EDM constraints in supersymmetric theories

Physical Review D, 2000

We analyze the neutron electric dipole moment (EDM) in the Minimal Supersymmetric Model with explicit R-parity violating terms. The leading contribution to the EDM occurs at the 2-loop level and is dominated by the chromoelectric dipole moments of quarks, assuming there is no tree-level mixings between sleptons and Higgs bosons or between leptons and gauginos. Based on the experimental constraint on the neutron EDM, we set limits on the imaginary parts of complex couplings λ ′ ijk and λ ijk due to the virtual b-loop or τ -loop.

Physical Review D, 1994

It is well known that supersymmetry (SUSY) gives neutron and electron electric dipole moments (d n and d e) which are too large by about 10 3. If we assume a SUSY model cannot contain fine-tunings or large mass scales, then one must require that the SUSY breaking mechanism give real soft breaking parameters, in which case the minimal SUSY model has no CP violation other than from the CKM matrix (besides possible strong CP violating effects). We show that in non-minimal SUSY models, a moderate amount of CP violation can be induced through one loop corrections to the scalar potential, giving an effective phase of order 10 −3 , and thus implying d n and d e can be near their current experimental bounds naturally. This moderate amount of SUSY CP violation could also prove important for models of electroweak baryogenesis. We illustrate our results with a specific model.

Nuclear Physics B, 1994

CP violating effects in the Minimal Supersymmetric Standard Model (MSSM) can lead to excessively large contributions to the neutron EDM (d n). We write criteria which ensure that the low energy supergravity (SUGRA) parametrization of the MSSM does not require fine-tunings or large mass scales to evade the constraint from d n , and consider the implications on SUGRA theories. In particular, we show that in the Polonyi model, two of the mass scales are in general complex, meaning that model does not naturally avoid a large d n as is sometimes claimed.

Journal of High Energy Physics, 2008

We explore in detail the consequences of the CP-violating phases residing in the supersymmetric and soft SUSY breaking parameters in the approximation that family flavour mixings are ignored. We allow for non-universal boundary conditions and in such a consideration the model is described by twelve independent CP-violating phases and one angle which misaligns the vacuum expectation values (VEVs) of the Higgs scalars. We run two-loop renormalization group equations (RGEs), for all parameters involved, including phases, and we properly treat the minimization conditions using the one-loop effective potential with CPviolating phases included. We show that the two-loop running of phases may induce sizable effects for the electric dipole moments (EDMs) that are absent in the one-loop RGE analysis. Also important corrections to the EDMs are induced by the Higgs VEVs misalignment angle which are sizable in the large tan β region. Scanning the available parameter space we seek regions compatible with accelerator and cosmological data with emphasis on rapid neutralino annihilations through a Higgs resonance. It is shown that large CP-violating phases, as required in Baryogenesis scenarios, can be tuned to obtain agreement with WMAP3 cold dark matter constraints, EDMs and all available accelerator data, in extended regions of the parameter space which may be accessible to LHC.

Nuclear Physics B, 2003

We analyze the CP problem in the context of a supersymmetric extension of the standard model with universal strength of Yukawa couplings. A salient feature of these models is that the CP phases are constrained to be very small by the hierarchy of the quark masses and the pattern of CKM mixing angles. This leads to a small amount of CP violation from the usual KM mechanism and a significant contribution from supersymmetry is required. Due to the large generation mixing in some of the supersymmetric interactions, the electric dipole moments impose severe constraints on the parameter space, forcing the trilinear couplings to be factorizable in matrix form. We find that the LL mass insertions give the dominant gluino contribution to saturate ε K . The chargino contributions to ε ′ /ε are significant and can accommodate the experimental results. In this framework, the standard model gives a negligible contribution to the CP asymmetry in B-meson decay, a J/ψK S . However, due to supersymmetric contributions to B d −B d mixing, the recent large value of a J/ψK S can be accommodated.

2012

We find in theories with spontaneous P and CP violation that symmetries needed to set the tree level strong CP phase to zero can also set all non-zero tree level CP violating phases to the maximal value π/2 in the symmetry basis simultaneously explaining the smallness ofθ and the largeness of the CKM CP violating phase. In these models we find the one loop lower bound θ ≥ 10 −11 relevant for early discovery of neutron EDM dn ≥ 10 −27 ecm. The lower bound relaxes toθ ≥ 10 −13 or dn ≥ 10 −29 ecm for the case where the CP phases are non-maximal. Interestingly the spontaneous CP phase appears in the quark sector, not the Higgs sector, and is enabled by a heavy P symmetric vectorlike quark family with mass M. These results do not vanish in the decoupling limit of M H + 2 > M → ∞ (where M H + 2 is the mass of heavy Higgses at the parity breaking scale) and the age-old expectation that laws of nature (or its Lagrangian) are parity and matter-antimatter symmetric may be testable by the above predictions and EDM experiments, even if new physics occurs only at seesaw , GUT or Planck scales. There is also a region in parameter space with M H + 2 < M where the above bounds are dampened by the factor (M H + 2 /M) 2. By using flavour symmetries and texture arguments we also make predictions for the CKM phase that arises from the maximal phase on diagonalization to the physical basis. There are no axions predicted in this model.

Physical Review D, 2006

The possibility of cancelation between different contributions to d e , d n and d Hg has been reconsidered with special emphasis on the region that is phenomenologically interesting (intermediate values of tan β and sub-TeV sfermion masses). It is found that in the range favored by electroweak baryogenesis (i.e., |µ| ≃ M 1 or |µ| ≃ M 2), sin[θ µ + θ M 1 ] ∼ 1 can be compatible with the EDM bounds even for slepton masses below 500 GeV. Such large values of the phases promise a successful electroweak baryogenesis. The possibility of large CP-odd effects at linear collider has also been discussed.

Physics Letters B, 1990

The calculation of neutron EDM due to the exchange of neutral Higgs bosons is reconsidered. We find that, contrary to previous claims, both the scalar and the pseudoscalar Higgs nucleon couplings are not dominated by the heavy-quark contributions. The relevant pseudoscalar coupling is calculated by using the recent EMC data on the nucleon matrix element of the axial vector current; the scalar coupling incorporates the information contained in the nN sigma-term. The need for a proper treatment of the strange quark operators between the nucleon states is emphasized.

Physical Review D, 2001

The electron electric dipole moment (d e) and the muon magnetic moment anomaly (a µ) recently observed at BNL are analyzed within the framework of SUGRA models with CP violating phases at the GUT scale. It is seen analytically that even if d e were zero, there can be a large Bino mass phase (ranging from 0 to 2π) with a corresponding large B soft breaking mass phase (of size < ∼ 0.5 with sign fixed by the experimental sign of a µ). The dependence of the B phase on the other SUSY parameters, gaugino mass m 1/2 , tan β, A 0 , is examined. The lower bound of a µ determines the upper bound of m 1/2. It is shown analytically how the existence of a non-zero Bino phase reduces this upper bound (which would correspondingly lower the SUSY mass spectra). The experimental upper bound on d e determines the range of allowed phases, and the question of whether the current bound on d e requires any fine tuning is investigated. At the electroweak scale, the phases have to be specified to within a few percent. At the GUT scale, however, the B phase requires fine tuning below the 1% level over parts of the parameter space for low m 1/2 , and if the current experimental bound on d e were reduced by only a factor of 3−4, fine tuning below 1% would occur at both the electroweak and GUT scale over large regions of the parameter space. All accelerator constraints (m h > 114 GeV, b → sγ, etc.) and relic density constraints with all stau-neutralino co-annihilation processes are included in the analysis.

Physical Review D, 2010

We demonstrate that in effective theories arising from N = 1 fluxless compactifications of Mtheory on a G2 manifold with low energy supersymmetry, CP-violating phases do not appear in the soft-breaking Lagrangian except via the Yukawas. Such a mechanism may be present in other string compactifications as well; we describe properties sufficient for this to occur. CP violation is generated via the Yukawas since the soft trilinear matrices are generically not proportional to the Yukawa matrices. Within the framework considered, the estimated theoretical upper bounds for electric dipole moments (EDM) of the electron, neutron and mercury are all within the current experimental limits and could be probed in the near future.