https://doi.org/10.1140/epja/s10050-024-01387-3
Regular Article - Theoretical Physics
On interpretation of fluctuations of conserved charges at high T
1
Department of Physics and Maryland Center for Fundamental Physics, University of Maryland, 20742, College Park, MD, USA
2
Institute of Physics, University of Graz, 8010, Graz, Austria
Received:
12
April
2024
Accepted:
26
July
2024
Published online:
31
August
2024
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 
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 
gluons while the conserved charges are sensitive only to quarks and above 
scale as 
. 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 . In the large 
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 
gluons is the Polyakov loop; in the 
world it remains very close to 0 at temperatures well above chiral crossover, reaches the value 
around 
and the value close to 1 at temperatures 
GeV.
© The Author(s) 2024
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