Phenomenological implications of light stop and higgsinos

Brignole, Andrea; Feruglio, Ferruccio; Zwirner, Fabio

doi:10.1007/bf02907030

Cited by 22 publications

(57 citation statements)

References 20 publications

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“…For the purposes of this study, the important feature remains that these individual moduli will contribute to gaugino masses only at one-loop. Therefore, the number of parameters increases substantially; in addition to the need to define extra Goldstino angles (as is done in [11] and will be required in the Type I models discussed below), there will be [12,13] a δ GS , ǫ, etc. for each modulus field involved in the supersymmetry breaking, the details of which will depend on the particular orbifold model under consideration.…”

Section: B Resultsmentioning

confidence: 99%

“…In the analysis of [10,11], the primary assumption is that supersymmetry is broken by a combination of the dilaton field S and the moduli T m present in generic four-dimensional string models. These fields have a vanishing (perturbative) scalar potential and gravitationally suppressed interactions with the fields of the observable sector, and thus are natural candidates to play a role in the breakdown of supersymmetry.…”

Section: A Theoretical Frameworkmentioning

confidence: 99%

“…The soft supersymmetry breaking terms obtained when the dilaton and moduli fields are responsible for the breakdown of supersymmetry can be determined using the parameterization of the F -component VEV's (following [11,21]):…”

Section: A Theoretical Frameworkmentioning

confidence: 99%

“…Following [10][11][12], we first consider models derived from weakly coupled heterotic string theory in orbifold compactifications [13], and focus on the case in which S and one "overall modulus" field T participate in the supersymmetry breaking. In these models, the dilaton F term leads to universal gaugino masses at tree-level; however, the modulus field T does provide a nonuniversal contribution at one-loop order (although loop-suppressed).…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2000

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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.

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Section: B Resultsmentioning

confidence: 99%

Section: A Theoretical Frameworkmentioning

confidence: 99%

Section: A Theoretical Frameworkmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

et al. 2000

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“…Hence one can ask the following question: can the CMSSM present some novelties in CP-violating phenomena when we consider χ + -t loops with lightt, χ + and/or H + ? Several analyses in the literature tackle the above question or, to be more precise, the more general problem of the effect of lightt and χ + on FCNC processes [7][8][9]. A first important observation concerns the relative sign of the W + -t loop with respect to the χ + -t and H + -t contributions.…”

Section: Cp Violation In Susymentioning

confidence: 99%

CP violation in SUSY

Masiero

Vives

2001

Nuclear Physics B - Proceedings Supplements

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Supersymmetry exhibts new sources of CP violation. We discuss the implications of these new contributions to CP violation both in the K and B physics. We show that CP violation puts severe constraints on low energy SUSY, but it represents also a promising ground to look for signals of new physics. CP VIOLATION IN SUSYCP violation has major potentialities to exhibit manifestations of new physics beyond the standard model. Indeed, it is quite a general feature that new physics possesses new CP violating phases in addition to the Cabibbo-KobayashiMaskawa (CKM) phase (δ CKM ) or, even in those cases where this does not occur, δ CKM shows up in interactions of the new particles, hence with potential departures from the SM expectations. Moreover, although the SM is able to account for the observed CP violation in the kaon system, we cannot say that we have tested so far the SM predictions for CP violation. The detection of CP violation in B physics will constitute a crucial test of the standard CKM picture within the SM. Again, on general grounds, we expect new physics to provide departures from the SM CKM scenario for CP violation in B physics. A final remark on reasons that make us optimistic in having new physics playing a major role in CP violation concerns the matter-antimatter asymmetry in the universe. Starting from a baryonantibaryon symmetric universe, the SM is unable to account for the observed baryon asymmetry. The presence of new CP-violating contributions when one goes beyond the SM looks crucial to produce an efficient mechanism for the generation of a satisfactory ∆B asymmetry.The above considerations apply well to the new physics represented by low-energy supersymmetric extensions of the SM. Indeed, as we will see * Present address Dep Física Teòrica, U de València, Spain below, supersymmetry introduces CP violating phases in addition to δ CKM and, even if one envisages particular situations where such extraphases vanish, the phase δ CKM itself leads to new CP-violating contributions in processes where SUSY particles are exchanged. CP violation in B decays has all potentialities to exhibit departures from the SM CKM picture in low-energy SUSY extensions, although, as we will discuss, the detectability of such deviations strongly depends on the regions of the SUSY parameter space under consideration.In any MSSM, at least two new "genuine" SUSY CP-violating phases are present. They originate from the SUSY parameters µ, M , A and B. The first of these parameters is the dimensionful coefficient of the H u H d term of the superpotential. The remaining three parameters are present in the sector that softly breaks the N=1 global SUSY. M denotes the common value of the gaugino masses, A is the trilinear scalar coupling, while B denotes the bilinear scalar coupling. In our notation, all these three parameters are dimensionful. The simplest way to see which combinations of the phases of these four parameters are physical [1] is to notice that for vanishing values of µ, M , A and B the theory possesses two addit...

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Upper Limits on Sparticle Masses from WMAP Dark Matter Constraints with Modular Invariant Soft Breaking

Chattopadhyay

Nath

Dark Matter in Astro- And Particle Physics

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An analysis of dark matter within the framework of modular invariant soft breaking is given. In such scenarios inclusion of the radiative electroweak symmetry breaking constraint determines tan β which leads to a more constrained analysis. It is shown that for µ positive for this constrained system the WMAP data leads to upper limits on sparticle masses that lie within reach of the LHC with also the possibility that some sparticles may be accessible at RUNII of the Tevatron.

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Phenomenological implications of light stop and higgsinos

Abstract: We examine the phenomenological implications of lightt R and higgsinos in the Minimal Supersymmetric Standard Model, assuming tan 2 β < m t /m b and heavyt L and gauginos. In this simplified setting, we study the contributions to ∆m, and their interplay.

Cited by 22 publications

References 20 publications

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

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

CP violation in SUSY

Upper Limits on Sparticle Masses from WMAP Dark Matter Constraints with Modular Invariant Soft Breaking

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