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

Yang Zhong,Xu Cai,Sheng-Qin Feng,Chun-Bin Yang

doi:10.1155/2014/193039

Abstract

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.

Highlights

Collisions of two heavy nuclei at high energy serve as a means for creating and exploring strongly interacting matter at high possible energy densities where a new extreme state of matter, the deconfined quark-gluon plasma (QGP), is expected to be formed [1,2,3]
In the short moments before/during/after the impact of two ions in noncentral collisions, there is a very strong magnetic field in the reaction zone [5,6,7]. Such a magnetic field is estimated to be of the order of mπ2 ≈ 1018 Gauss [4, 8, 9], probably the strongest, albeit transient, magnetic field in the present universe
This so-called Chiral magnetic effect may serve as a sign of the local P and CP violation of QCD

Summary

Introduction

Collisions of two heavy nuclei at high energy serve as a means for creating and exploring strongly interacting matter at high possible energy densities where a new extreme state of matter, the deconfined quark-gluon plasma (QGP), is expected to be formed [1,2,3]. The other required element, a locally nonvanishing axial charge density, can be created in the reaction zone during the collision process through sphaleron transitions (see, e.g., [10] for discussions and references therein) As such, it appears at least during the very early stage of a heavy-ion collision and there can be both strong magnetic field and nonzero axial charge density in the created hot matter. It has been shown that a strong magnetic field can convert topological charge fluctuations in the QCD vacuum into global electric charge separation with respect to the reaction plane. It is argued [26] that the CME should strongly decrease at higher energies because the magnetic field decays more rapidly Such a spread in the theoretical expectations makes it important to measure the chargedependent azimuthal correlations at the LHC, where the collision energy is an order of magnitude higher compared to the RHIC.

The Improved Calculation of Magnetic Field

Summary and Conclusion