The Polyakov loop and the hadron resonance gas model
arXiv:1204.2424 · doi:10.1103/PhysRevLett.109.151601
Abstract
The Polyakov loop has been used repeatedly as an order parameter in the deconfinement phase transition in QCD. We argue that, in the confined phase, its expectation value can be represented in terms of hadronic states, similarly to the hadron resonance gas model for the pressure. Specifically, L(T) \approx 1/2\sum_αg_α\,e^(-Δ_α/T), where g_αare the degeneracies and Δ_αare the masses of hadrons with exactly one heavy quark (the mass of the heavy quark itself being subtracted). We show that this approximate sum rule gives a fair description of available lattice data with N_f=2+1 for temperatures in the range 150MeV<T<190MeV with conventional meson and baryon states from two different models. For temperatures below 150MeV different lattice results disagree. One set of data can be described if exotic hadrons are present in the QCD spectrum while other sets do not require such states.
5 pages, 4 figures. Error in normalization corrected. Excited states included. Substantially revised
References in corpus (7)
- The order of the quantum chromodynamics transition predicted by the standard model of particle physics
- The QCD equation of state with dynamical quarks
- Equation of state and QCD transition at finite temperature
- The Phase Structure of the Polyakov--Quark-Meson Model
- Renormalized Polyakov loops in many representations
- The Polyakov Loop and its Relation to Static Quark Potentials and Free Energies
- Trace Anomaly, Thermal Power Corrections and Dimension Two condensates in the deconfined phase