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Like a Rolling Constant

Paolo Molaro
University of Trieste, Italy

Do the fundamental constants of Nature actually vary over cosmological time and distance scales? This question goes into the heart of cosmology, physics and particle physics. Several theories beyond the Standard Model of Particle Physics allow for varying of fundamental physical constants as well as  dark energy if due to quintessence.  
Astronomical observations and in particular of absorption lines recorded in the spectra of distant QSOs allow extremely accurate study of  atomic structure and can effectively probe in time the variability of the dimensionless constants such as the fine structure constant and proton-to-electron mass ratio. The current status of the research will be  critically reviewed trying to understand the controversial results obtained. New results coming from radio observations of dense pre-stellar molecular clouds in the Milky Way will be also presented.  
These show an intriguing signal that, when taken at face value, implies spatial variations of the mp/me ratio of about 30 ppb (parts-per-billion). However, the conflict with atomic clock experiments requires non universal coupling with a sort of chameleon-type  scalar fields. The prospects of the ESO Large Program just taking off and of the ESPRESSO and CODEX  projects will be outlined. These  will make possible  significant improvements and opening an entirely new field of research in case of positive results.

2010 September 01, 13:30

Centro de AstrofÝsica da Universidade do Porto (Auditorium)
Rua das Estrelas, 4150-762 Porto

Instituto de Astrof├şsica e Ci├¬ncias do Espa├žo Universidade do Porto Faculdade de Ciências da Universidade de Lisboa Funda├ž├úo para a Ci├¬ncia e a Tecnologia
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