The Efimov effect in lithium 6

We analyse the recent experiments investigating the low-energy physics of three lithium 6 atoms in three different internal states with resonant two-body scattering lengths. All observed features are qualitatively consistent with the expected Efimov effect, i.e. the effective universal three-body attraction that arises for large values of the scattering lengths. However, we find that a quantitative description at negative energy requires non-universal two- and three-body corrections due to presently unknown behaviour at short distance. An attempt to implement these corrections is made through energy-dependent parameters that are fitted to the experimental data. (C) 2010 Academie des sciences. Published by Elsevier Masson SAS. All rights reserved.