English

Energy dependence of rescattering effect on vector mesons spin alignment at RHIC

Nuclear Experiment 2025-07-02 v1 High Energy Physics - Experiment High Energy Physics - Theory Nuclear Theory

Abstract

Spin alignment of vector mesons in heavy-ion collisions provides a novel probe of quark polarization and hadronization mechanism in quark-gluon plasma. Hadronic rescattering may affect the measured spin alignment of vector mesons due to non-uniform rescattering probability in non-central heavy-ion collisions. Using the UrQMD model, we systematically investigated the hadronic rescattering effect on the measurement of ρ00\rho_{00}, the spin alignment parameter, for K0K^{*0}, ϕ\phi, and ρ0\rho^{0} mesons in Au+Au collisions at sNN\sqrt{s_\mathrm{NN}} = 7.7 - 200 GeV. Our results reveal that the measurable ρ001/3\rho_{00} - 1/3 remains unaffected for ϕ\phi, while shows significantly negative (positive) deviations for K0K^{*0} and ρ0\rho^0 with respect to the reaction (production) plane. Quantitatively, the maximum deviation reaches 0.0056-0.0056 (0.02680.0268) for K0K^{*0} and 0.0122-0.0122 (0.04140.0414) for ρ0\rho^{0} with respect to the reaction (production) plane. Notably, the deviations in ρ00\rho_{00} for both K0K^{*0} and ρ0\rho^{0} increase monotonically with increasing collision energy. These findings underscore the critical necessity of accounting for rescattering effects when interpreting spin alignment measurements of short-lived vector mesons in heavy-ion collisions.

Keywords

Cite

@article{arxiv.2507.00706,
  title  = {Energy dependence of rescattering effect on vector mesons spin alignment at RHIC},
  author = {Zihan Liu and Ziyang Li and Wangmei Zha and Zebo Tang},
  journal= {arXiv preprint arXiv:2507.00706},
  year   = {2025}
}

Comments

9 pages, 8 figures