Particle Yields in Heavy Ion Collisions and the Influence of Strong Magnetic Fields

It is expected that the magnetic fields in heavy ion collisions are very high. In this work, we investigate the effects of a strong magnetic field on particle ratios within a thermal model of particle production. We model matter as a free gas of baryons and mesons under the influence of an external magnetic field varying from zero to30mπ2through an χ2fitting to some data sets of the STAR experiment. For this purpose, we use the Dirac, Rarita-Schwinger, Klein-Gordon, and Proca equations subject to magnetic fields in order to obtain the energy expressions and the degeneracy for spin 1/2, spin 3/2, spin 0, and spin 1 particles, respectively. Our results show that, if the magnetic field can be considered as slowly varying and leaves its signature on the particle yields, a field of the order of6mπ2produces an improved fitting to the experimental data as compared to the calculations without magnetic field.

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A Systematic Study of Magnetic Field in Relativistic Heavy-Ion Collisions in the RHIC and LHC Energy Regions

Advances in High Energy Physics ◽

10.1155/2014/193039 ◽

2014 ◽

Vol 2014 ◽

pp. 1-10 ◽

Cited By ~ 29

Author(s):

Yang Zhong ◽

Chun-Bin Yang ◽

Xu Cai ◽

Sheng-Qin Feng

Keyword(s):

Magnetic Field ◽

Magnetic Fields ◽

Heavy Ion Collisions ◽

Field Model ◽

Heavy Ion ◽

Relativistic Heavy Ion Collisions ◽

Collision Time ◽

Ion Collisions ◽

200 Gev ◽

Magnetic Field Model

The features of magnetic field in relativistic heavy-ion collisions are systematically studied by using a modified magnetic field model in this paper. The features of magnetic field distributions in the central point are studied in the RHIC and LHC energy regions. We also predict the feature of magnetic fields at LHCsNN=900, 2760, and 7000 GeV based on the detailed study at RHICsNN=62.4, 130, and 200 GeV. The dependencies of the features of magnetic fields on the collision energies, centralities, and collision time are systematically investigated, respectively.

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Particle Production in Strong Electromagnetic Fields in Relativistic Heavy-Ion Collisions

Advances in High Energy Physics ◽

10.1155/2013/490495 ◽

2013 ◽

Vol 2013 ◽

pp. 1-34 ◽

Cited By ~ 214

Author(s):

Kirill Tuchin

Keyword(s):

Magnetic Field ◽

Electromagnetic Field ◽

Electromagnetic Fields ◽

Heavy Ion Collisions ◽

Particle Production ◽

Heavy Ion ◽

Relativistic Heavy Ion Collisions ◽

Ion Collisions ◽

Strong Electromagnetic Field ◽

Kinetic Coefficients

I review the origin and properties of electromagnetic fields produced in heavy-ion collisions. The field strength immediately after a collision is proportional to the collision energy and reaches ~mπ2at RHIC and ~10mπ2at LHC. I demonstrate by explicit analytical calculation that after dropping by about one-two orders of magnitude during the first fm/c of plasma expansion, it freezes out and lasts for as long as quark-gluon plasma lives as a consequence of finite electrical conductivity of the plasma. Magnetic field breaks spherical symmetry in the direction perpendicular to the reaction plane, and therefore all kinetic coefficients are anisotropic. I examine viscosity of QGP and show that magnetic field induces azimuthal anisotropy on plasma flow even in spherically symmetric geometry. Very strong electromagnetic field has an important impact on particle production. I discuss the problem of energy loss and polarization of fast fermions due to synchrotron radiation, consider photon decay induced by magnetic field, elucidateJ/ψdissociation via Lorentz ionization mechanism, and examine electromagnetic radiation by plasma. I conclude thatallprocesses in QGP are affected by strong electromagnetic field and call for experimental investigation.

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Particle Production in Heavy Ion Collisions at Intermediate Energies

HNPS Proceedings ◽

10.12681/hnps.2639 ◽

2020 ◽

Vol 15 ◽

pp. 202

Author(s):

V. Prassa ◽

T. Gaitanos ◽

H. H. Wolter ◽

G. A. Lalazissis ◽

M. Di Toro

Keyword(s):

Cross Sections ◽

Heavy Ion Collisions ◽

Particle Production ◽

Heavy Ion ◽

Nucleon Nucleon ◽

Intermediate Energies ◽

Ion Collisions ◽

Particle Ratios ◽

Rapidity Distributions ◽

Medium Modifications

We investigate the influence of the in-medium modifications of nucleon-nucleon cross sections on the particle production in heavy ion collisions at intermediate energies. In particular, it is shown that the pion and kaon yields and their rapidity distributions are strongly affected by the density dependence of the inelastic cross sections. On the other hand, the particle ratios depend less on the in-medium behavior of the inelastic cross sections.

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Very-high-energy light charged-particle production near 0° in heavy-ion collisions, 9≤E/A≤40 MeV

Physical Review C ◽

10.1103/physrevc.42.1519 ◽

1990 ◽

Vol 42 (4) ◽

pp. 1519-1529 ◽

Cited By ~ 4

Author(s):

S. Shaheen ◽

F. D. Becchetti ◽

D. A. Roberts ◽

J. W. Jänecke ◽

R. L. Stern ◽

...

Keyword(s):

Charged Particle ◽

Heavy Ion Collisions ◽

Particle Production ◽

Heavy Ion ◽

High Energy ◽

Light Charged Particle ◽

Ion Collisions ◽

Charged Particle Production ◽

Very High Energy ◽

Very High

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Particle Production in Ultrarelativistic Heavy-Ion Collisions: A Statistical-Thermal Model Review

Advances in High Energy Physics ◽

10.1155/2013/805413 ◽

2013 ◽

Vol 2013 ◽

pp. 1-27 ◽

Cited By ~ 15

Author(s):

S. K. Tiwari ◽

C. P. Singh

Keyword(s):

Thermal Model ◽

Heavy Ion Collisions ◽

Particle Production ◽

Heavy Ion ◽

Gluon Plasma ◽

Transverse Mass ◽

Current Status ◽

Thermal Models ◽

Ion Collisions ◽

Ultrarelativistic Heavy Ion Collisions

The current status of various thermal and statistical descriptions of particle production in the ultrarelativistic heavy-ion collisions experiments is presented in detail. We discuss the formulation of various types of thermal models of a hot and dense hadron gas (HG) and the methods incorporated in the implementing of the interactions between hadrons. It includes our new excluded-volume model which is thermodynamically consistent. The results of the above models together with the experimental results for various ratios of the produced hadrons are compared. We derive some new universal conditions emerging at the chemical freeze-out of HG fireball showing independence with respect to the energy as well as the structure of the nuclei used in the collision. Further, we calculate various transport properties of HG such as the ratio of shear viscosity-to-entropy using our thermal model and compare with the results of other models. We also show the rapidity as well as transverse mass spectra of various hadrons in the thermal HG model in order to outline the presence of flow in the fluid formed in the collision. The purpose of this review article is to organize and summarize the experimental data obtained in various experiments with heavy-ion collisions and then to examine and analyze them using thermal models so that a firm conclusion regarding the formation of quark-gluon plasma (QGP) can be obtained.

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Quarkonium measurements in heavy-ion collisions with the STAR experiment

EPJ Web of Conferences ◽

10.1051/epjconf/201817118015 ◽

2018 ◽

Vol 171 ◽

pp. 18015

Author(s):

Xinjie Huang

Keyword(s):

Transverse Momentum ◽

Nuclear Matter ◽

Heavy Ion Collisions ◽

Theoretical Calculations ◽

Heavy Ion ◽

Matter Effects ◽

Nuclear Modification ◽

Ion Collisions ◽

Star Experiment ◽

Nuclear Modification Factors

In these proceedings, we present the latest measurements of J/ψ and ϒ by the STAR experiment. The J/ψ and ϒ production measured in p+p collisions provide new baselines for similar measurements in Au+Au collisions, while the measurements in p+Au collisions can help quantify the cold nuclear matter effects. The J/ψ υ2 is measured in both U+U and Au+Au collisions to place constraints on the amount of J/ψ arising from recombination of deconfined charm and anti-charm pairs. Furthermore, the nuclear modification factors for ground and excited ϒ states as a function of transverse momentum and centrality are presented, and compared to those measured at the LHC as well as to theoretical calculations.

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