Disentangling flow and signals of Chiral Magnetic Effect in U+U, Au+Au and p+Au collisions

Abstract

We present STAR measurements of the charge-dependent three-particle correlator ${\gamma }^{a,b}=⟨\cos ({\varphi }_1^a+{\varphi }_2^b-2{\varphi }_3)⟩/v_2\{2\}$ and elliptic flow $v_2\{2\}$ in U+U, Au+Au and p+Au collisions at RHIC. The difference $\Delta \gamma =\gamma (\mathrm{opposite}-\mathrm{sign})-\gamma (\mathrm{same}-\mathrm{sign})$ measures charge separation across the reaction plane, a predicted signal of the Chiral Magnetic Effect (CME). Although charge separation has been observed, it has been argued that the measured separation can also be explained by elliptic flow related backgrounds. In order to separate the two effects, we perform measurements of the $\gamma$-correlator where background expectations differ from magnetic field driven effects. A differential measurement of $\gamma$ with the relative pseudorapidity ($\Delta \eta$) between the first and second particles indicate that $\Delta \gamma$ in peripheral A+A and p+A collisions are dominated by short-range correlations in $\Delta \eta$. However, a relatively wider component of the correlation in $\Delta \eta$ tends to vanish the same way as projected magnetic field as predicted by MC-Glauber simulations.

4 pages, 2 figures, proceedings for Quark Matter 2017

References in corpus (9)

• Triangularity and Dipole Asymmetry in Heavy Ion Collisions
• The ridge in proton-proton collisions at the LHC
• Beam-energy dependence of charge separation along the magnetic field in Au+Au collisions at RHIC
• Charge conservation in RHIC and contributiuons to local parity violation observables
• Observation of charge-dependent azimuthal correlations in pPb collisions and its implication for the search for the chiral magnetic effect
• Azimuthal correlations from transverse momentum conservation and possible local parity violation
• Harmonic decomposition of three-particle azimuthal correlations at RHIC
• Separation of flow from chiral magnetic effect in U+U collisions using spectator asymmetry
• Constraining the initial conditions and temperature dependent transport with three-particle correlations in Au+Au collisions

Cited by in corpus (15)

• Mapping the Phases of Quantum Chromodynamics with Beam Energy Scan
• Chiral magnetic effect reveals the topology of gauge fields in heavy-ion collisions
• Experimental searches for the chiral magnetic effect in heavy-ion collisions
• Foundations and Applications of Quantum Kinetic Theory
• Chiral Magnetic Effects in Nuclear Collisions
• A New Correlator to Detect and Characterize the Chiral Magnetic Effect
• Linearly polarized gluons and axial charge fluctuations in the Glasma
• Chiral Magnetic Effect in Heavy Ion Collisions: The Present and Future
• Search for the Chiral Magnetic Effect in Relativistic Heavy-Ion Collisions
• Examination of the observability of a chiral magnetically-driven charge-separation difference in collisions of the ${}_{44}^{96}\mathrm{Ru}+{}_{44}^{96}\mathrm{Ru}$ and ${}_{40}^{96}\mathrm{Zr}+{}_{40}^{96}\mathrm{Zr}$ isobars at energies available at RHIC
• Anomalous magnetohydrodynamics with temperature-dependent electric conductivity and application to the global polarization
• A sensitivity study of the primary correlators used to characterize chiral-magnetically-driven charge separation
• Status of CME Search Before Isobar Collisions and Methods of Blind Analysis From STAR
• Topological charge fluctuations in the Glasma
• Investigation of Experimental Observables in Search of the Chiral Magnetic Effect in Heavy-ion Collisions in the STAR experiment