Time & Place: Nov. 15, Friday, 10:00am, Room 9409

Speaker: Prof. Roy Lacey, Stony Brook University (石溪大学)

Title:  Search for the Chiral Magnetic Effect with a new
charge-sensitive correlator

Abstract:  Charge separation measurements provide a crucial experimental
test for the
Chiral Magnetic Effect (CME), which in turn, could aid the development of a
detailed understanding of the chiral and topological properties of the QGP
produced in heavy-ion collisions. Such measurements have been notoriously
difficult because of the inability to cleanly separate the desired signal
from several known sources of background correlations. I will present and
discuss new measurements relative to both the $\Psi_{2}$ and $\Psi_3$ event
planes in Au+Au and  $p$($d$)+Au collisions, obtained with a new
correlator designed to mitigate these well-known backgrounds. The
correlator indicates distributions for the  measurements relative to
$\Psi_3$ and those relative to $\Psi_2$ for the $p$($d$)+Au systems,
consistent
with background-driven charge separation. By contrast, the Au+Au
measurements relative to $\Psi_2$, show event-shape-independent
distributions
expected for CME-driven charge separation, quantified by widths
inversely proportional to the Fourier dipole coefficient $\tilde{a}_1$.  The
extracted values of these widths and their dependencies on centrality and
event-shape give new constraints for CME detection in relativistic
heavy-ion collisions.