New constraints on short-range forces coupling mass to intrinsic spin

Phys Rev Lett. 2007 Feb 23;98(8):081101. doi: 10.1103/PhysRevLett.98.081101. Epub 2007 Feb 23.

Abstract

A new device that we refer to as the spherical superconducting torsion balance has been used to search for a new force coupling mass to intrinsic spin. Our experimental approach also employs a novel spin-source geometry that allows unprecedented sensitivity in the range 100 mum<lambda<5 mm. We place new limits on the dimensionless coupling constant of such an interaction of g_{p};{e}g_{s}<(-1.9+/-(1.3)_{stat}+/-(1.5)_{syst})x10;{-26} for lambda>10 mm at 1sigma confidence. At a range of 1 mm our most relaxed limit is g_{p};{e}g_{s}<1.5x10;{-24}.