Early Universe Constraints On Physics Beyond The Standard Model
by
Gary Steigman(Columbus, Ohio)
→
Europe/Berlin
Hoersaal (MPI)
Hoersaal
MPI
Description
Big Bang Nucleosynthesis (BBN) is a key pillar of modern cosmology, providing a probe of the particle content and expansion rate of the Universe a mere few minutes after the beginning. The observationally inferred primordial abundances of Deuterium and Helium-4, when compared to the BBN predictions, provide an excellent baryometer and chronometer, respectively. Helium-4 is sensitive to the neutrino content of the Universe and is a window onto any asymmetry between neutrinos and antineutrinos and, a probe of the early Universe expansion rate. On the other hand, the spectrum of temperature fluctuations imprinted on the Cosmic Microwave Background radiation (CMB), is sensitive to the baryon density and to the expansion rate some 400 thousand years later in the evolution of the Universe. The complementary constraints imposed by BBN and the CMB are reviewed, revealing a consistent picture of the Universe at two very widely separated epochs, leading to new, tighter constraints on the baryon density at present and on possible new physics beyond the standard models of particle physics and cosmology.