Speaker
Description
The first phase of the RHIC Beam Energy Scan program (BES-I)
has revealed intriguing trends in observables as a function of
collision energy in the region $\sqrt{s_{NN}}\sim7-30$ GeV.
These include directed flow and global polarization measurements,
which require an accurate determination of the first-order event
plane. They also include measurement of higher-order moments of
the net-proton distribution, which require an accurate determination
of the collision centrality in a region well-separated from the zone
of interest at midrapidity.
The next phase of the program, BES-II, will explore this region in
greater detail, exploring additional collision energies, improving statistics,
and implementing detector upgrades. The Event Plane Detector (EPD)
is one such upgrade, providing high-segmentation charged-particle
measurements at pseudorapidy $2<|\eta|<5$. This is expected to roughly
double the first-order event plane resolution and provide a separation
$\Delta\eta\gtrsim1$ between the region used for centrality and that
used to calculate the net-baryon moments, greatly reducing
uncertainties from hadronic cross-talk.
The detector consists of two wheels, each composed of 372 tiles of
scintillator read out by wavelength-shifting fibers optically coupled to
silicon photomultipliers (SiPMs). I will discuss the detector design,
as well as results from a prototype and a partial install of the full
detector in RHIC runs 2016 and 2017, respectively. I will also discuss
the production status of the full detector, scheduled for installation
at the end of this year.
| List of tracks | New methods and facilities |
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