Electric dipole moment of the neutron from a flavor changing Higgs-boson

Abstract

I consider neutron electric dipole moment contributions induced by flavor changing Standard Model Higgs boson couplings to quarks. Such couplings might stem from non-renormalizable SU(2)_L times U(1)_Y invariant Lagrange terms of dimension six, containing a product of three Higgs doublets. We extend previous one loop analysis to two loops. The divergent loops, due to non-renormalisabillity, are parametrized in terms of an ultraviolet cut-off Lambda . I also consider QCD corrections. Using the current experimental bound on the neutron electric dipole moment, then for cut offs from one to seven TeV, I find a constraint of order 10^{-3} for the imaginary part of the product of the Higgs flavor changing coupling for (d rightarrow b)-transition and the CKM element V_{td}. Assuming that the previous bound of the absolute value of the Higgs flavor changing coupling for (d rightarrow b)-transition obtained from B_d - bar{B_d}-mixing is saturated, the experimental bound on the neutron electric dipole moment would be reached for the bare result, if the cut off were extended up to about ca 20 TeV. However, QCD corrections suppress this result by a factor of order ten, and keep the nEDM below the experimental bound.