Year: 2024
Type: article
Abstract: Fluctuations of conserved charges calculated on the lattice which can be measured experimentally, are well reproduced by a hadron resonanse gas model at temperatures below $$T_{ch} \sim 155$$ T ch ∼ 155 MeV and radically deviate from the hadron resonance gas predictions above the chiral restoration crossover. This behaviour is typically interpreted as an indication of deconfinement in the quark-gluon plasma regime. We present an argument that this interpretation may be too simple. The argument is based on the scaling of quantities with the number of colors: demonstration of deconfinement and QGP requires observable that is sensitive to $$\sim N_c^2$$ ∼ N c 2 gluons while the conserved charges are sensitive only to quarks and above $$T_{ch}$$ T ch scale as $$N_c^1$$ N c 1 . The latter scaling is consistent with the existence of an intermediate regime characterized by restored chiral symmetry and by approximate chiral spin symmetry which is a symmetry of confining interaction. In this regime the energy density, pressure and entropy density scale as $$N_c^1$$ N c 1 . In the large $$N_c$$ N c limit this regime might become a distinct phase separated from the hadron gas and from QGP by phase transitions. A natural observable that associates with deconfinement and is directly sensitive to deconfined $$N_c^2-1$$ N c 2 - 1 gluons is the Polyakov loop; in the $$N_c=3$$ N c = 3 world it remains very close to 0 at temperatures well above chiral crossover, reaches the value $$\sim 0.5$$ ∼ 0.5 around $$\sim 3T_{ch}$$ ∼ 3 T ch and the value close to 1 at temperatures $$\sim 1$$ ∼ 1 GeV.
Source: The European Physical Journal A
Authors: T. D. Cohen, L. Ya. Glozman
Institutions: University of Maryland, College Park, University of Graz
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,790
OpenAlex ID: W4402079595