2003/09/08 by G. Rocha, R. Trotta, Roberto Trotta +6 · 86 citations
Physics and Astronomy · #Astronomy #Astrophysics #CMB cold spot #Cosmic background radiation #Cosmic microwave background #Cosmic variance #Cosmology and Gravitation Theories #Dark Matter and Cosmic Phenomena #Particle physics theoretical and experimental studies #Physics #Planck #Quantum mechanics #Spectral index #Spectral line #astro-ph
paper · pdf · doi:10.1111/j.1365-2966.2004.07832.x
published in Monthly Notices of the Royal Astronomical Society 352(1), 20-38 (Oxford University Press) · 29 pages, 11 figures, 15 tables, submitted to MNRAS. Higher resolution figures available at http://www.mrao.cam.ac.uk/~graca/alpha
arxiv created 2003/09/08 · openalex publication_date 2004/07/01 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We present a detailed analysis of present and future cosmic microwave background (CMB) constraints of the value of the fine-structure constant, α. We carry out a more detailed analysis of the WMAP first-year data, deriving state-of-the-art constraints on α and discussing various other issues, such as the possible hints for the running of the spectral index. We find, at 95 per cent confidence level, that 0.95 < αdec/α0 < 1.02. Setting dnS/d ln k= 0 yields 0.94 < αdec/α0 < 1.01 as previously reported. We find that a lower value of αdec/α0 makes a value of dnS/d ln k= 0 more compatible with the data. We also perform a thorough Fisher matrix analysis (including both temperature and polarization, as well as α and the optical depth τ), in order to estimate how future CMB experiments will be able to constrain α and other cosmological parameters. We find that Planck data alone can constrain τ with an accuracy of the order 4 per cent and that this constraint can be as small as 1.7 per cent for an ideal cosmic variance limited (CVL) experiment. Constraints on α are of the order of 0.3 per cent for Planck and can in principle be as small as 0.1 per cent using CMB data alone: tighter constraints will require further (non-CMB) priors.