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arXiv · 2601.03710

Chiral anomaly: from vacuum to Columbia plot

Francesco Giacosa·Győző Kovács·Péter Kovács·Robert D. Pisarski·Fabian Rennecke
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Abstract

We use a low-energy effective approach, the extended linear sigma model, to study realizations of the $U(1)_A$ anomaly with different operators, linear and quadratic in the 't Hooft determinant. After discussing the parameterization in agreement with vacuum's phenomenology, we investigate the influence of these different anomaly terms on the Columbia plot: the square of the 't Hooft determinant favors a cross-over for small quark masses. Finally, we also discuss the extension of the 't Hooft determinant to cases in which different mesonic multiplets interact with each other. Novel chiral anomalous interaction terms involving excited (pseudo)scalar states, pseudovector, and pseudotensor mesons are expressed via a mathematical extension of the determinant, denoted as a polydeterminant.

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Francesco Giacosa, Győző Kovács, Péter Kovács, Robert D. Pisarski, Fabian Rennecke. 2026-01-07. Chiral anomaly: from vacuum to Columbia plot. https://arxiv.org/abs/2601.03710

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