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I show that neutral lithium couples strongly to the cosmic microwave background (CMB) through its 6708A resonant transition after it recombines at z~500. At observed wavelengths of <335 micron, the CMB anisotropies are significantly altered…

Astrophysics · Physics 2009-11-06 Abraham Loeb

We discuss how much we can probe the effective number of neutrino species N_nu with cosmic microwave background alone. Using the data of WMAP, ACBAR, CBI and BOOMERANG experiments, we obtain a constraint on the effective number of neutrino…

Astrophysics · Physics 2008-11-26 Kazuhide Ichikawa , Toyokazu Sekiguchi , Tomo Takahashi

Big-bang nucleosynthesis (BBN) theory, together with the precise WMAP cosmic baryon density, makes tight predictions for the abundances of the lightest elements. Deuterium and 4He measurements agree well with expectations, but 7Li…

Cosmology and Nongalactic Astrophysics · Physics 2012-03-19 Brian D. Fields

We take a fresh look at the limits on the number of neutrino flavors derived from big bang nucleosynthesis. In particular, recent measurements of the \he4 abundance enable one to estimate the primordial \he4 mass fraction at $Y_p = 0.232…

High Energy Physics - Phenomenology · Physics 2016-09-01 Keith A. Olive , Gary Steigman

We show that the predicted primordial helium production is significantly reduced when new measurements of the neutron lifetime and the implied enhancement in the weak reaction rates are included in big-bang nucleosynthesis. Therefore, even…

Astrophysics · Physics 2009-11-10 G. J. Mathews , T. Kajino , T. Shima

The anisotropies of the cosmic microwave background (CMB) are computed for the half-turn space E_2 which represents a compact flat model of the Universe, i.e. one with finite volume. This model is inhomogeneous in the sense that the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 R. Aurich , S. Lustig

From the observations of the anisotropies of the Cosmic Microwave Background (CMB) radiation, the WMAP satellite has provided a determination of the baryonic density of the Universe, \Omega_b.h^2, with an unprecedented precision. This…

Anisotropies in the Cosmic Microwave Background (CMB) contain a wealth of information about the past history of the universe and the present values of cosmological parameters. I ouline some of the theoretical advances of the last few years.…

Astrophysics · Physics 2007-05-23 Scott Dodelson

The connection between cosmological observations and neutrino physics is discussed in detail. Neutrinos decouple from thermal contact in the early Universe at a temperature of order 1 MeV which coincides with the temperature where light…

High Energy Physics - Phenomenology · Physics 2008-11-26 Steen Hannestad

We investigate how large lepton asymmetries affect the evolution of the early universe at times before big bang nucleosynthesis and in particular how they influence the relic density of WIMP dark matter. In comparison to the standard…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 Maik Stuke , Dominik J Schwarz , Glenn Starkman

The recent analysis of the cosmic microwave background data carried out by the WMAP team seems to show that the sum of the neutrino masses is <0.7 eV. However, this result is not model-independent, depending on precise assumptions on the…

Astrophysics · Physics 2009-11-10 Massimiliano Lattanzi

These lecture notes comprise an informal but pedagogical introduction to the well established physics and phenomenology of the cosmic microwave background (CMB) between big bang nucleosynthesis and recombination. The dominant properties of…

Astrophysics · Physics 2008-02-26 Wayne Hu

We summarize some applications of big bang nucleosythesis (BBN) and the cosmic microwave background (CMB) to constrain the first moments of the creation of matter in the universe. We review the basic elements of BBN and how it constraints…

Cosmology and Nongalactic Astrophysics · Physics 2018-05-23 Grant. J. Mathews , Mayukh Gangopadhyay , Nishanth Sasankan , Kiyotomo Ichiki , Toshitaka Kajino

It is clear that matter is dominant in the Universe compared to antimatter. We call this problem baryon asymmetry. The baryon asymmetry is experimentally determined by both cosmic microwave background and big bang nucleosynthesis…

High Energy Physics - Phenomenology · Physics 2022-05-18 Dong Woo Kang , Jongkuk Kim , Takaaki Nomura , Hiroshi Okada

Big Bang Nucleosynthesis (BBN) and the Cosmic Background Radiation (CBR) provide complementary probes of the early evolution of the Universe and of its particle content. Neutrinos play important roles in both cases, influencing the…

Astrophysics · Physics 2007-05-23 Gary Steigman

Fluctuations in the intensity and polarization of the cosmic microwave background (CMB) and the large-scale distribution of matter in the universe each contain clues about the nature of the earliest moments of time. The next generation of…

Since the B-mode polarization of the cosmic microwave background (CMB) was detected by the BICEP2 experiment and an unexpectedly large tensor-to-scalar ratio, $r=0.20^{+0.07}_{-0.05}$, was found, the base standard cosmology should at least…

Cosmology and Nongalactic Astrophysics · Physics 2014-07-22 Jing-Fei Zhang , Yun-He Li , Xin Zhang

Interest in non-standard recombination scenarios has been spurred by recent cosmic microwave background (CMB) results from BOOMERANG and MAXIMA, which show an unexpectedly low second acoustic peak, resulting in a best-fit baryon density…

Astrophysics · Physics 2009-10-31 Steen Hannestad , Robert J. Scherrer

We reanalyze the cosmological constraints on the existence of a net universal lepton asymmetry and neutrino degeneracy. We show that neutrinos can begin to decouple at higher temperatures than previous estimates due to several corrections…

Astrophysics · Physics 2007-05-23 M. Orito , T. Kajino , G. J. Mathews , R. N. Boyd
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