Feb 5 – 11, 2017
Hyatt Regency Chicago
America/Chicago timezone

Towards measurements of Chiral Magnetic (Vortical) Effect Using Identified Particles from STAR

Feb 7, 2017, 4:30 PM
Regency B

Regency B


Liwen Wen


The chiral magnetic effect (CME) and the chiral vortical effect (CVE)
have been under intensive theoretical and experimental investigations in
recent years [1]. A three-point correlator, γ [2], has been used to measure electric/baryonic charge separations across the reaction plane as the
experimental manifestation of the CME/CVE. Considerable background
sources arising from charge/momentum conservation coupled with elliptic
flow anisotropy (v2) have been identified. Disentanglement of background
and the possible CME/CVE signal has been the central focal point of theoretical and experimental efforts. We report recent progresses from the
STAR experiment in searching for the CME/CVE with identified particles
using background suppression methods. The γ correlator measurements
of π−π, π−K, p−π, K−K, p−K, p−p, p−Λ pairs are presented as a
function of centrality and beam energy in Au+Au collisions from $\sqrt{s_{NN}}$
= 7.7 to 200 GeV. We explore the range of background variations to establish where a signal may exist. We use event-shape engineering [3] as well as mixed-event subtraction as a function of the event-by-event elliptic anisotropy [4,5] to reduce the flow background. In addition, preliminary results of small system 200 GeV d+Au collisions will also be discussed. These measurements will represent a major advance in our understanding of possible CME/CVE contributions to the three-point correlation.

[1] Kharzeev, D.E. et al. Prog. Part. Nucl. Phys. 88, 1 (2016).

[2] S. A. Voloshin, Phys. Rev. C 70, 057901 (2004).

[3] F. Wen, L. Wen, G. Wang, arXiv:1608.03205.

[4] L. Adamczyk, et al. (STAR Collaboration), Phys. Rev. C 89, 044908 (2014).

[5] F. Wang, J. Zhao, arXiv:1608.06610.

Preferred Track Correlations and Fluctuations
Collaboration STAR

Primary author

Presentation materials