Conveners
Chirality, vorticity and polarisation effects: I
- Bedangadas Mohanty (National Institute of Science Education and Research (IN))
Chirality, vorticity and polarisation effects: II
- Alexander Sorin (Joint Institute for Nuclear Research (RU))
Chirality, vorticity and polarisation effects: III
- Rene Bellwied (University of Houston (US))
The matter created in non-central heavy-ion collisions is expected to possess a significant fraction of the initial angular momentum carried by the two colliding nuclei. This angular momentum can lead to vorticity of the system and be partially transferred to the spin of produced particles due to the spin-orbit coupling, leading to the phenomenon of global polarization. The STAR Collaboration...
Large magnetic field and large angular momentum are expected to be present in the initial stages of high-energy heavy-ion collisions. One of the physics interests of the heavy-ion program using the ALICE detector at the LHC is to look for signatures of these effects. This can be achieved by studying the angular distributions of the decay daughters of hyperons and vector mesons.
We present new...
In hydrodynamic picture of heavy ion collisions, local thermal vorticity of the QGP fluid leads to polarization of nonzero spin hadrons produced out of it [1]. The nonzero polarization of $\Lambda$ hyperons has been recently discovered by STAR in non-central Au-Au collisions in RHIC Beam Energy Scan program [2].
We further study the predictions of the hydrodynamic model for different...
Relativistic thermodynamics with spin provided the polarization 4-vector to characterize the spin alignment in rotating systems. Based on a Yang-Mills flux-tube initial state and a high-resolution, (3+1)D particle-in-cell relativistic (PICR) hydrodynamics simulation, we numerically obtain the polarization vector for $\Lambda$ hyperons at NICA and FAIR energies, and find that the $y$ component...
A new framework for relativistic hydrodynamics with spin is proposed. It is based on the conservation laws for charge, energy, momentum, and angular momentum. The conservation laws lead to hydrodynamic equations for the charge density, local temperature, and fluid velocity, as well as for the spin polarization tensor. The resulting set of differential equations extends the standard picture of...
Searches for the chiral magnetic effect (CME) using charge-dependent azimuthal correlations with respect to event planes are presented in PbPb collisions at 5.02 TeV and pPb collisions at 5.02 and 8.16 TeV, with the CMS experiment at the LHC. The azimuthal correlations with respect to the second- and third-order event planes are explored as a function of pseudorapidity, transverse momentum,...
Due to the topology of QCD vacuum, a strong magnetic field can lead to an electric current, or charge separation in heavy ion collisions, a phenomenon called chiral magnetic effect (CME). Finite azimuthal correlator ($\Delta\gamma$) signals have been measured in experiments, consistent with the CME, but contaminated by a major elliptic flow ($v_{2}$) induced background. The isobaric...
Using two novel methods, pair invariant mass ($m_{inv}$) [1] and comparative measurements with respect to reaction plane ($\psi_{\rm RP}$) and participant plane ($\psi_{\rm PP}$) [2], we isolate the chiral magnetic effect (CME) from backgrounds in 200 GeV Au+Au collisions at STAR.
The invariant mass method identifies the resonance background contributions, coupled with the elliptic flow...
Chiral Magnetic Effect (CME) is the macroscopic manifestation of the fundamental chiral anomaly in a many-body system of chiral fermions, and emerges as a generic anomalous transport current in the hydrodynamic framework. The study of CME has attracted significant recent interest across many disciplines from condensed matter to nuclear physics. ***An experimental observation of CME in...
The strong magnetic field generated by colliding nuclei could create a current in the QGP medium resulting in charge separation along the direction of the magnetic field which is perpendicular to the reaction plane. This phenomenon is called the chiral magnetic effect (CME). Initial studies by ALICE showed that the magnitude of the three particle correlator used in the search for the CME is...
The chiral kinetic theory (CKT) is a useful tool to investigate anomalous transport pertinent to quantum anomalies in and out of equilibrium for weyl-fermion systems, which has been widely applied to study chiral magnetic/vortical effects (CME/CVE) in heavy ion collisions (HIC). However, there exist some fundamental issues such as Lorentz covariance and systematic inclusion of collisions in...
The strong magnetic fields induced by heavy-ion collisions have attracted a lot of interests in transport phenomena in QGP. While the roles of the chiral fermions played in the anomaly-induced transport phenomena have been intensively investigated, their manifestations in the dissipative transport phenomena have not been fully identified. We discuss the heavy-quark diffusion dynamics [1],...
The chiral magnetic wave (CMW) has been theorized to propagate in the Quark-Gluon Plasma formed in high-energy heavy-ion collisions. It could cause a finite electric quadrupole moment of the collision system, and may be observed by charge asymmetry, $A_{\rm ch}$, dependence of elliptic flow of positively and negatively charged hadrons. However, non-CMW mechanisms such as Local charge...
The quark-gluon plasma created in heavy ion collisions is a relativistic fluid with extremely large acceleration and vorticity, as demonstrated by the recent STAR measurement of Lambda polarization.
In local equilibrium conditions, the standard hydrodynamic stress-energy tensor expression is expected to receive corrections proportional to the square of acceleration and vortiicty.
We show...
The large initial global angular momentum in non-central collisions, when acting together with spin-orbital coupling, can lead to global polarization of produced quarks. Such effect eventually manifests itself as non-vanishing polarization of hardrons with non-zero spin. Vector mesons, unlike hyperons which have large contributions from resonance decay, are originated predominantly from...
The Chiral Magnetic Effect (CME) refers to charge separation along a strong magnetic field, due to topological charge fluctuations in QCD. Charge correlation ($\Delta\gamma$) signals consistent with CME have been first observed almost a decade ago. It has also been known since then that the $\Delta\gamma$ was contaminated by a major background from resonance decays coupled with the elliptic...
