The Pneumatology of Brevard S. Childs

Barr, David P.

doi:10.18130/v3cq2q

Cited by 6 publications

(15 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Since the gaugino phases are identically zero and the range of ϕ Ae is severely restricted by correlations between A and M at the string scale, the cancellations are insufficient in this particular scenario. Therefore, only a very small fraction of the ϕ µ − ϕ Ae parameter space leads to models allowed by the electron EDM, in direct analogy with the dilaton-dominated scenario in the perturbative heterotic models discussed in [18].…”

Section: B Resultsmentioning

confidence: 99%

“…For the sake of simplicity, we assume the string scale and the GUT scale coincide, and that the gauge couplings unify at this scale. Thus, in the first model we consider with SU(3) and U(1) Y arising from the same brane sector, the boundary conditions (17) and (18) are implemented at the GUT scale, and the parameters are subsequently evolved down to the electroweak scale. The sparticle masses and the CPviolating phases depend on the free parameters m 3/2 , θ, Θ i , i = 1, 2, 3, which are related by Θ 2 1 +Θ 2 2 +Θ 2 3 = 1, as well as the two phases α 1 and α 2 .…”

Section: B Resultsmentioning

confidence: 99%

“…It is therefore unlikely that sufficient cancellations will occur in this limit except at exceptional points in the parameter space depending on the (model-dependent) solution to the µ problem, and thus the traditional solutions to the supersymmetric CP problem of either small O(10 −2 ) phases or heavy squark masses must be invoked to avoid electric dipole moments for the electron and the neutron which violate the experimental bounds. The analysis of the EDM constraints within the dilaton-dominated scenario has recently been presented in [18]; their results demonstrate explicitly that large phases are disallowed over the majority of the parameter space.…”

Section: A Theoretical Frameworkmentioning

confidence: 99%

“…However, in the limit in which only the overall modulus T contributes to SUSY breaking, the gaugino masses are universal in this scenario. Hence, significant CP-violating phases in the soft terms consistent with the phenomenological bounds are disallowed over the majority of parameter space (the situation is analogous to that of the dilaton-dominated limit of perturbative heterotic orbifold models studied in [18]).…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Superstring theory andCP-violating phases: Can they be related?

et al. 2000

View full text Add to dashboard Cite

We investigate the possibility of large CP-violating phases in the soft breaking terms derived in superstring models. The bounds on the electric dipole moments (EDM's) of the electron and neutron are satisfied through cancellations occuring because of the structure of the string models. Three general classes of four-dimensional string models are considered: (i) orbifold compactifications of perturbative heterotic string theory, (ii) scenarios based on Hořava-Witten theory, and (iii) Type I string models (Type IIB orientifolds). Nonuniversal phases of the gaugino mass parameters greatly facilitate the necessary cancellations among the various contributions to the EDM's; in the overall modulus limit, the gaugino masses are universal at tree level in both the perturbative heterotic models and the Hořava-Witten scenarios, which severely restricts the allowed regions of parameter space. Nonuniversal gaugino masses do arise at one-loop in the heterotic orbifold models, providing for corners of parameter space with O(1) phases consistent with the phenomenological bounds. However, there is a possibility of nonuniversal gaugino masses at tree level in the Type I models, depending on the details of the embedding of the SM into the D-brane sectors. We find that in a minimal model with a particular embedding of the Standard Model gauge group into two D-brane sectors, viable large phase solutions can be obtained over a wide range of parameter space.

show abstract

Section: B Resultsmentioning

confidence: 99%

Section: B Resultsmentioning

confidence: 99%

Section: A Theoretical Frameworkmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Superstring theory andCP-violating phases: Can they be related?

et al. 2000

View full text Add to dashboard Cite

show abstract

“…It was shown that in the universal case, as in the minimal supergravity models, the prediction of the asymmetry is less than 2%, since in this case the electric dipole moments (EDM) of the electron and neutron constrain the SUSY CP-violating phases to be very small [2,3]. Furthermore, it is also known that in this case, one can not get any sizeable SUSY contribution to the CP-violating observables, ε and ε ′ /ε [4][5][6][7]. The impact of flavour structure in the non-degenerate A-terms, which is expected in string inspired models, has been studied [6][7][8].…”

mentioning

confidence: 99%

Flavor-Dependent Supersymmetric Phases andCPAsymmetry inB→XsγDecays

Bailin

Khalil

2001

Phys. Rev. Lett.

View full text Add to dashboard Cite

We study the direct CP asymmetry in B → Xsγ decay in SUSY models with non-universal Aterms. We show that the flavour-dependent phases of the A-terms, unlike the flavour-independent ones, can give rise too large contribution to the CP asymmetry while respecting the experimental bounds on the branching ratio of B → Xsγ decay and the electric dipole moments of the electron and neutron. The CP asymmetry of this decay is predicted to be much larger than the standard model prediction in a wide region of the parameter space. In particular, it can be of order 10 − 15% which can be accessible at B factories.PACS numbers:12.60. Jv, 11.30.Er, Direct CP asymmetry in the inclusive radiative decay B → X s γ is measured by the quantityThe Standard Model (SM) prediction for this asymmetry is very small, less than 1%. Thus, the observation of sizeable asymmetry in the decay B → X s γ would be a clean signal of new physics.The most recent result reported by CLEO collaboration for the CP asummetry in these decays is [1]and it is expected that the measurements of A b→sγ CP will be improved in the next few years at the B-factories.Supersymmetric predictions for A b→sγ CP are strongly dependent on the flavour structure of the soft breaking terms. It was shown that in the universal case, as in the minimal supergravity models, the prediction of the asymmetry is less than 2%, since in this case the electric dipole moments (EDM) of the electron and neutron constrain the SUSY CP-violating phases to be very small [2,3]. Furthermore, it is also known that in this case, one can not get any sizeable SUSY contribution to the CP-violating observables, ε and ε ′ /ε [4][5][6][7]. The impact of flavour structure in the non-degenerate A-terms, which is expected in string inspired models, has been studied [6][7][8]. In these works, it was emphasized that the flavour-dependent SUSY CP-violating phases are not essentially constrained by the EDMs and can lead to large contributions to the observed CP-violating phenomena in the kaon system and, in particular, to the direct CP violation measured by ε ′ /ε.In this letter, we explore the effect of these large flavour-dependent phases on inducing a direct CP violation in B → X s γ decay. We will show that the values of the asymmetry A b→sγ CP in this class of models are much larger than the SM prediction in a wide region of the parameter space allowed by experiments, namely the EDM experimental limits and the bounds on the branching ratio of B → X s γ . The enhancement of A b→sγ CP is due to the important contributions from gluino-mediated diagrams, in this scenario, in addition to the usual chargino and charged Higgs contributions.The effective Hamiltonian for b → sγ decay is given bywhere Q i (µ b ) and C i (µ b ) represent an operator for the ∆B = 1 transition and its Wilson coefficient, respectively, evaluated at the renormalization scale µ b ≃ O(m b ). The relevant operators for b → sγ decay are given byThe expression for the asymmetry A b→sγ CP , corrected to next-to-leading order is given by [9]where...

show abstract

Asymmetric Dark Matter: Theories, signatures, and constraints

2014

View full text Add to dashboard Cite

We review theories of Asymmetric Dark Matter (ADM), their cosmological implications and detection. While there are many models of ADM in the literature, our review of existing models will center on highlighting the few common features and important mechanisms for generation and transfer of the matter-anti-matter asymmetry between dark and visible sectors. We also survey ADM hidden sectors, the calculation of the relic abundance for ADM, and how the DM asymmetry may be erased at late times through oscillations. We consider cosmological constraints on ADM from the cosmic microwave background, neutron stars, the Sun, and brown and white dwarves. Lastly, we review indirect and direct detection methods for ADM, collider signatures, and constraints.

show abstract

The Pneumatology of Brevard S. Childs

Cited by 6 publications

References 2 publications

Superstring theory andCP-violating phases: Can they be related?

Superstring theory andCP-violating phases: Can they be related?

Flavor-Dependent Supersymmetric Phases andCPAsymmetry inB→XsγDecays

Asymmetric Dark Matter: Theories, signatures, and constraints

Contact Info

Product

Resources

About