Fourier Coefficients of Asynchronous Collective Motions in Heavy-ion Collisions

We present a novel scenario in heavy-ion collisions where different modes of collective motions evolve asynchronously in the created nuclear medium. Such physics mechanisms could each dominate at a distinct evolution stage, or coexist simultaneously without coordinating with each other. If we employ a separate single-harmonic Fourier expansion to describe how each asynchronous collective motion affects particle emission, the particle azimuthal distribution should be the product of all these expansions. Consequently, cross terms between collectivity modes appear, and their contributions to experimental observables could be significant. In particular, we argue that the chiral magnetic effect (CME) and elliptic flow can develop asynchronously, with their convolution affecting the observable that is sensitive to the shear-induced CME. We will use the event-by-event anomalous-viscous fluid dynamics model to illustrate the effects of this scenario. Besides giving new insights into searches for the CME, we also propose a feasible experimental test based on conventional flow harmonics

An Experimental Review on Heavy-Flavor v

For over a decade now, the primary purpose of relativistic heavy-ion collisions at the Relativistic Heavy-Ion Collider (RHIC) and the Large Hadron Collider (LHC) has been to study the properties of QCD matter under extreme conditions—high temperature and high density. The heavy-ion experiments at both RHIC and LHC have recorded a wealth of data in p+p, p+Pb, d+Au, Cu+Cu, Cu+Au, Au+Au, Pb+Pb, and U+U collisions at energies ranging from sNN=7.7 GeV to 7 TeV. Heavy quarks are considered good probe to study the QCD matter created in relativistic collisions due to their very large mass and other unique properties. A precise measurement of various properties of heavy-flavor hadrons provides an insight into the fundamental properties of the hot and dense medium created in these nucleus-nucleus collisions, such as transport coefficient and thermalization and hadronization mechanisms. The main focus of this paper is to present a review on the measurements of azimuthal anisotropy of heavy-flavor hadrons and to outline the scientific opportunities in this sector due to future detector upgrade. We will mainly discuss the elliptic flow of open charmed meson (D-meson), J/ψ, and leptons from heavy-flavor decay at RHIC and LHC energy

Collective Excitation in High-Energy Nuclear Collisions -- In Memory of Professor Lianshou Liu

We celebrate the legacies of our friend and mentor Professor Lianshou Liu who was one of the pioneers for the phenomenology of multi-particle interactions and initiated the physics of relativistic heavy-ion collisions in China. In this article, we discuss some of the recent exciting experimental observations on the collective phenomena including collectivity, chirality, criticality, strangeness production, and thermal equilibrium in high-energy nuclear collisions. Future directions, especially the physics at high baryon density, will be discussed with a focus on the first-order phase boundary and hyperon-nucleon interactions.Comment: 20 pages, 10 figure