arXiv subjects

Bang-Xiang Chen

Publications and source records attributed to Bang-Xiang Chen.

3 recordsLinked to original sources

arXiv2025

Constraining the chiral magnetic effect using spectator and participant planes across Au+Au and isobar collisions at $\sqrt{s_{_{\rm NN}}} = 200$ GeV

We investigate the chiral magnetic effect (CME) in relativistic heavy-ion collisions through an improved two-plane method analysis of the $Δγ$ observable, probing $\mathcal{CP}$-symmetry breaking in strong interactions and topological properties of the QCD vacuum. Using a multiphase transport model with tunable CME strengths, we systematically compare Au+Au and isobar collisions at $\sqrt{s_{_{\rm NN}}} = 200$ GeV. We observe a reduced difference in the CME signal-to-background ratio between the spectator and participant planes for Au+Au collisions compared to isobar collisions. A comprehensive chi-square analysis across all three collision systems reveals stronger CME signatures in Au+Au collisions relative to isobar collisions, particularly when measured with respect to the spectator plane. Our findings demonstrate an enhanced experimental reliability of the two-plane method for the CME detection in Au+Au collisions.

nucl-th↗

arXiv2024

Difference between signal and background of the chiral magnetic effect relative to spectator and participant planes in isobar collisions at $\sqrt{s_{_{\rm NN}}} = 200$ GeV

The search for the chiral magnetic effect (CME) in relativistic heavy-ion collisions helps us understand the $\mathcal{CP}$ symmetry breaking in strong interactions and the topological nature of the QCD vacuum. Since the background and signal of the CME have different correlations with the spectator and participant planes, a two-plane method has been proposed to extract the fraction of the CME signal inside the CME observable of $Δγ$ from the experimental measurements relative to the two planes. Using a multiphase transport model with different strengths of the CME, we reexamine the two-plane method in isobar collisions at $\sqrt{s_{_{\rm NN}}} = 200$ GeV. The ratios of the CME signals and the elliptic flow backgrounds relative to the two different planes are found to be different, which is inconsistent with the assumptions made in the current experimental measurements. This difference arises from the decorrelation effect of the chiral magnetic effect relative to the spectator and participant planes caused by final state interactions. Our finding suggests that the current experimental measurements may overestimate the fraction of the CME signal in the CME observable in the final state of relativistic heavy-ion collisions.

nucl-th↗

arXiv2019

A systematical study of the chiral magnetic effects at the RHIC and LHC energies

Considering the magnetic field response of the QGP medium, we perform a systematical study of the chiral magnetic effect(CME), and make a comparison it with the experimental results for the background-subtracted correlator $H$ at the energies of the RHIC Beam Energy Scan (BES) and LHC energy. The CME signals from our computations show a centrality trend and beam energy dependence that are qualitatively consistent with the experimental measurements of the charge dependent correlations. The time evolution of the chiral electromagnetic current at the RHIC and LHC energies is systematically studied. The dependence of the time-integrated current signal on the beam energy $\sqrt{s}$ with different centralities is investigated. Our phenomenological analysis shows that the time-integrated electromagnetic current is maximal near the collision energy $\sqrt{s} \approx 39$ GeV. The qualitative trend of the induced electromagnetic current is in agreement with the CME experimental results at the RHIC and LHC energies.

hep-ph↗