First measurement of quarkonium polarization in nuclear collisions at the LHC

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68378271%3A_____%2F21%3A00541978" target="_blank" >RIV/68378271:_____/21:00541978 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/61389005:_____/21:00541978 RIV/68407700:21340/21:00351208

Výsledek na webu

<a href="https://doi.org/10.1016/j.physletb.2021.136146" target="_blank" >https://doi.org/10.1016/j.physletb.2021.136146</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.physletb.2021.136146" target="_blank" >10.1016/j.physletb.2021.136146</a>

Jazyk výsledku

angličtina

Název v původním jazyce

First measurement of quarkonium polarization in nuclear collisions at the LHC

Popis výsledku v původním jazyce

The polarization of inclusive J/psi and Upsilon(1S) produced in Pb-Pb collisions at root s(NN) = 5.02 TeV at the LHC is measured with the ALICE detector. The study is carried out by reconstructing the quarkonium through its decay to muon pairs in the rapidity region 2.5 < y < 4 and measuring the polar and azimuthal angular distributions of the muons. The polarization parameters lambda(theta), lambda(phi) and lambda(theta phi) are measured in the helicity and Collins-Soper reference frames, in the transverse momentum interval 2 < p(T) < 10 GeV/c and p(T) < 15 GeV/c for the J/psi and Upsilon(1S), respectively. The polarization parameters for the J/psi are found to be compatible with zero, within a maximum of about two standard deviations at low p(T), for both reference frames and over the whole p(T) range. The values are compared with the corresponding results obtained for pp collisions at root s = 7 and 8 TeV in a similar kinematic region by the ALICE and LHCb experiments. Although with much larger uncertainties, the polarization parameters for Upsilon(1S) production in Pb-Pb collisions are also consistent with zero.

Název v anglickém jazyce

First measurement of quarkonium polarization in nuclear collisions at the LHC

Popis výsledku anglicky

The polarization of inclusive J/psi and Upsilon(1S) produced in Pb-Pb collisions at root s(NN) = 5.02 TeV at the LHC is measured with the ALICE detector. The study is carried out by reconstructing the quarkonium through its decay to muon pairs in the rapidity region 2.5 < y < 4 and measuring the polar and azimuthal angular distributions of the muons. The polarization parameters lambda(theta), lambda(phi) and lambda(theta phi) are measured in the helicity and Collins-Soper reference frames, in the transverse momentum interval 2 < p(T) < 10 GeV/c and p(T) < 15 GeV/c for the J/psi and Upsilon(1S), respectively. The polarization parameters for the J/psi are found to be compatible with zero, within a maximum of about two standard deviations at low p(T), for both reference frames and over the whole p(T) range. The values are compared with the corresponding results obtained for pp collisions at root s = 7 and 8 TeV in a similar kinematic region by the ALICE and LHCb experiments. Although with much larger uncertainties, the polarization parameters for Upsilon(1S) production in Pb-Pb collisions are also consistent with zero.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10303 - Particles and field physics

Projekt

Výsledek vznikl pri realizaci vícero projektů. Více informací v záložce Projekty.

Návaznosti

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

Rok uplatnění

2021

Kód důvěrnosti údajů

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

Název periodika

Physics Letters. B

ISSN

0370-2693

e-ISSN

1873-2445

Svazek periodika

815

Číslo periodika v rámci svazku

APR

Stát vydavatele periodika

NL - Nizozemsko

Počet stran výsledku

13

Strana od-do

136146

Kód UT WoS článku

000632729200048

EID výsledku v databázi Scopus

2-s2.0-85101795363