New BBN limits on physics beyond the standard model from 4He

By Richard H. Cyburt, B. Fields, K. Olive, E. Skillman. 2004

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A recent analysis of the 4He abundance determined from observations of extragalactic HII regions indicates a significantly greater uncertainty for the 4He mass fraction. Furthermore, due to a different treatment of systematic effects such as underlying stellar absorption, the derived value of the 4He abundance is slightly higher. As a result, the predicted value of the primordial 4He abundance is now in line with calculations from big bang nucleosynthesis when the baryon density determined by WMAP is assumed. Analysis based on prior estimates of the 4He abundance will necessarily lead to constraints which are overly restrictive. Based on this new analysis of 4He, 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 αem and GN, and limits on decaying particles.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/cfc14a75fe38115008bd0b2f6b75fc10c0c0efd3

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Citations in the corpus

THE ATACAMA COSMOLOGY TELESCOPE: COSMOLOGICAL PARAMETERS FROM THE 2008 POWER SPECTRUM (2010, background): “BBN observations limit Neff to 3.24± 0.6 (Cyburt et al. 2005).”
The astrophysical gravitational wave stochastic background (2011, methodology): “Measurements of the light element abundances combined with the WMAP data givesNν < 4.4 (Cyburt et al. 2005), which translates to Ωgw < 1.5× 10−5.”
Revised Primordial Helium Abundance Based on New Atomic Data (2007, background): “Moreover, our Yp value, if our error budget is correct, provides stronger constraints to some predictions of nonstandard big bang cosmologies than previous studies (e.g., Cyburt et al. 2005; Coc et al. 2006 and references therein).”
A new approach to systematic uncertainties and self-consistency in helium abundance determinations (2010, background): “In addition to lending itself to scrutiny by comparing the predictions of BBN with observations, the resulting abundances are of significant scientific value in constraining the content and interactions of the universe during BBN (Malaney & Mathews 1993; Sarkar 1996; Cyburt et al. 2005).”
Observable non-gaussianity from gauge field production in slow roll inflation, and a challenging connection with magnetogenesis (2012, background): “Secondly, one may try to arrange for a time evolution of I during reheating in such a way that ephysical is brought from a very tiny value at the end of inflation (so to avoid the strong coupling problem during inflation) to the present value before the onset of Big-Bang Nucleosynthesis (given that ”
Leptogenesis as a common origin for matter and dark matter (2009, methodology): “A reliable bound is �Nν ≤ 1.44 at 95% CL by various present observations [ 62 , 63].”
The Primordial Abundance of 4He: A Self-consistent Empirical Analysis of Systematic Effects in a Large Sample of Low-Metallicity H II Regions (2007, background): “These lower estimates of Yp have led some authors to argue that the discrepancy between the values of b derived from Yp and from D/H is a sign that SBBN is not valid (Chen et al. 2001; Kneller et al. 2001; Barger et al. 2003a, 2003b; Cyburt et al. 2005) and that new physics are required.”
The four basic ways of creating dark matter through a portal (2011, unknown): “This is usually phrased in terms of limits on the number of neutrino families [31, 32] which, at 95 % C.”