Search for new gravity-like short range interactions in the submicron range by means of neutron-nanoparticle scatteringⅠ*

The large-extra-dimension models are the candidate of the theoretical solution for so-called hierarchy problem in the energy scale of elementary particles. Some of those models suggest deviation of the gravitational force from the inverse-square law in the range shorter than a few mm due to the effect of a new interaction induced by the graviton traveling through the extra dimensions. We previously performed an experimental search for new gravity-like interactions in the submicron range by measuring small-angle neutron scattering with noble gas atoms at the Japan Proton Accelerator Research Complex (J-PARC) [1], and we are now improving the sensitivity of the measurement by using a target made of nanoparticles which are about six orders of magnitude heavier than noble gas atoms. In this new method the sensitivity to new interactions is expected to increase thanks to the coherent neutron scattering. In principle, the background from the nuclear scattering is also enhanced by the coherent scattering. To suppress the coherent nuclear scattering, we will employ nanoparticles made of the elements with positive coherent scattering length and the one with negative one such as vanadium and titanium [2]. Currently, we are developing the production method of nanoparticles of vanadium-nickel alloy and pure vanadium using the RF thermal plasma method. In this presentation, the current status of nanoparticle development and the results of SANS measurements will be presented.