%0 Journal Article
%T Search for Millicharged Particles Using Optically Levitated Microspheres
%A David C. Moore
%A Alexander D. Rider
%A Giorgio Gratta
%J Physics
%D 2014
%I arXiv
%R 10.1103/PhysRevLett.113.251801
%X We report results from a search for stable particles with charge > $10^{-5}$ e in bulk matter using levitated dielectric microspheres in high vacuum. No evidence for such particles was found in a total sample of 1.4 ng, providing an upper limit on the abundance per nucleon of 2.5 x $10^{-14}$ at the 95% confidence level for the material tested. These results provide the first direct search for single particles with charge < 0.1 e bound in macroscopic quantities of matter and demonstrate the ability to perform sensitive force measurements using optically levitated microspheres in vacuum.
%U http://arxiv.org/abs/1408.4396v2