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arXiv · 2512.24024

Inflationary QCD phase diagram

Kohei Fujikura·Toshifumi Noumi
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Abstract

Motivated by the cosmological collider program, which aims to probe high-energy physics through inflation, we investigate the phase diagram of multi-flavor QCD in de Sitter spacetime with a flavor-universal axial chemical potential induced by a rolling inflaton coupled to fermions. We determine the first-order critical line and a critical point as functions of the Hubble parameter and the axial chemical potential, employing an effective description of chiral symmetry breaking within the framework of the Nambu--Jona-Lasinio model. We find that a first-order chiral phase transition may occur during inflation or at its end when the axial chemical potential is sufficiently large and crosses the critical line. This provides a cosmological collider analogue of the QCD phase diagram explored in heavy-ion colliders.

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Kohei Fujikura, Toshifumi Noumi. 2025-12-30. Inflationary QCD phase diagram. https://arxiv.org/abs/2512.24024

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