Hyperon Polarization along the Beam Direction Relative to the Second and Third Harmonic Event Planes in Isobar Collisions at root sNN=200 GeV

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68407700%3A21340%2F23%3A00373780" target="_blank" >RIV/68407700:21340/23:00373780 - isvavai.cz</a>

Výsledek na webu

<a href="https://doi.org/10.1103/PhysRevLett.131.202301" target="_blank" >https://doi.org/10.1103/PhysRevLett.131.202301</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1103/PhysRevLett.131.202301" target="_blank" >10.1103/PhysRevLett.131.202301</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Hyperon Polarization along the Beam Direction Relative to the Second and Third Harmonic Event Planes in Isobar Collisions at root sNN=200 GeV

Popis výsledku v původním jazyce

The polarization of Lambda and (Lambda) over bar hyperons along the beam direction has been measured relative to the second and third harmonic event planes in isobar Ru thorn Ru and Zr thorn Zr collisions at root s(NN) = 200 GeV. This is the first experimental evidence of the hyperon polarization by the triangular flow originating from the initial density fluctuations. The amplitudes of the sine modulation for the second and third harmonic results are comparable in magnitude, increase from central to peripheral collisions, and show a mild p(T) dependence. The azimuthal angle dependence of the polarization follows the vorticity pattern expected due to elliptic and triangular anisotropic flow, and qualitatively disagrees with most hydrodynamic model calculations based on thermal vorticity and shear induced contributions. The model results based on one of existing implementations of the shear contribution lead to a correct azimuthal angle dependence, but predict centrality and pT dependence that still disagree with experimental measurements. Thus, our results provide stringent constraints on the thermal vorticity and shear-induced contributions to hyperon polarization. Comparison to previous measurements at RHIC and the LHC for the second-order harmonic results shows little dependence on the collision system size and collision energy.

Název v anglickém jazyce

Hyperon Polarization along the Beam Direction Relative to the Second and Third Harmonic Event Planes in Isobar Collisions at root sNN=200 GeV

Popis výsledku anglicky

The polarization of Lambda and (Lambda) over bar hyperons along the beam direction has been measured relative to the second and third harmonic event planes in isobar Ru thorn Ru and Zr thorn Zr collisions at root s(NN) = 200 GeV. This is the first experimental evidence of the hyperon polarization by the triangular flow originating from the initial density fluctuations. The amplitudes of the sine modulation for the second and third harmonic results are comparable in magnitude, increase from central to peripheral collisions, and show a mild p(T) dependence. The azimuthal angle dependence of the polarization follows the vorticity pattern expected due to elliptic and triangular anisotropic flow, and qualitatively disagrees with most hydrodynamic model calculations based on thermal vorticity and shear induced contributions. The model results based on one of existing implementations of the shear contribution lead to a correct azimuthal angle dependence, but predict centrality and pT dependence that still disagree with experimental measurements. Thus, our results provide stringent constraints on the thermal vorticity and shear-induced contributions to hyperon polarization. Comparison to previous measurements at RHIC and the LHC for the second-order harmonic results shows little dependence on the collision system size and collision energy.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10303 - Particles and field physics

Projekt

<a href="/cs/project/LM2023034" target="_blank" >LM2023034: Brookhavenská národní laboratoř – účast České republiky</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2023

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Physical Review Letters

ISSN

0031-9007

e-ISSN

1079-7114

Svazek periodika

131

Číslo periodika v rámci svazku

20

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

8

Strana od-do

—

Kód UT WoS článku

001173339200001

EID výsledku v databázi Scopus

2-s2.0-85178377560