Core-corona approach to describe hyperon global polarization in semi-central relativistic heavy-ion collisions

Authors

DOI:

https://doi.org/10.31349/SuplRevMexFis.4.021109

Keywords:

Hyperon Polarization, Core, Corona, Directed Flow

Abstract

We report on the core-corona model developed to describe the main features of hyperon global polarization in semicentral relativistic heavy-ion collisions as a function of the collision energy. We first neglect the contribution to polarization from hyperons produced in the corona. In this scenario, the global polarization turns out to be described by a delicate balance between the vorticity-to-spin transferring reactions in the core and the predominance of corona over core matter at low energies. We show how this last feature provides a key ingredient missing in our original model that helps to better describe the excitation function for Λ and Λ global polarization. To improve the description, we then introduce the contribution to the global polarization coming from the transverse polarization of Λs produced in the corona, which is hereby assumed to be similar to the well-known polarization produced in p + p reactions. The results show a small positive contribution to the global polarization, however they are not yet conclusive due to the small size of the MC sample used in the analysis.

References

A.Ayala et al., Λ 0 polarization as a probe for production of deconfined matter in ultrarelativistic heavy ion collisions, Phys. Rev. C 65 (2002) 024902, https://doi.org/10.1103/PhysRevC.65.024902

L. Adamczyk et al., Global Λ hyperon polarization in nuclear collisions: evidence for the most vortical fluid, Nature 548 (2017) 62, https://doi.org/10.1038/nature23004

M. S. Abdallah et al., Global Λ-hyperon polarization in Au+Au collisions at √ sNN = 3 GeV, Phys. Rev. C 104 (2021) L061901, https://doi.org/10.1103/PhysRevC.104.L061901

R. Abou Yassine et al., Measurement of global polarization of Λ hyperons in few-GeV heavy-ion collisions, Phys. Lett. B 835 (2022) 137506, https://doi.org/10.1016/j.physletb.2022.137506

A. Ayala et al., Core meets corona: A two-component source to explain Λ and Λ¯ global polarization in semi-central heavyion collisions, Phys. Lett. B 810 (2020) 135818, https://doi.org/10.1016/j.physletb.2020.135818

A. Ayala et al., Rise and fall of Λ and Λ¯ global polarization in semi-central heavy-ion collisions at HADES, NICA and RHIC energies from the core-corona model, Phys. Rev. C 105 (2022) 034907, https://doi.org/10.1103/PhysRevC.105.034907

F. Becattini and J. Manninen, Centrality dependence of strangeness production in heavy-ion collisions as a geometrical effect of core-corona superposition, Phys. Lett. B 673 (2009) 19, https://doi.org/10.1016/j.physletb.2009.01.066

J. Aichelin and K. Werner, Is the centrality dependence of the elliptic flow v2 and of the average < pT > more than a Core- Corona Effect?, Phys. Rev. C 82 (2010) 034906, https://doi.org/10.1103/PhysRevC.82.034906

A. Ayala et al., Λ and Λ¯ global polarization from the corecorona model, Rev. Mex. Fis. Suppl. 3 (2022) 040914, https://doi.org/10.31349/SuplRevMexFis.3.040914

A. Ayala et al., Relaxation time for the alignment between the spin of a finite-mass quark or antiquark and the thermal vorticity in relativistic heavy-ion collisions, Phys. Rev. D 102 (2020) 056019, https://doi.org/10.1103/PhysRevD.102.056019

A. Ayala et al., Relaxation time for quark spin and thermal vorticity alignment in heavy-ion collisions, Phys. Lett. B 801 (2020) 135169, https://doi.org/10.1016/j.physletb.2019.135169

V. Abgaryan et al., Status and initial physics performance studies of the MPD experiment at NICA, Eur. Phys. J. A 58 (2022) 140, https://doi.org/10.1140/epja/s10050-022-00750-6

M. Ablikim et al., Polarization and Entanglement in BaryonAntibaryon Pair Production in Electron-Positron Annihilation, Nature Phys. 15 (2019) 631, https://doi.org/10.1038/s41567-019-0494-8

T. A. DeGrand and H. I. Miettinen, Quark Dynamics of Polarization in Inclusive Hadron Production, Phys. Rev. D 23 (1981) 1227, https://doi.org/10.1103/PhysRevD.23.1227

T. A. DeGrand and H. I. Miettinen, Models for Polarization Asymmetry in Inclusive Hadron Production, Phys. Rev. D 24 (1981) 2419, https://doi.org/10.1103/PhysRevD.24.2419

T. Fujita and T. Matsuyama, A Comment on the Degrandmiettinen Model for the Polarization of Λ in Proton Proton Collisions, Phys. Rev. D 38 (1988) 401, https://doi.org/10.1103/PhysRevD.38.401

Y. Kitsukawa and K. Kubo, Hadron spin polarization produced by a dynamical spin-orbit interaction, Prog. Theor. Phys. 103 (2000) 1173, https://doi.org/10.1143/PTP.103.1173

A. Smith et al., Λ 0 Polarization in Proton Proton Interactions From √ s = 33 GeV to 62 GeV, Phys. Lett. B 185 (1987) 209, https://doi.org/10.1016/0370-2693(87)91556-5

V. Blobel et al., Transverse Momentum Dependence in Proton Proton Interactions at 24 GeV/c, Nucl. Phys. B 122 (1977) 429, https://doi.org/10.1016/0550-3213(77)90137-7

M. Asai et al., Inclusive K0 S, Λ and Λ Production in 360- GeV/cpp Interactions Using the European Hybrid Spectrometer, Z. Phys. C 27 (1985) 11, https://doi.org/10. 1007/BF01642475

K. Jaeger et al., Characteristics of V 0 and γ Production in pp Interactions at 205 GeV/c, Phys. Rev. D 11 (1975) 2405, https://doi.org/10.1103/PhysRevD.11.2405

J. Adam et al., Beam energy dependence of rapidityeven dipolar flow in Au+Au collisions, Phys. Lett. B 784 (2018) 26, https://doi.org/10.1016/j.physletb.2018.07.013

F. G. Gardim et al., Directed flow at mid-rapidity in event-byevent hydrodynamics, Phys. Rev. C 83 (2011) 064901, https://doi.org/10.1103/PhysRevC.83.064901

B. Abelev et al., Directed Flow of Charged Particles at Midrapidity Relative to the Spectator Plane in Pb-Pb Collisions at √ sNN = 2.76 TeV, Phys. Rev. Lett. 111 (2013) 232302, https://doi.org/10.1103/PhysRevLett.111.232302

M. Luzum and J.-Y. Ollitrault, Directed flow at midrapidity in heavy-ion collisions, Phys. Rev. Lett. 106 (2011) 102301, https://doi.org/10.1103/PhysRevLett.106.102301

D. Teaney and L. Yan, Triangularity and Dipole Asymmetry in Heavy Ion Collisions, Phys. Rev. C 83 (2011) 064904, https://doi.org/10.1103/PhysRevC.83.064904

S. A. Bass et al., Microscopic models for ultrarelativistic heavy ion collisions, Prog. Part. Nucl. Phys. 41 (1998) 255, https://doi.org/10.1016/S0146-6410(98)00058-1

M. Bleicher et al., Relativistic hadron hadron collisions in the ultrarelativistic quantum molecular dynamics model, J. Phys. G 25 (1999) 1859, https://doi.org/10.1088/0954-3899/25/9/308

J. Steinheimer and M. Bleicher, Core-corona separation in the UrQMD hybrid model, Phys. Rev. C 84 (2011) 024905, https://doi.org/10.1103/PhysRevC.84.024905

H. Petersen et al., Fully Integrated Transport Approach to Heavy Ion Reactions with an Intermediate Hydrodynamic Stage, Phys. Rev. C 78 (2008) 044901, https://doi.org/10.1103/PhysRevC.78.044901

D. H. Rischke, S. Bernard, and J. A. Maruhn, Relativistic hydrodynamics for heavy ion collisions. 1. General aspects and expansion into vacuum, Nucl. Phys. A 595 (1995) 346, https://doi.org/10.1016/0375-9474(95)00355-1

D. H. Rischke, Y. Pürsün, and J. A. Maruhn, Relativistic hydro- ¨ dynamics for heavy ion collisions. 2. Compression of nuclear matter and the phase transition to the quark - gluon plasma, Nucl. Phys. A 595 (1995) 383, https://doi.org/10.1016/0375-9474(95)00356-3

E. Nazarova et al., Study of hyperon global polarization at MPD (2022), URL https://indico.oris.mephi.ru/event/298/session/1/contribution/12, Workshop on physics performance studies at NICA (NICA-2022)

M. Abdallah √ et al., Disappearance of partonic collectivity in sNN = 3 GeV Au+Au collisions at RHIC, Physics Letters B 827 (2022) 137003, https://doi.org/10.1016/j.physletb.2022.137003

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Published

2023-09-30

How to Cite

1.
Ayala A, Domínguez I, Maldonado Cervantes IA, Tejeda-Yeomans M-E. Core-corona approach to describe hyperon global polarization in semi-central relativistic heavy-ion collisions. Supl. Rev. Mex. Fis. [Internet]. 2023 Sep. 30 [cited 2023 Dec. 10];4(2):021109 1-5. Available from: https://rmf.smf.mx/ojs/index.php/rmf-s/article/view/7014