Short-Range Gravity Experiment Newton-IVh at millimeter scale

A large extra dimensional model predicts deviations from the Newtonian gravity at short distances below millimeters. Present NEWTON project at Rikkyo University aims an experimental test to Newton's inverse-square law at the millimeter scale. In order to examine the gravitational force at short range scale around millimeter, we have developed a new apparatus NEWTON-IVh using a torsion pendulum with a pico-precision displacement sensor using digital image analysis system, which was originally developed for a high energy collider experiment at RHIC. We determine the~~~gravitational force by measuring the twisting angle of the torsion pendulum when the gravitational sources are moved around the torsion pendulum.~~In this presentation, the development status and the results of the NEWTON-IVh experiment will be reported.