No sign of symmetrons
(Vienna University of Technology) One of the candidates for 'dark energy' is the symmetron field. At the TU Vienna researchers have developed an experiment capable of measuring extremely small forces with the help of neutrons. The measurements were taken at the Institut Laue-Langevin. They could have provided pointers to the mysterious symmetrons, but the particles didn't show up. This excludes the possibility of symmetrons in a broad parameter range. 'Dark energy' is going to have to be explained differently.