X(3872) resonance, a 1 ++ state discovered in 2003 by the Belle Collaboration [7], whose properties point to a dominant DD * -molecular structure.…”

“…Also, if we build the cumulative number of all the states listed in the Particle Data Group (PDG), N PDG (M), we can check that it fits the trace anomaly, ε − 3P = T 5 ∂ T (log Z/T 3 )/V , on the lattice at temperatures T 200MeV below the crossover to the Quark-Gluon Plasma (QGP) phase [3] (see also Ref. [4] and references therein).…”