Spin dynamics with realistic hydrodynamic background for relativistic heavy-ion collisions

Fuente: arXiv
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Main Authors: Singh, Sushant K., Ryblewski, Radoslaw, Florkowski, Wojciech
Format: Preprint
Published: 2024
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author Singh, Sushant K.
Ryblewski, Radoslaw
Florkowski, Wojciech
author_facet Singh, Sushant K.
Ryblewski, Radoslaw
Florkowski, Wojciech
contents The equations of perfect spin hydrodynamics are solved for the first time using a realistic (3+1)-dimensional hydrodynamic background, calibrated to reproduce a comprehensive set of hadronic observables, including rapidity distributions, transverse momentum spectra, and elliptic flow coefficients for Au+Au collisions at the beam energy of $\sqrt{s_{\rm NN}} = 200$ GeV. The spin dynamics is governed by the conservation of the spin tensor, describing spin-$\frac{1}{2}$ particles, with particle mass in the spin tensor treated as an effective parameter. We investigate several scenarios, varying both the effective mass and the initial evolution time for the spin polarization tensor. The model predictions are then compared with experimental measurements of global and longitudinal spin polarization of Lambda hyperons. Our results indicate that a successful description of the data requires a delayed initial evolution time for the perfect spin hydrodynamics of about 4 fm/$c$ (in contrast to the standard initial time of 1 fm/$c$ used for the hydrodynamic background). This delay marks a transition from the phase where spin-orbit interaction is significant to the regime where spin-conserving processes dominate. Our findings suggest that the spin-orbit dissipative interaction plays a significant role only in the very early stages of the system's evolution.
format Preprint
id arxiv_https___arxiv_org_abs_2411_08223
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Spin dynamics with realistic hydrodynamic background for relativistic heavy-ion collisions
Singh, Sushant K.
Ryblewski, Radoslaw
Florkowski, Wojciech
High Energy Physics - Phenomenology
Nuclear Theory
The equations of perfect spin hydrodynamics are solved for the first time using a realistic (3+1)-dimensional hydrodynamic background, calibrated to reproduce a comprehensive set of hadronic observables, including rapidity distributions, transverse momentum spectra, and elliptic flow coefficients for Au+Au collisions at the beam energy of $\sqrt{s_{\rm NN}} = 200$ GeV. The spin dynamics is governed by the conservation of the spin tensor, describing spin-$\frac{1}{2}$ particles, with particle mass in the spin tensor treated as an effective parameter. We investigate several scenarios, varying both the effective mass and the initial evolution time for the spin polarization tensor. The model predictions are then compared with experimental measurements of global and longitudinal spin polarization of Lambda hyperons. Our results indicate that a successful description of the data requires a delayed initial evolution time for the perfect spin hydrodynamics of about 4 fm/$c$ (in contrast to the standard initial time of 1 fm/$c$ used for the hydrodynamic background). This delay marks a transition from the phase where spin-orbit interaction is significant to the regime where spin-conserving processes dominate. Our findings suggest that the spin-orbit dissipative interaction plays a significant role only in the very early stages of the system's evolution.
title Spin dynamics with realistic hydrodynamic background for relativistic heavy-ion collisions
topic High Energy Physics - Phenomenology
Nuclear Theory
url https://arxiv.org/abs/2411.08223