Abstract
Vacuum magnetic birefringence (VMB) is an anisotropy of the refractive index of the vacuum under a
magnetic field. VMB is predicted to be induced by virtual electron-positron pairs or undiscovered light
particles in the vacuum. Our OVAL experiment is trying to observe VMB with a high-finesse Fabry-
Pérot cavity and a pulsed magnet. The setup and the current status of the OVAL experiment is reported.
