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arXiv · 2601.21232

Chemical potential differentials in the QCD phase diagram from heavy-ion isobar collisions

Joaquin Grefa·Chun Yue Tsang·Rajesh Kumar·Veronica Dexheimer·Claudia Ratti·Zhangbu Xu
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Abstract

Temperature and baryon, charge, and strangeness chemical potentials characterize QCD matter under extreme conditions. Differences between these chemical potentials and their ratios probe conserved-charge correlations and the system's response in the multidimensional QCD phase diagram. We extract these quantities from STAR Ru+Ru and Zr+Zr isobar collisions using a Bayesian thermal analysis of hadron yields, which substantially reduces systematic uncertainties, and compare them with Taylor-expanded lattice-QCD and Chiral Mean Field model predictions. Isobar collisions thus emerge as a precision probe of four-dimensional QCD thermodynamics.

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Joaquin Grefa, Chun Yue Tsang, Rajesh Kumar, Veronica Dexheimer, Claudia Ratti, Zhangbu Xu. 2026-01-29. Chemical potential differentials in the QCD phase diagram from heavy-ion isobar collisions. https://arxiv.org/abs/2601.21232

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