UC Berkeley

We present PandaX-II constraints on candidate WIMP-nucleon effective interactions involving the nucleon or WIMP spin, including, in addition to standard axial spin-dependent (SD) scattering, various couplings among vector and axial currents, magnetic and electric dipole moments, and tensor interactions. The data set corresponding to a total exposure of 54-ton-days is reanalyzed to determine constraints as a function of the WIMP mass and isospin coupling. We obtain WIMP-nucleon cross section bounds of 1.6×10 −41 cm 2 and 9.0×10 −42 cm 2 (90% c.l.) for neutron-only SD and tensor coupling, respectively, for a mass M WIMP ∼40GeV/c 2 . The SD limits are the best currently available for M WIMP >40GeV/c 2 . We show that PandaX-II has reached a sensitivity sufficient to probe a variety of other candidate spin-dependent interactions at the weak scale.