Title: Possible new phase of thermal QCD

Abstract

Using lattice simulations, we show that there is a phase of thermal QCD, where the spectral density ρ(λ) of the Dirac operator changes as 1/λ for infrared eigenvalues λ < T. This behavior persists over the entire low energy band we can resolve accurately, over 3 orders of magnitude on our largest volumes. We propose that in this “IR phase,” the well-known noninteracting scale invariance at very short distances (UV, λ → ∞, asymptotic freedom), coexists with a very different interacting type of scale invariance at long distances (IR, λ < T). Such dynamics may be responsible for the unusual fluidity properties of the medium observed at RHIC and LHC. We point out its connection to the physics of the Banks-Zaks fixed point, leading to the possibility of massless glueballs in the fluid. Our results lead to the classification of thermal QCD phases in terms of IR scale invariance. The ensuing picture naturally subsumes the standard chiral crossover feature at “T_c ” ≈ 155 MeV. Its crucial new aspect is the existence of temperature T_IR (200 MeV < T_IR < 250 MeV) marking the onset of the IR phase and possibly a true phase transition.

Authors:

Alexandru, Andrei; Horváth, Ivan

Publication Date:

2019-11-22

Research Org.:

George Washington Univ., Washington, DC (United States)

Sponsoring Org.:

USDOE Office of Science (SC); National Science Foundation (NSF)

OSTI Identifier:

1575305

Alternate Identifier(s):

OSTI ID: 1800827

Grant/Contract Number:  

FG02-95ER40907; PHY-1151648

Resource Type:

Published Article

Journal Name:

Physical Review D

Additional Journal Information:

Journal Name: Physical Review D Journal Volume: 100 Journal Issue: 9; Journal ID: ISSN 2470-0010

Publisher:

American Physical Society

Country of Publication:

United States

Language:

English

Subject:

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; Astronomy & Astrophysics; Physics