Probing additional dimensions in the universe with neutron experiments

Abstract

We carry out a simple analysis of (n + 3)-dimensional gravity in the context of recent work on 'large' supplementary dimensions and deduce a formula for the expected compactification radius for the n additional dimensions in the universe, as a function of the Planck and the electro-weak scales. We argue that the correspondingly modified gravitational force gives rise to effects that might be within the detection range of dedicated neutron experiments. A scattering analysis of the corresponding modified gravitational forces suggests that slow neutron scattering off atomic nuclei with null spin may provide an experimental test for these ideas.The study of gravity at short range has recently been the subject of numerous theoretical and experimental investigations, sparked by the proposal by Arkani-Hamed, Dimoupoulos, and Dvali (ADD) [1] that gravity may depart from Newton's inverse square law at scales which could be as large as a millimeter. Diverse experimental groups have built refined versions of torsion balance experiments and other ingenious designs to test gravity at submillimeter ranges [2]. On the theoretical front, hundreds of papers have been written, ranging from alternative formulations of the large extra-dimensions framework (LED) [3], to the study of astrophysical constraints and the expected experimental consequences in future high-energy collider experiments to black-hole production and the effect of LED on fundamental symmetries. But perhaps the most remarkable result to date is the fact that no known physical constraints have as yet falsified the LED theories. From the experimental point of view the new measurements have confirmed the validity of Newton's