The Electric Dipole Moment of the Muon in a Two Higgs Doublet Model

Abstract

The electric dipole moment of the muon ($d_{\mu }$) is evaluated in a two Higgs doublet model with a softly broken discrete symmetry. The leading contributions from both one loop and two loop diagrams are considered. For $\tan \beta \equiv |v_2|/|v_1|$ close to one, contributions from two loop diagrams involving the $t$ quark and the $W$ boson dominate; while for $\tan \beta \text{agt}10$, contributions from two loop diagrams involving the $b$ quark and the $\tau$ lepton are dominant. In these two regions, $d_{\mu }\approx (m_{\mu }/m_e)d_e$. For $8\text{agt}\tan \beta \text{agt}4$, significant cancellation occurs among the contributions from two loop diagrams and the one loop contribution dominates for $\tan \beta \sim 7$. For $\tan \beta \text{agt}15$, the calculated $d_{\mu }$ can be close to the reach of a recently proposed experiment at the Brookhaven National Laboratory.

Comments: 16 pages, REVTeX, 7 Postscript Figures, To be published in Physical Review D