Global polarization of Λ and (Λ)over-bar hyperons in Au plus Au collisions at root sNN=19.6 and 27GeV

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68407700%3A21340%2F23%3A00369692" target="_blank" >RIV/68407700:21340/23:00369692 - isvavai.cz</a>

Výsledek na webu

<a href="https://doi.org/10.1103/PhysRevC.108.014910" target="_blank" >https://doi.org/10.1103/PhysRevC.108.014910</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1103/PhysRevC.108.014910" target="_blank" >10.1103/PhysRevC.108.014910</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Global polarization of Λ and (Λ)over-bar hyperons in Au plus Au collisions at root sNN=19.6 and 27GeV

Popis výsledku v původním jazyce

In relativistic heavy-ion collisions, a global spin polarization, P-H, of Lambda and (Lambda) over bar hyperons along the direction of the system angular momentum was discovered and measured across a broad range of collision energies and demonstrated a trend of increasing P-H with decreasing root sNN. A splitting between Lambda and (Lambda) over bar polarization may be possible due to their different magnetic moments in a late-stage magnetic field sustained by the quark-gluon plasma which is formed in the collision. The results presented in this study find no significant splitting at the collision energies of root s(NN) = 19.6 and 27 GeV in the BNL Relativistic Heavy Ion Collisions Beam Energy Scan Phase II using the STAR detector, with an upper limit of P ((Lambda)) over bar - P-Lambda < 0.24% and P<((Lambda))over bar> - P-Lambda < 0.35%, respectively, at a 95% confidence level. We derive an upper limit on the naive extraction of the late-stage magnetic field of B < 9.4 x 10(12) T and B < 1.4 x 10(13) T at root s(NN) = 19.6 and 27 GeV, respectively, although more thorough derivations are needed. Differential measurements of P-H were performed with respect to collision centrality, transverse momentum, and rapidity. With our current acceptance of |y| < 1 and uncertainties, we observe no dependence on transverse momentum and rapidity in this analysis. These results challenge multiple existing model calculations following a variety of different assumptions which have each predicted a strong dependence on rapidity in this collision-energy range.

Název v anglickém jazyce

Global polarization of Λ and (Λ)over-bar hyperons in Au plus Au collisions at root sNN=19.6 and 27GeV

Popis výsledku anglicky

In relativistic heavy-ion collisions, a global spin polarization, P-H, of Lambda and (Lambda) over bar hyperons along the direction of the system angular momentum was discovered and measured across a broad range of collision energies and demonstrated a trend of increasing P-H with decreasing root sNN. A splitting between Lambda and (Lambda) over bar polarization may be possible due to their different magnetic moments in a late-stage magnetic field sustained by the quark-gluon plasma which is formed in the collision. The results presented in this study find no significant splitting at the collision energies of root s(NN) = 19.6 and 27 GeV in the BNL Relativistic Heavy Ion Collisions Beam Energy Scan Phase II using the STAR detector, with an upper limit of P ((Lambda)) over bar - P-Lambda < 0.24% and P<((Lambda))over bar> - P-Lambda < 0.35%, respectively, at a 95% confidence level. We derive an upper limit on the naive extraction of the late-stage magnetic field of B < 9.4 x 10(12) T and B < 1.4 x 10(13) T at root s(NN) = 19.6 and 27 GeV, respectively, although more thorough derivations are needed. Differential measurements of P-H were performed with respect to collision centrality, transverse momentum, and rapidity. With our current acceptance of |y| < 1 and uncertainties, we observe no dependence on transverse momentum and rapidity in this analysis. These results challenge multiple existing model calculations following a variety of different assumptions which have each predicted a strong dependence on rapidity in this collision-energy range.

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/LM2018109" target="_blank" >LM2018109: Brookhavenská národní laboratoř - účast České republiky</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)<br>S - Specificky vyzkum na vysokych skolach

Rok uplatnění

2023

Kód důvěrnosti údajů

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

Název periodika

PHYSICAL REVIEW C

ISSN

2469-9985

e-ISSN

2469-9993

Svazek periodika

108

Číslo periodika v rámci svazku

1

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

9

Strana od-do

—

Kód UT WoS článku

001074648700002

EID výsledku v databázi Scopus

2-s2.0-85169118736