Light-Flavour Resonance Production in High-Energy Heavy-Ion Collisions: An Experimental Review

TL;DR

This review summarizes experimental measurements of light-flavour resonance production in high-energy heavy-ion collisions, highlighting how these results inform our understanding of the medium's properties and the dynamics of the hadronic phase.

Contribution

It compiles and analyzes recent experimental data on light-flavour resonances across various collision systems, emphasizing new insights into medium effects and hadronization mechanisms.

Findings

Resonance yields and properties vary with system size and multiplicity.

Medium effects include re-scattering, regeneration, and suppression.

Resonance measurements inform on the space-time evolution of the medium.

Abstract

Resonances provide sensitivity to the late-stage dynamics of heavy-ion collisions, as their lifetimes are comparable to the duration of the hadronic phase. This review summarizes state-of-the-art measurements of light-flavour mesonic and baryonic resonances, including $\rho$(770), $K^{\star}$(892), $\phi$(1020), $\Delta$(1232), $\Lambda^{\star}$(1520), $\Sigma^{\star}$(1385) and $\Xi^\star$(1530), in pp, p-A and A-A collisions at SPS, RHIC and the LHC. Systematic trends in yields, mass and width modifications, transverse-momentum spectra, nuclear modification factors, and particle ratios reveal the interplay of re-scattering and regeneration, medium-induced suppression, and the development of collective dynamics with increasing system size and multiplicity. Anisotropic flow results confirm the coupling of resonances to the expanding medium, while recent vector-meson spin-alignment measurements offer fresh insights into hadronization mechanisms and local fields. Ultra-peripheral collisions provide vacuum-like baselines for isolating in-medium effects. Emerging opportunities for charm-resonance studies in upcoming high-luminosity experiments are also outlined.Together, these advances demonstrate the important role of resonance measurements in constraining the space-time evolution of strongly interacting matter.