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Description
Short-lived hadronic resonances serve as sensitive probes of the evolution of the hadronic phase in relativistic heavy-ion collisions. Among them, the $K^{*0}$ meson, with a lifetime of about $4$ fm/$c$, is particularly sensitive to hadronic rescattering and regeneration occurring between chemical and kinetic freeze-out.
In this work, we investigate the anisotropic suppression of reconstructed $K^{*0}$ resonances due to hadronic rescattering using the A Multi-Phase Transport (AMPT) model for Au+Au collisions at $\sqrt{s_{NN}}=200$ GeV. We find that the rescattering probability of the decay daughters depends strongly on the decay angle $\theta^{*}$, arising from Lorentz-boost effects that result in lower laboratory-frame momenta for daughters emitted opposite to the parent $K^{*0}$ direction. This anisotropic rescattering significantly affects experimentally accessible observables. In particular, the reconstructed $K^{*0}$ yield exhibits a pronounced dependence on $\theta^{*}$. We further show that the anisotropic loss of resonances modifies the angular distributions used to extract the spin alignment parameter $\rho_{00}$ in both the production-plane and helicity frames. Despite the absence of an intrinsic polarization mechanism in AMPT, the reconstructed $K^{*0}$ sample exhibits a significant deviation of $\rho_{00}$ from the unpolarized value of $1/3$, with opposite deviations in the two reference frames. These results demonstrate that anisotropic hadronic rescattering can generate apparent spin-alignment signals and should therefore be carefully considered in experimental measurements of vector-meson polarization.