BICEP2
BICEP2 was a ground-based cosmic microwave background polarization experiment at the Amundsen–Scott South Pole Station designed to measure degree-scale B-mode polarization as a probe of primordial gravitational waves from cosmic inflation. In March 2014 the collaboration reported a high-significance B-mode signal, later shown—through joint analyses with Planck data—to be dominated by polarized Galactic dust, establishing upper limits on the tensor-to-scalar ratio rather than a detection.
