Electric Dipole Moment of the Neutron from 2+1 Flavor Lattice QCD

We compute the electric dipole moment d(n) of the neutron from a fully dynamical simulation of lattice QCD with 2 + 1 flavors of clover fermions and nonvanishing theta term. The latter is rotated into a pseudoscalar density in the fermionic action using the axial anomaly. To make the action real, the vacuum angle theta is taken to be purely imaginary. The physical value of d(n) is obtained by analytic continuation. We find d(n) = - 3.9(2)(9) x 10-(16) theta e cm, which, when combined with the experimental limit on d(n), leads to the upper bound vertical bar theta vertical bar less than or similar to 7.4 x 10(-11).