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arXiv · 2507.19289

Determination of the $\phi$-meson production process and its absorption cross section via directed flow

Jan Steinheimer·Tom Reichert·Marcus Bleicher
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Abstract

We show that the directed flow of $\phi$-mesons in Au+Au collisions at $\sqrt{s_{NN}}=3$ GeV, is sensitive on production and the absorption cross section of the $\phi$ in a nuclear medium. This provides a new observable to constrain the in-medium properties of the $\phi$ which is independent of its absolute production rate. It is shown that the STAR data disfavor any significant $\phi$-N absorption in dense nuclear matter and are consistent with a very small cross section of the $\phi$ comparable to the vacuum cross section. The similarity of the $\phi$-meson and proton directed flow also indicates that the $\phi$ is produced in conjunction with a baryon.

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Jan Steinheimer, Tom Reichert, Marcus Bleicher. 2025-07-25. Determination of the $\phi$-meson production process and its absorption cross section via directed flow. https://doi.org/10.1016/j.physletb.2025.139870

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