| Autor: |
Rai, Suraj Kumar, Tiwari, Vivek Kumar |
| Zdroj: |
European Physical Journal Plus; Oct2020, Vol. 135 Issue 10, p1-1, 1p |
| Abstrakt: |
We report on the U A (1) symmetry restoration resulting due to temperature dependence of the coefficient c(T) for the Kobayashi–Maskawa–’t Hooft determinant (KMT) term in a modified 2 + 1 flavor Polyakov loop quark–meson model having fermionic vacuum correction term. Temperature dependence of KMT coupling c(T) drives the nonstrange condensate melting to significantly smaller temperatures in comparison with the constant c case. Further due to c(T), m η ′ decreases from its vacuum value by 220 MeV near T = 176 MeV after the chiral transition ( T c χ = 154.9 MeV). This is similar to the η ′ in-medium mass drop of at least 200 MeV as reported by Csorgo and Vertesi in Ref (Phys Rev Lett 105:182301, 2010; Phys Rev C 83:054903 2011), as an experimental signature of the effective restoration of U A (1) symmetry. The pseudoscalar mixing angle θ p achieves anti-ideal mixing in the influence of c(T). The η meson becomes light quark system ( η NS ) at T = 176 MeV and changes its identity with η ′ meson which becomes strange quark system ( η S ). The degenerated temperature variations of σ , π meson masses merges with the temperature variations of the masses of degenerated a 0 , η mesons near 275 MeV. It means that for c(T) when m σ = 400 MeV, the U A (1) restoration takes place at 1.75 T c χ = 275 MeV. [ABSTRACT FROM AUTHOR] |
| Databáze: |
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