Search for Physics Beyond the Standard Model at the Jefferson Lab Eta Factory.

The Hall D Jefferson Lab Eta Factory (JEF) will collect data with the GlueX apparatus and an upgraded Forward Calorimeter (FCAL-II), which consists of a 1 m$^2$ PbWO$_4$ crystal insert in the central region of the existing FCAL. The JEF Beyond the Standard Model (BSM) physics program will search for sub-GeV dark gauge bosons (vectors, scalars, axion-like pseudo-scalars) up to 1~GeV/${\it c}^2$ in the $\eta$ and $\eta'$ decays or direct photoproductions. Some of the JEF BSM search channels and the experimental sensitivities will be discussed.