New BBN limits on Physics Beyond the Standard Model from He4

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A recent analysis of the He4 abundance determined from observations of extragalactic HII regions indicates a significantly greater uncertainty for the He4 mass fraction. The derived value is now in line with predictions from big bang nucleosynthesis when the baryon density determined by WMAP is assumed. Based on this new analysis of He4, we derive constraints on a host of particle properties which include: limits on the number of relativistic species at the time of BBN (commonly taken to be the limit on neutrino flavors), limits on the variations of fundamental couplings such as alpha_{em} and G_N, and limits on decaying particles.
17 pages, 5 ps figures

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Astrophysics

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http://salesiana.dossiersoluciones.com/handle/123456789/177104

Consulte el texto completo en el siguiente enlace:

https://arxiv.org/abs/astro-ph/0408033
 http://arxiv.org/abs/astro-ph/0408033
 Astropart.Phys.23:313-323,2005
 doi:10.1016/j.astropartphys.2005.01.005

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arXiv