Topological observables and θ dependence in high temperature QCD from lattice simulations

2025/02/21 by Kotov, A. Yu., Lombardo, M. P., Trunin, A. · 2 citations
#FOS: Physical sciences #High Energy Physics - Lattice (hep-lat) #High Energy Physics - Phenomenology (hep-ph) #High Energy Physics - Theory (hep-th)

paper · doi:10.48550/arxiv.2502.15407

Abstract

We study topology in Quantum Chromodynamics at high temperatures by means of lattice calculations. Simulations are performed with N_f=2+1+1 Wilson twisted mass fermions at maximal twist with physical quark masses, and temperatures T~\gtrsim~180 MeV. The results obtained with three lattice spacings ranging between 0.057 and 0.080 fm are extrapolated to the continuum limit. We compare the results for the topological susceptibility obtained with the field-theoretic definition with those obtained from an observable constructed with the disconnected part of the chiral susceptibility, and we confirm their agreement -- within the largish errors -- on our range of temperatures. We also study the topological charge distribution, the next order cumulant b₂ and, for the first time, the Free Energy as a function of the θ angle. We find a rapid crossover to the Dilute Instanton Gas behaviour above T ≃ 300 MeV for all the observables we have considered.

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• The large-N limit of the topological susceptibility of SU(N) Yang-Mills theories via Parallel Tempering on Boundary Conditions
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