Study of the scalar and pseudoscalar meson mass spectrum above the QCD chiral phase transition, using an effective Lagrangian approach

Giulio Cianti; Enrico Meggiolaro

doi:10.1140/epja/s10050-026-01867-8

paper

Study of the scalar and pseudoscalar meson mass spectrum above the QCD chiral phase transition, using an effective Lagrangian approach

arXiv:2510.19549 · doi:10.1140/epja/s10050-026-01867-8

Abstract

In this work, expanding on previous analyses, we employ an effective Lagrangian approach to investigate the mass spectrum of scalar and pseudoscalar mesons at finite temperature, above the (pseudo-)critical temperature $T_{c}$ , in a "realistic" $N_{f} = 2 + 1$ flavor scenario with degenerate $u p$ and $d o w n$ quarks and a heavier $s t r an g e$ quark: $0 < m_{u} = m_{d} ≪ m_{s}$ . The model's predictions are then critically compared with available lattice QCD results (where meson screening masses are extracted from chiral susceptibilities, which correspond to two-point correlation functions of suitable interpolating operators), looking, in particular, for signatures of the breaking of the $U (1)$ axial symmetry above $T_{c}$ .

36 pages, 8 figures; revised version, published in Eur. Phys. J. A: a misprint in Eq. (3.25) has been corrected and new comments and a relevant reference have been added