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Autori principali: Li, Feng, Liu, Shuai Y. F.
Natura: Preprint
Pubblicazione: 2022
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Accesso online:https://arxiv.org/abs/2206.11890
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author Li, Feng
Liu, Shuai Y. F.
author_facet Li, Feng
Liu, Shuai Y. F.
contents Unexpectedly large and puzzling spin alignment, and thus tensor polarization, of vector mesons has been observed in heavy-ion collisions. Given that tensor polarization represents a fluctuation of spin, we derive, for the first time, a fluctuation-dissipation relation for tensor polarization, where the polarization is proportional to first-order hydrodynamic gradients (e.g., the shear-stress tensor), with dissipative coefficients depending on the particle's damping properties, as characterized by its spectral function. Employing relativistic hydrodynamics at finite density, we find that dissipative contributions can generate substantial spin alignment. We provide illustrative examples (by tuning one coefficients $α_{\rm sh}$) that generate a beam energy, $p_T$, and centrality dependence of spin alignment resembling those observed in experiments, offering insights into these puzzling phenomena and demonstrating its potential as a ``spectrometer" for in-medium vector mesons.
format Preprint
id arxiv_https___arxiv_org_abs_2206_11890
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Tensor polarization and the dissipative damping of vector meson in QCD Medium
Li, Feng
Liu, Shuai Y. F.
Nuclear Theory
High Energy Physics - Phenomenology
Unexpectedly large and puzzling spin alignment, and thus tensor polarization, of vector mesons has been observed in heavy-ion collisions. Given that tensor polarization represents a fluctuation of spin, we derive, for the first time, a fluctuation-dissipation relation for tensor polarization, where the polarization is proportional to first-order hydrodynamic gradients (e.g., the shear-stress tensor), with dissipative coefficients depending on the particle's damping properties, as characterized by its spectral function. Employing relativistic hydrodynamics at finite density, we find that dissipative contributions can generate substantial spin alignment. We provide illustrative examples (by tuning one coefficients $α_{\rm sh}$) that generate a beam energy, $p_T$, and centrality dependence of spin alignment resembling those observed in experiments, offering insights into these puzzling phenomena and demonstrating its potential as a ``spectrometer" for in-medium vector mesons.
title Tensor polarization and the dissipative damping of vector meson in QCD Medium
topic Nuclear Theory
High Energy Physics - Phenomenology
url https://arxiv.org/abs/2206.11890