The OVAL experiment: Search for Vacuum Magnetic Birefringence with a high repetitive pulsed magnet

Abst: Quantum electrodynamics (QED) predicts an anisotropy of the refractive index of the vacuum in the magnetic field. This unique property of the vacuum is referred to as vacuum magnetic birefringence (VMB), which is induced by the non-linear interaction of photons mediated by the virtual electron-positron pairs in the vacuum. In addition, Axion like particles and milli-charged particles are also predicted to induce VMB. Experimental observation of VMB is a good probe for new physics beyond the standard model as well as a precision test of QED. The OVAL experiment searches for VMB with a high repetitive pulsed magnet and a high finesse optical cavity. In this talk, I would like to show the latest result of the OVAL experiment.

Probing the structure of the vacuum with light source: a good probe for the structure of the vacuum 1.low e collider 2.selectively excitation spin 0 3. high precesion

VMB: anisotropy of the refractive index of the vac in the B field

candidate: virtual e-positron pair in vac contribution from axion, couples to 2 photons

Motivation: 1. VMB by QED 2. new phy

fabry-perot cavity

setup

history of VMB search

PVLAS

one order worse than the over of the QED effect

- weak B - unexpecte biref noise in low freq

pulsed mag for VMB search

key point 1 : pulse mag

1064 nm CW –> reflectivity of the mirrors