The global polarization of the and hyperons is measured for Pb-Pb collisions at √sNN = 2.76 and 5.02 TeV recorded with the ALICE at the Large Hadron Collider (LHC). The results are reported differentially as a function of collision centrality and hyperon’s transverse momentum (pT ) for the range of centrality 5–50%, 0.5 < pT < 5 GeV/c, and rapidity |y| < 0.5. The hyperon global polarization averaged for Pb-Pb collisions at √sNN = 2.76 and 5.02 TeV is found to be consistent with zero, PH (%) ≈ 0.01 ± 0.06 (stat.) ± 0.03 (syst.) in the collision centrality range 15–50%, where the largest signal is expected. The results are compatible with expectations based on an extrapolation from measurements at lower collision energies at the Relativistic Heavy Ion Collider, hydrodynamical model calculations, and empirical estimates based on collision energy dependence of directed flow, all of which predict the global polarization values at LHC energies of the order of 0.01%.

Global polarization of ΛΛ¯ hyperons in Pb-Pb collisions at sNN= 2.76 and 5.02 TeV

Barbera, R.;La Rocca, P.;Pinto, C.;Riggi, F.;
2020

Abstract

The global polarization of the and hyperons is measured for Pb-Pb collisions at √sNN = 2.76 and 5.02 TeV recorded with the ALICE at the Large Hadron Collider (LHC). The results are reported differentially as a function of collision centrality and hyperon’s transverse momentum (pT ) for the range of centrality 5–50%, 0.5 < pT < 5 GeV/c, and rapidity |y| < 0.5. The hyperon global polarization averaged for Pb-Pb collisions at √sNN = 2.76 and 5.02 TeV is found to be consistent with zero, PH (%) ≈ 0.01 ± 0.06 (stat.) ± 0.03 (syst.) in the collision centrality range 15–50%, where the largest signal is expected. The results are compatible with expectations based on an extrapolation from measurements at lower collision energies at the Relativistic Heavy Ion Collider, hydrodynamical model calculations, and empirical estimates based on collision energy dependence of directed flow, all of which predict the global polarization values at LHC energies of the order of 0.01%.
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/20.500.11769/413952
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 25
  • ???jsp.display-item.citation.isi??? 26
social impact