4-8 August 2015
America/Detroit timezone

Bound on the variation in the fine structure constant implied by Oklo data

5 Aug 2015, 14:00
18m
Michigan (Michigan League)

Michigan

Michigan League

Cosmology and Dark Energy Experiment AstroParticle, Cosmology, Dark Matter Searches, and CMB

Speaker

Ms Leila HAMDAN (Kuwait University)

Description

Dynamical models of dark energy can imply that the fine structure constant $\alpha$ varies over cosmological time scales. Data on shifts in resonance energies $E_r$ from the Oklo natural fission reactor have been used to place restrictive bounds on the change in $\alpha$ over the last 1.8 billion years. We review the uncertainties in these analyses, focusing on corrections to the standard estimate of $k_\alpha\!=\!\alpha\,dE_r/d\alpha$ due to Damour and Dyson. Guided, in part, by the best practice for assessing systematic errors in theoretical estimates spelt out by Dobaczewski et al. [in J. Phys. G: Nucl. Part. Phys. 41, 074001 (2014)], we compute these corrections in a variety of models tuned to reproduce existing nuclear data. Although the net correction is uncertain to within a factor of 2 or 3, it constitutes at most no more than 25\% of the Damour-Dyson estimate of $k_\alpha$. Making similar allowances for the uncertainties in the modeling of the operation of the Oklo reactors, we conclude that the relative change in $\alpha$ since the Oklo reactors were last active (redshift $z\simeq 0.14$) is less than $\sim 10$ parts per billion. To illustrate the utility of this low-$z$ bound, we consider its implications for the string-inspired runaway dilaton model of Damour, Piazza and Veneziano.
Oral or Poster Presentation Poster

Primary author

Ms Leila HAMDAN (Kuwait University)

Co-author

Prof. Edward David DAVIS (Kuwait University)

Presentation Materials