CEDM Constraints on Modified Sfermion Universality and Spontaneous CP Violation

• Published in: Progress of theoretical and experimental physics 2009-09, Vol.122 (3), p.659-671
• Main Authors: Ishiduki, Megumi, Kim, Sung-Gi, Maekawa, Nobuhiro, Sakurai, Kazuki
• Format: Article
• Language: English
• ISSN: 0033-068X; 2050-3911; 1347-4081
• DOI: 10.1143/PTP.122.659

We discuss the supersymmetric CP problem that arises when the sfermion soft mass universality is modified. We place the 3rd generation SU(5) 10-plet sfermion masses in the weak scale in view of the naturalness. The other sfermion masses are assumed to be universal and to be of order a TeV scale to weaken the flavor changing neutral current processes and electric dipole moment (EDM) constraints. However, this modification generically induces very large up quark chromo-EDM (CEDM) via the weak-scale stop loop. To suppress this CEDM, we propose a certain type of flavor structure where the parameters of the up-(s)quark sector are real, whereas those of the down-(s)quark and charged (s)lepton sectors are complex at the grand unified theory (GUT) scale. It is shown that, in this setup, up quark CEDM can be suppressed within the range where the current and future experiments have their sensitivity. We briefly illustrate the simple realization of these particular forms of the modified sfermion universality with real up-(s)quark sector by spontaneous CP violation in E 6 SUSY GUT with SU(2) flavor symmetry.