Universality driven analytic structure of the QCD crossover: radius of convergence in the baryon chemical potential

2019/09/30 by Swagato Mukherjee, Vladimir Skokov · 1 citation
Physics and Astronomy · #hep-ph #hep-lat #nucl-th

paper · pdf · doi:10.1103/physrevd.103.l071501

published as Phys. Rev. D 103, 071501 (2021) · 5 pages, 3 figures; published version

arxiv created 2021/04/04 · arxiv updated 2021/04/21

Abstract

Recent lattice QCD calculations strongly indicate that the chiral crossover of QCD at zero baryon chemical potential μ_B is a remnant of the second-order chiral phase transition. Universal properties of this second-order phase transition can be mapped to QCD temperature T and μ_B using non-universal parameters determined by lattice QCD recently. Motivated by these results, first, we discuss the analytic structure of the partition function in the QCD crossover regime - the so-called Yang-Lee edge singularity - solely based on universal properties. Next, utilizing the lattice QCD results for non-universal parameters we map this singularity to the real T and complex μ_B plane, leading to the determination of the radius of convergence is in μ_B in the QCD crossover regime. These universality- and QCD-based results provide tight constraints on the range of validity of the lattice QCD calculations at μ_B. Implication of this result on the location of the conjectured QCD critical point is discussed.

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