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arXiv · 2605.07126

The sigma meson ($f_0$) at finite temperature with truncated overlap fermions

S. Date·Y. Murakami·M. Sekiguchi·H. Wada·M. Wakayama
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Abstract

We study the temperature dependence of meson screening masses in two-flavour lattice QCD using dynamical truncated overlap fermions (TOF), a type of lattice chiral fermions. The screening masses for the $\pi$, $\rho$, $a_1$, $a_0$, and the sigma $(f_0)$ mesons are extracted by computing spatial correlation functions. Above the pseudocritical temperature $T_{\rm pc}$, the $\pi$ and $f_0$ screening masses become degenerate, consistent with chiral restoration. The $(\pi,f_0)$ and $(\rho,a_1)$ pairs also show the expected degeneracy. Decomposition of the $f_0$ propagator reveals that the connected contribution dominates above $T_{\rm pc}$, while the disconnected part becomes significant below $T_{\rm pc}$, explaining the reduced statistical clarity observed at low $T$. These results demonstrate that dynamical TOF simulations can capture the qualitative thermal behaviour of the scalar sector.

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S. Date, Y. Murakami, M. Sekiguchi, H. Wada, M. Wakayama. 2026-05-08. The sigma meson ($f_0$) at finite temperature with truncated overlap fermions. https://arxiv.org/abs/2605.07126

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