Anomalous Neutron Scattering on Supercritical Xenon

The xenon1g experiment searches for new fundamental forces, "fifth-forces", at nanometer scales by exploiting critical phenomena in a few grams of supercritical Xe-136.

Using small-angle neutron scattering (SANS), the experiment aims to detect Yukawa-type deviations from Newtonian gravity in the 10 nanometer range, probing the sub-micrometer regime predicted by diverse theoretical frameworks including light scalar fields from string theory (dilatons and moduli), dark sector forces mediated by additional gauge symmetries, and axion-like particles. The approach leverages the tunable correlation lengths and diverging compressibility near xenon liquid-gas critical point: allowing for coherent enhancement of scattering signals from hypothetical new interactions. Experimental measurements conducted at SSRL (SLAC) with SAXS have validated the method, and we are planning for our first SANS data run in 2026.