Vanishing contribution to quark electric dipole moment in the 2HD model with CKM CP violation - art. no. 073004

In the standard model (SM) of electroweak interactions, CP noninvariance ar ises from the nonzero phase in the CKM matrix. Its contribution to the quar k electric dipole moment (EDM) vanishes surprisingly at two loop order. Thi s makes the quark EDM extremely small in the SM. In this paper, we consider the two Higgs doublet extension of the SM and assume that CP noninvariance is still encoded in the CKM matrix. We calculate the charged Higgs boson c ontribution to the quark EDM which naively should be of order e G(F)(2)<(de lta)over bar>(4 pi)(-4) m(u(d))m(t)(2)m(b)(2)m(H)(-2) for the up (down) qua rk with possible enhancement factors of tan(2) beta. Here <(delta)over bar> is the rephasing invariant of CP violation. However, contrary to the above naive expectation, we find that the charged Higgs boson contribution vanis hes strictly at two loop order. We show explicitly how this comes about and explain how it is related to the general form of Yukawa couplings in a spo ntaneously broken gauge theory. [S0556-2821(99)01517-9].