Constraints on new gravitylike forces in the nanometer range.

We report on a new constraint on gravitylike short-range forces, in which the interaction charge is mass, obtained by measuring the angular distribution of 5 Å neutrons scattering off atomic xenon gas. Around 10^{7} scattering events were collected at the 40 m small angle neutron scattering beam line located at the HANARO research reactor of the Korean Atomic Energy Research Institute. The extracted coupling strengths of new forces in the Yukawa-type parametrization are g[over ^]^{2}=(0.2±6.8±2.0)×10^{-15}  GeV^{-2} and g[over ^]^{2}=(-5.3±9.0_{-2.8}^{+2.7})×10^{-17}  GeV^{-2} for interaction ranges of 0.1 and 1.0 nm, respectively. These strengths correspond to 95% confidence level limits of g^{2}<(1.4±0.2)×10^{-14}  GeV^{-2} and g^{2}<(1.3±0.2)×10^{-16}  GeV^{-2}, improving the current limits for interaction ranges between 4 and 0.04 nm by a factor of up to 10.