Resolution to the SupersymmetricCPProblem with Large Soft Phases via D-Branes

Abstract

We examine the soft supersymmetry breaking parameters that result from various ways of embedding the Standard Model (SM) on D-branes within the Type I string picture, allowing the gaugino masses and µ to have large CP-violating phases. One embedding naturally provides the relations among soft parameters to satisfy the electron and neutron electric dipole moment constraints even with large phases, while with other embeddings large phases are not allowed. The string models provide some motivation for large phases in the soft breaking parameters. The results generally suggest how low energy data might teach us about Planck scale physics.

Gaugino CP phases and EDMs in the extended gauge mediation SUSY breaking

“…In the appendix we present an example for the realization of the required messenger superpotential. 1 In the case of the electron EDM the cancellation between the chargino and neutralino contributions have been shown to occur [9,10,11]. On the other hand, in the case of the neutron EDM it has been known that there are several types of cancellation , that is, the cancellation between the gluino and the chargino exchange diagrams and also the cancellation among the gluino exchange diagrams in themselves etc [9,15].…”

“…The other one is that the soft CP-phases are supposed to be of the order unity by assuming the soft scalar masses to take larger values than 1 TeV, which is considered to be unattractive from the view point of the weak scale supersymmetry. If we can have the third possibility in which the order one CP-phases and the superpartners with the masses of the order of 100 GeV can be consistent with the EDM constraints, it is very interesting and we can have a lot of interesting phenomenology [9,10,11,12,13]. In particular, if we consider the origin of the baryon number asymmetry in the universe, we may need new sources of CP violation.…”

“…On the other hand, in the case of the neutron EDM it has been known that there are several types of cancellation , that is, the cancellation between the gluino and the chargino exchange diagrams and also the cancellation among the gluino exchange diagrams in themselves etc [9,15]. The combined effect of these cancellations allows the possibility of the large soft CP-phases [9,10,11]. …”

“…In fact, there are interesting suggestions that the experimental constraints on the EDM can be satisfied due to the effective cancellation among various contributions to the EDM 1 as far as the CP-phases in the gaugino masses are non-universal even in the case where both the order one CP-phases and rather light superpartners exist. Unfortunately, the non-universal gaugino masses seems to be rather difficult to be realized in both the unified theory and the superstring as discussed in [11,16]. However, if we consider the GMSB such that some kind of discrete symmetry imposes the SU(3) triplet and SU(2) doublet messenger fields couple to the different singlet fields where the supersymmetry is broken due to the hidden sector dynamics, we can show that the non-universal phases in the gaugino masses appear naturally [17].…”

“…When we consider this third possibility, it is useful to note that the usual analyses of the EDM are based on the assumption of the universal gaugino masses as stressed in [11].…”