The nonflow issue in connecting anisotropy measurements to hydrodynamics in relativistic heavy-ion collisions

Fuente: arXiv
Saved in:
Bibliographic Details
Main Author: Wang, Fuqiang
Format: Preprint
Published: 2024
Subjects:
Online Access:
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866914667023040512
author Wang, Fuqiang
author_facet Wang, Fuqiang
contents Hydrodynamics can describe majority of the measured azimuthal anisotropies in relativistic heavy-ion collisions. Many of the anisotropy measurements are contaminated by nonflow correlations (i.e., those unrelated to global event-wise correlations). Those nonflow contamination can cause incorrectness or compromise the accuracy of the physics extracted from data-hydrodynamics comparison, particularly when one relies on subtle difference in the measurements. In the recent preprint by STAR (arXiv:2401.06625) extracting the Uranium nucleus deformation parameter, nonflow contamination is assessed by subevents in the limited STAR acceptance. In this note, we demonstrate that such assessment is inadequate and illustrate how large an effect nonflow can cause by using the HIJING model, in which all correlations are nonflow and non-hydrodynamic. We thereby conclude that the extracted Uranium deformation parameter is premature and emphasize the importance of an earnest assessment of or correction for nonflow contamination, not only for this STAR analysis but more generally for studies relying on comparing anisotropy measurements to hydrodynamic calculations.
format Preprint
id arxiv_https___arxiv_org_abs_2402_03222
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle The nonflow issue in connecting anisotropy measurements to hydrodynamics in relativistic heavy-ion collisions
Wang, Fuqiang
Nuclear Experiment
High Energy Physics - Experiment
High Energy Physics - Phenomenology
Nuclear Theory
Hydrodynamics can describe majority of the measured azimuthal anisotropies in relativistic heavy-ion collisions. Many of the anisotropy measurements are contaminated by nonflow correlations (i.e., those unrelated to global event-wise correlations). Those nonflow contamination can cause incorrectness or compromise the accuracy of the physics extracted from data-hydrodynamics comparison, particularly when one relies on subtle difference in the measurements. In the recent preprint by STAR (arXiv:2401.06625) extracting the Uranium nucleus deformation parameter, nonflow contamination is assessed by subevents in the limited STAR acceptance. In this note, we demonstrate that such assessment is inadequate and illustrate how large an effect nonflow can cause by using the HIJING model, in which all correlations are nonflow and non-hydrodynamic. We thereby conclude that the extracted Uranium deformation parameter is premature and emphasize the importance of an earnest assessment of or correction for nonflow contamination, not only for this STAR analysis but more generally for studies relying on comparing anisotropy measurements to hydrodynamic calculations.
title The nonflow issue in connecting anisotropy measurements to hydrodynamics in relativistic heavy-ion collisions
topic Nuclear Experiment
High Energy Physics - Experiment
High Energy Physics - Phenomenology
Nuclear Theory
url https://arxiv.org/abs/2402.03222