Meson mass spectrum in isospin QCD medium from the Nf=2+1 quark-meson model
Abstract
We study phase structures, meson mass spectra, and sound velocities at finite temperature and density in QCD with isospin chemical potential (μI). We employ the quark-meson model with Nf=2+1, incorporating the Kobayashi-Maskawa-'t Hooft type coupling to capture dynamical effects of the U(1)A axial anomaly. Within the mean-field approximation at quark one-loop, we analyze the onset of pion condensation, which manifests as a second-order phase transition at low temperatures and may exhibit a first-order behavior at higher temperatures within this approximation. We examine the corresponding mass spectra of scalar and pseudoscalar singlet-octet mesons, in which the π+ mass is exactly massless in the superfluid phase due to its Nambu-Goldstone boson nature. The neutral pion mass is, meanwhile, found to exhibit a strictly linear growth with μI in the pion condensed phase. We also investigate the isothermal squared sound velocity and identify characteristic structures associated with the phase transitions. Furthermore, we highlight how enhanced U(1)A anomaly effects facilitate the pion condensate to generate a less-pronounced sound velocity peak in cold medium. Our findings are expected to provide future lattice simulations with useful information on meson mass spectra from symmetry aspects.
Related
- Diquark Correlators and Phase Structure in the Quark-Meson-Diquark Model beyond Mean Field
- In-Medium Modification of ϕ Meson Mass over Temperature and Momentum
- Valence-quark-core and meson-cloud effects on electromagnetic form factors of Δ baryons
- Skyrme-quark-meson-coupling energy density functional predictions to nuclear ground state properties
- Diffractive Vector-Meson Production from the Light-Front Quark Model
BibTeX
@misc{gao2026meson,
title = {{Meson mass spectrum in isospin QCD medium from the $N_f=2+1$ quark-meson model}},
author = {Yu-Han Gao and Xu-Guang Huang and Daiki Suenaga},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.03385},
eprint = {2609.03385},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.03385},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Meson mass spectrum in isospin QCD medium from the N_f=2+1 quark-meson model
AU - Yu-Han Gao
AU - Xu-Guang Huang
AU - Daiki Suenaga
PY - 2026
DA - 2026/09/03
PB - arXiv
DO - 10.48550/arxiv.2609.03385
UR - https://arxiv.org/abs/2609.03385
AB - We study phase structures, meson mass spectra, and sound velocities at finite temperature and density in QCD with isospin chemical potential (μ_I). We employ the quark-meson model with N_f=2+1, incorporating the Kobayashi-Maskawa-'t Hooft type coupling to capture dynamical effects of the U(1)_A axial anomaly. Within the mean-field approximation at quark one-loop, we analyze the onset of pion condensation, which manifests as a second-order phase transition at low temperatures and may exhibit a first-order behavior at higher temperatures within this approximation. We examine the corresponding mass spectra of scalar and pseudoscalar singlet-octet mesons, in which the π_+ mass is exactly massless in the superfluid phase due to its Nambu-Goldstone boson nature. The neutral pion mass is, meanwhile, found to exhibit a strictly linear growth with μ_I in the pion condensed phase. We also investigate the isothermal squared sound velocity and identify characteristic structures associated with the phase transitions. Furthermore, we highlight how enhanced U(1)_A anomaly effects facilitate the pion condensate to generate a less-pronounced sound velocity peak in cold medium. Our findings are expected to provide future lattice simulations with useful information on meson mass spectra from symmetry aspects.
ER -