Constraints on anomalous spin-spin interactions from spin-exchange collisions

A comparison between existing measurements and calculated cross sections for spin exchange between alkali-metal atoms and noble gases (specifically sodium and helium) is used to constrain anomalous spin-dependent forces between nuclei at the atomic scale (similar to 10(-8) cm). Combined with existing stringent limits on anomalous short-range, spin-dependent couplings of the proton, the dimensionless coupling constant for an axial vector interaction of the neutron arising from exchange of a boson of mass less than or similar to 100 eV is constrained to be g(A)(n)/root 4 pi(h) over barc < 2 x 10(-3). Constraints are established for a velocity-and spin-dependent interaction alpha (I . v)(K . v), where I and K are the nuclear spins of He and Na, respectively, and v is the relative velocity of the atoms. Constraints on torsion gravity are also considered.