Cosmic String constraints from WMAP and the South Pole Telescope

• Main Authors: Dvorkin, Cora, Wyman, Mark, Hu, Wayne
• Format: Text
• Language: unknown
• Published: arXiv 2011
• Subjects: Cosmology and Nongalactic Astrophysics astro-ph.CO; High Energy Physics - Phenomenology hep-ph; High Energy Physics - Theory hep-th; FOS Physical sciences; South Pole; South pole
• Online Access: https://dx.doi.org/10.48550/arxiv.1109.4947; https://arxiv.org/abs/1109.4947

The predictions of the inflationary LCDM paradigm match today's high-precision measurements of the cosmic microwave background anisotropy extremely well. The same data put tight limits on other sources of anisotropy. Cosmic strings are a particularly interesting alternate source to constrain. Strings are topological defects, remnants of inflationary-era physics that persist after the big bang. They are formed in a variety of models of inflation, including string theory models such as brane inflation. We assume a "Nambu-Goto" model for strings, approximated by a collection of unconnected segments with zero width, and show that measurements of temperature anisotropy by the South Pole Telescope break a parameter degeneracy in the WMAP data, permitting us to place a strong upper limit on the possible string contribution to the CMB anisotropy: the power sourced by zero-width strings must be <1.75% (95% CL) of the total or the string tension Gmu <1.7x10^{-7}. These limits imply that the best hope for detecting strings in the CMB will come from B-mode polarization measurements at arcminute scales rather than the degree scale measurements pursued for gravitational wave detection. : 8 pages, 7 figures, submitted to Phys.Rev.D, minor changes matching PRD published version