The Neutron Electric Dipole Moment and CP-violating Couplings in the   Supersymmetric Standard Model without R-parity
  We analyze the neutron electric dipole moment (EDM) in the Minimal Supersymmetric Model with explicit R-parity violating terms. The leading contribution to the EDM occurs at the 2-loop level and is dominated by the chromoelectric dipole moments of quarks, assuming there is no tree-level mixings between sleptons and Higgs bosons or between leptons and gauginos. Based on the experimental constraint on the neutron EDM, we set limits on the imaginary parts of complex couplings ${\lambda'}_{ijk}$ and ${\lambda}_{ijk}$ due to the virtual b-loop or tau-loop. 
Darwin Chang, We-Fu Chang, Mariana Frank, Wai-Yee Keung