Speaker
Description
The Hall D Jefferson Lab Eta Factory (JEF) will collect 500 pb${^{-1}}$ of data between 8 and 12 GeV at incident photon-beam energies with the GlueX apparatus and an upgraded Forward Calorimeter. The JEF physics program addresses new physics and symmetry violation in hadron physics, including hadron decay dynamics. The search for sub-GeV dark particles will be performed in three different processes: (1) Primakoff-like process e.g. $\gamma p \to a p$ via $t$-channel photon exchange for axion-like particles (ALPs) coupling to photons, (2) Compton-like process e.g. $\gamma e^- \to A^{'} e^-$ for dark photons ($A^{'}$) coupling to the Standard Model charged current, and (3) $\eta^{(')}$ meson decays e.g. $\eta^{(')} \rightarrow B^{'}\gamma$ for leptophobobic gauge vector boson ($B^{'}$) coupling to the baryon number. The study of C violating $\eta^{(')}$-meson neutral decays e.g. $\eta^{(')}\rightarrow 3\gamma$ aims to further constraining CVPC new physics. The data set will enable precision tests of low-energy QCD via $\eta \rightarrow \gamma\gamma\pi^0$ which is sensitive to higher order terms of chiral perturbation theory. Among the important aspects of hadron decay dynamics are Dalitz plot analyses, in particular for the decay $\eta \rightarrow 3\pi$ which gives access to the quark mass ratio. The talk will present the physics objectives and status of the JEF experimental program.
