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SUMMARY:Vorticity and helicity fields in heavy-ion collisions and hyperon 
 polarization
DTSTART;VALUE=DATE-TIME:20220713T143000Z
DTEND;VALUE=DATE-TIME:20220713T145000Z
DTSTAMP;VALUE=DATE-TIME:20261017T215146Z
UID:indico-contribution-526@events.sinp.msu.ru
DESCRIPTION:Speakers: Nikita Tsegelnik (BLTP\, JINR\, Dubna)\nThe experime
 ntally observed significant polarization of $\\Lambda$ and anti-$\\Lambda$
  particle in heavy-in collisions [1] lead to speculations that rapidly rot
 ating swirls are of nuclear matter are created [2]. We use the transport m
 odel PHSD to simulate the Au+Au and Pb+Pb collisions at NICA energies and 
 perform the fluidization procedure determining density\, temperature\, and
  velocity fields created at different stages of the collisions. Vorticity 
 and hydrodynamic helicity fields are calculated and visualized in dynamics
 . The velocity field is illustrated on the left panel in Fig.1. It looks d
 ominantly as the Hubble-like profiles expanding in transverse and longitud
 inal directions (approximate cylindrical symmetry). The small vorticity fi
 eld looks like a small perturbation on top of the longitudinal and transve
 rse flows. The vorticity field is shown on the right panel of Fig.1. We se
 e that two vortex (asymmetrical) rings moving in the opposite direction al
 ong the $z$-axes are formed. The PHSD model is proved to describe successf
 ully hyperon yields in the broad range of collision energies of our intere
 st. Therefore\, we can calculate the polarization of (anti-)hyperons on a 
 dynamic freeze-out surface. The experimental polarization of $\\Lambda$ is
  well reproduced. However\, the anti-$\\Lambda$ polarization is underestim
 ated.\n\n![](https://events.sinp.msu.ru/event/8/abstracts/637/attachments/
 500/V3D-Au77-b75-t090-v3.png) ![](https://events.sinp.msu.ru/event/8/abstr
 acts/637/attachments/501/W3D-Au77-b75-t090-v3.png)\nFig. 1. Velocity and v
 orticity fields calculated within PHSD model for Au+Au collisions at $\\sq
 rt{s_{NN}}=7.7GeV$ for impact parameter $b=7.5fm$ at the time moment $t=7.
 7fm/c$\n\n1. L. Adamczyk et al.\, Nature 548\, 62 (2017).\n2. H. Petersen\
 , Nature 548\, 34 (2017).\n\nhttps://events.sinp.msu.ru/event/8/contributi
 ons/526/
LOCATION: НИИЯФ\, ЮК\, ауд. 3-13
URL:https://events.sinp.msu.ru/event/8/contributions/526/
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