Searches for possible T-odd and P-odd short range interactions using polarized nuclei

Various theories predict the possible existence of T-odd and P-odd short-range forces between spin-$1/2$ fermions, proportional to $\mathbf{S} \cdot \mathbf{r}$ where $\mathbf{S}$ is the fermion spin and $\mathbf{r}$ is the separation between particles. We use ensembles of polarized nuclei and an unpolarized mass to search for such a force over sub-mm ranges. We established an improved upper bound on the product $g_s g_p^n$ of the scalar coupling to particles in the unpolarized mass and the pseudo-scalar coupling of polarized neutrons for force ranges from $10^{-4}$ to $10^{-2}$ m, corresponding to a mass range of 2 $\cdot$ 10$^{-3}$ to 2 $\cdot$ 10$^{-5}$ eV for the exchange boson.