Speaker
Description
The $A$ Prime ($A′$) Experiment was a search performed at Hall A of the Thomas
Jefferson National Accelerator Facility (Jefferson Lab, or JLab), looking for evidence
of a dark vector gauge boson (also called a‘dark photon’). The dark
photon of interest, denoted as $A′$, is theorised to interact with the Standard
Model through kinematic mixing, which is characterised by a strength parameter,
$\varepsilon$. In February 2019, JLab’s Hall A was host to the APEX experiment,
which recorded $e^+e^-$ production from a 2.138 GeV electron beam incident on
a tungsten target. A blinded peak search was performed on 10% of the data,
which did not find any evidence of the $A′$ within the mass range 130−220 MeV,
and established the strongest limits on $A′$ production within this range. A final
peak search on the full APEX data set is currently underway, and final results
are expected in the near future.
