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Centro de Astrofísica da Universidade do Porto

Early-universe constraints on a time-varying fine structure constant

P. P. Avelino, S. Esposito, G. Mangano, C. J. A. P. Martins, A. Melchiorri, G. Miele, O. Pisanti, G. Rocha, P. T. P. Viana

Abstract
Higher-dimensional theories have the remarkable feature of predicting a time (and hence redshift) dependence of the ``fundamental'' four dimensional constants on cosmological time scales. In this paper, we update the bounds on a possible variation of the fine structure constant α at the time of big bang nucleosynthesis (z~1010) and cosmic microwave background (CMB) (z~103). Using the recently released high-resolution CMB anisotropy data and the latest estimates of primordial abundances of 4He and D, we do not find evidence for a varying α at more than a one-sigma level at either epoch.

Physical Review D
Volume 64, Page 103505
November 2001

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Institute of Astrophysics and Space Sciences

Institute of Astrophysics and Space Sciences (IA) is a new but long anticipated research infrastructure with a national dimension. It embodies a bold but feasible vision for the development of Astronomy, Astrophysics and Space Sciences in Portugal, taking full advantage and fully realizing the potential created by the national membership of the European Space Agency (ESA) and the European Southern Observatory (ESO). IA resulted from the merging the two most prominent research units in the field in Portugal: the Centre for Astrophysics of the University of Porto (CAUP) and the Center for Astronomy and Astrophysics of the University of Lisbon (CAAUL). It currently hosts more than two-thirds of all active researchers working in Space Sciences in Portugal, and is responsible for an even greater fraction of the national productivity in international ISI journals in the area of Space Sciences. This is the scientific area with the highest relative impact factor (1.65 times above the international average) and the field with the highest average number of citations per article for Portugal.

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