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Main Authors: Liu, Lu-Meng, Chen, Jinhui, Huang, Xu-Guang, Jia, Jiangyong, Shen, Chun, Zhang, Chunjian
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2511.11094
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author Liu, Lu-Meng
Chen, Jinhui
Huang, Xu-Guang
Jia, Jiangyong
Shen, Chun
Zhang, Chunjian
author_facet Liu, Lu-Meng
Chen, Jinhui
Huang, Xu-Guang
Jia, Jiangyong
Shen, Chun
Zhang, Chunjian
contents 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 $\mathrm{Cov}_{\langle p_T \rangle}(η_1, η_2)$ and its associated decorrelation measures, $R_{p_T}(η_1, η_2)$ and $r_{p_T}(η, η_{\mathrm{ref}})$, 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.
format Preprint
id arxiv_https___arxiv_org_abs_2511_11094
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle New constraints on equation of state of hot QCD matter
Liu, Lu-Meng
Chen, Jinhui
Huang, Xu-Guang
Jia, Jiangyong
Shen, Chun
Zhang, Chunjian
Nuclear Theory
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 $\mathrm{Cov}_{\langle p_T \rangle}(η_1, η_2)$ and its associated decorrelation measures, $R_{p_T}(η_1, η_2)$ and $r_{p_T}(η, η_{\mathrm{ref}})$, 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.
title New constraints on equation of state of hot QCD matter
topic Nuclear Theory
url https://arxiv.org/abs/2511.11094