Cosmic birefringence is a potential mechanism that can rotate the linear polarization of light as it propagates through space.
By analyzing the oldest polarized light in the universe, the Cosmic Microwave Background, we can put tight constraints on this effect.
In this talk, we will discuss what cosmic birefringence is and present new measurements of it using the Planck polarized data.
Our findings point to a 3-sigma detection of cosmic birefringence.
If the measurement is confirmed as a cosmic signal, this would provide evidence for physics beyond the standard model of particle physics.
