Laboratory for Particle Properties (Phi-lab)
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Short distance gravity

The force of gravity is confirmed to follow an inverse square law (ISL) famously known as “Newton’s Law of Universal Gravitation”. This law can be derived within general relativity in the nonrelativistic limit in a weak gravitational field. Its validity has been verified experimentally down to distances of less than 1 mm.

However, the nature of gravity at shorter ranges is very poorly constrained. Many alternative theories of gravity possess an additional component of the gravitational interactions which involve the exchange of massive quanta and therefore only extends to short ranges. Other theories which try to explain why gravity is so weak compared to the other interactions of Nature (“hierarchy” problem) also produce short-distance modifications to the ISL.

In our research we employ neutron scattering to search for such modifications to the ISL at the nm length scale. By making precise measurements of the q-dependence of the neutron-noble gas differential scattering cross section , we can place stringent limits on the upper bound of the strength of a new possible force of Nature which would cause a deviation from the ISL.