Constraints on short-range spin-dependent interactions from scalar spin-spin coupling in deuterated molecular hydrogen.

A comparison between existing nuclear magnetic resonance measurements and calculations of the scalar spin-spin interaction (J coupling) in deuterated molecular hydrogen yields stringent constraints on anomalous spin-dependent potentials between nucleons at the atomic scale (∼ 1 Å). The dimensionless coupling constant g(P)(p)g(P)(N)/4 π associated with the exchange of pseudoscalar (axionlike) bosons between nucleons is constrained to be less than 3.6 × 10(-7) for boson masses in the range of 5 keV, representing improvement by a factor of 100 over previous constraints. The dimensionless coupling constant g(A)(p)g(A)(N)/4 π associated with the exchange of an axial-vector boson between nucleons is constrained to be g(A)(p)g(A)(N)/4 π<1.3 × 10(-19) for bosons of mass ≲ 1000 eV, improving constraints at this distance scale by a factor of 100 for proton-proton couplings and more than 8 orders of magnitude for neutron-proton couplings.