Argonne National Laboratory

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BICEP2 and the Echoes of Cosmic Inflation

HEP Division Seminar
Walter Ogburn, Stanford University
May 14, 2014 11:00AM to 12:00PM
Building 362, Room F108
The BICEP2 team has announced the detection of degree-scale B-mode polarization of the CMB, consistent with the imprint of inflationary gravitational waves created an instant after the big bang.

The telescope is a compact refractor with a 26 cm aperture and 512 antenna-coupled TES bolometers observing at 150 GHz (2 mm). BICEP2 observed from the South Pole for three seasons from 2010 to 2012. A low-foreground region of sky with an effective area of 380 square degrees was observed to a depth of 87 nK-degrees in Stokes Q and U.

We have just announced an excess of B-mode power over the base lensed-LCDM expectation in the range inconsistent with the null hypothesis at a significance of 5. The observed B-mode power spectrum is well fit by a lensed-LCDM + tensor theoretical model with tensor/scalar ratio r=0.20+0.07-0.05, with r=0 disfavored at 7.0.