arXiv · 2511.11094
New constraints on equation of state of hot QCD matter
Abstract
The longitudinal structure of the quark-gluon plasma(QGP) remains a key challenge in heavy-ion physics. In this Letter, we propose a novel observable, event-by-event mean transverse momentum fluctuations Var$_{\langle p_{T} \rangle}$, which is sensitive to the local pressure gradients and serves as a probe of longitudinal dynamics in the initial state of QGP. We demonstrate that the covariance of averaged transverse momentum at two rapidities $\mathrm{Cov}_{\langle p_T \rangle}(\eta_1, \eta_2)$ and its associated decorrelation measures, $R_{p_T}(\eta_1, \eta_2)$ and $r_{p_T}(\eta, \eta_{\mathrm{ref}})$, exhibit strong sensitivity to the stiffness of equation of state (EoS) of QGP, while showing negligible dependence on the QGP transport coefficients. This distinctive behavior, revealed through state-of-the-art (3+1)-dimensional hydrodynamic simulations, establishes a powerful approach for constraining the EoS of QCD matter. In the meantime, our results provide new insights into the longitudinal structure of the QGP and its properties under high baryon density.
Explore related subjects
Keep this discovery
Lu-Meng Liu, Jinhui Chen, Xu-Guang Huang, Jiangyong Jia, Chun Shen, Chunjian Zhang. 2025-11-14. New constraints on equation of state of hot QCD matter. https://arxiv.org/abs/2511.11094
Cite the original work for its findings. Save a collection to share your selection of sources.