Columbia plot based on symmetry-improved CJT formalism in linear sigma model

Fuente: arXiv
Saved in:
Bibliographic Details
Main Authors: Guan, Yuepeng, Kawaguchi, Mamiya, Matsuzaki, Shinya, Tomiya, Akio
Format: Preprint
Published: 2025
Subjects:
Online Access:
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866908764470247424
author Guan, Yuepeng
Kawaguchi, Mamiya
Matsuzaki, Shinya
Tomiya, Akio
author_facet Guan, Yuepeng
Kawaguchi, Mamiya
Matsuzaki, Shinya
Tomiya, Akio
contents We study the Columbia plot for the chiral phase transition in the framework of a three-flavor linear sigma model based on the Cornwall-Jackiw-Tomboulis (CJT) formalism. The conventional CJT approach with the Hartree truncation suffers from artificial chiral breaking, leading to the violation of the Nambu-Goldstone theorem and the (anomalous) chiral Ward-Takahashi identities. We apply the symmetry-improved CJT formalism to resolve this issue. We observe a first-order phase transition and a tricritical point in the light-quark mass regime, which is fairly insensitive to the size of the sigma meson, in contrast to the conventional CJT approach. The tricritical point, found on the $m_s$ axis, is at $m_s^{\rm tri}/m_s^{\rm phys.} = 0.175$ with $m_s^{\rm phys.}$ being the physical strange quark mass in real-life QCD. The critical pion mass in the three-flavor symmetric limit, on the second-order boundary, is measured at $m_π\sim 52.4$ MeV, with the critical temperature $T_c \sim 51.7$ MeV.
format Preprint
id arxiv_https___arxiv_org_abs_2508_02257
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Columbia plot based on symmetry-improved CJT formalism in linear sigma model
Guan, Yuepeng
Kawaguchi, Mamiya
Matsuzaki, Shinya
Tomiya, Akio
High Energy Physics - Phenomenology
We study the Columbia plot for the chiral phase transition in the framework of a three-flavor linear sigma model based on the Cornwall-Jackiw-Tomboulis (CJT) formalism. The conventional CJT approach with the Hartree truncation suffers from artificial chiral breaking, leading to the violation of the Nambu-Goldstone theorem and the (anomalous) chiral Ward-Takahashi identities. We apply the symmetry-improved CJT formalism to resolve this issue. We observe a first-order phase transition and a tricritical point in the light-quark mass regime, which is fairly insensitive to the size of the sigma meson, in contrast to the conventional CJT approach. The tricritical point, found on the $m_s$ axis, is at $m_s^{\rm tri}/m_s^{\rm phys.} = 0.175$ with $m_s^{\rm phys.}$ being the physical strange quark mass in real-life QCD. The critical pion mass in the three-flavor symmetric limit, on the second-order boundary, is measured at $m_π\sim 52.4$ MeV, with the critical temperature $T_c \sim 51.7$ MeV.
title Columbia plot based on symmetry-improved CJT formalism in linear sigma model
topic High Energy Physics - Phenomenology
url https://arxiv.org/abs/2508.02257