3,529 research outputs found

    CP violation in models with TeV-scale SUSY breaking

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    We estimate contributions of the goldstino supermultiplet to the electric dipole moment (EDM) in the case that the SUSY breaking scale \Lambda_S is of order the TeV scale. We found that such contributions can saturate the experimental bound if \Lambda_S is close to the soft mass scale. We also discuss EDM in the gaugino mediated scenario on the warped geometry as an example of models with the TeV-scale SUSY breaking.Comment: 12 pages, 4 figure

    Orbifold-induced μ\mu term and electroweak symmetry breaking

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    It is known that a Higgs μ\mu term can be naturally generated through the K\"ahler potential in orbifold string models in which one of the three compactified complex planes has order two. In this class of models explicit expressions for both the μ\mu parameter and the soft SUSY-breaking parameters can be obtained under the assumption that the goldstino is an arbitrary linear combination of the fermionic partners of the dilaton SS and all the moduli Ti,UiT_i,U_i. We apply this picture to the MSSM and explore the consistency of the obtained boundary conditions with radiative gauge symmetry breaking. We find that consistency with the measured value of the top-quark mass can only be achieved if the goldstino has a negligible dilatino component and relevant components along the T3,U3T_3,U_3 moduli associated to the order-two complex plane.Comment: 9 pages, LaTeX fil

    One-loop Kahler potential in non-renormalizable theories

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    We consider a general d=4 N=1 globally supersymmetric lagrangian involving chiral and vector superfields, with arbitrary superpotential, Kahler potential and gauge kinetic function. We compute perturbative quantum corrections by employing a component field approach that respects supersymmetry and background gauge invariance. In particular, we obtain the full one-loop correction to the Kahler potential in supersymmetric Landau gauge. Two derivations of this result are described. The non-renormalization of the superpotential and the quadratic correction to the Fayet-Iliopoulos terms are further checks of our computations.Comment: 17 pages, LaTe

    Four-fermion interactions and sgoldstino masses in models with a superlight gravitino

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    We discuss the role of the effective interactions among four matter fermions in supersymmetric models with a very light gravitino. We show that, from a field-theoretical viewpoint, no model-independent bound on the gravitino mass can be derived from such interactions. Making use of a naturalness criterion, however, we are able to derive some interesting but not very stringent bounds, complementary to those obtained from the direct production of supersymmetric particles. We also show that, generically, masses for the spin-0 partners of the goldstino (sgoldstinos) of the order of the gravitino mass and much smaller than squark and slepton masses do not obey a naturalness criterion.Comment: 9 A4 pages, 1 figure, LATEX, uses axodraw.sty. Version to be published in Phys. Lett. B: an important spin-off on sgoldstino masses adde

    The supersymmetric Higgs boson with flavoured A-terms

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    We consider a supersymmetric scenario with large flavour violating A-terms in the stop/scharm sector and study their impact on the Higgs mass, the electroweak rho parameter and the effective Higgs couplings to gluons, photons and charm quarks. For each observable we present explicit analytical expressions which exhibit the relevant parametric dependences, both in the general case and in specific limits. We find significant effects and comment on phenomenological implications for the LHC and future colliders.Comment: 21 pages, 6 figures; v2: minor changes, references added (journal version

    Sgoldstino events in top decays at LHC

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    We study top-quark decays in models with light sgoldstinos. The off-diagonal entries in the squark mass matrices can lead to FCNC top two-body decays into sgoldstinos and u(c) quarks. We compute the rates for these decays and discuss the corresponding signatures that could manifest the presence of sgoldstinos in top decays at LHC. We expect that a supersymmetry breaking scale F\sqrt{F} up to a scale of order 10 TeV could be probed through this process, for a maximal squark mixing with the third generation. Justified by our preliminary analysis, a thorough study of the corresponding signal versus background and systematics in the LHC environment would be most welcome, in order to accurately assess the potential of this promising process in determining F\sqrt{F}.Comment: Standard LaTeX, 11 pages, 4 figures, one reference adde

    Superlight gravitinos in electron-photon collisions

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    Motivated by recent studies of supersymmetry in higher-dimensional spaces, we discuss the experimental signatures of a superlight gravitino, mass < 0.001 eV. We concentrate on the process (e- gamma -> selectronR gravitino) as a probe of supersymmetry, where a single heavy superpartner and a superlight gravitino are produced. The fact that there is only one heavy superpartner in the final state in this process would require a lower center-of-mass energy for on-shell production compared to conventional pair production. For instance, for a 500 GeV machine, we find that a positive signal will be found if the supersymmetry breaking scale is less than about 2 TeV. If no positive signal is found, this process puts a bound on the supersymmetry breaking scale.Comment: 8 pages Added 2 terms to eqn(3) for easy reference and other minor changes to improve clarit

    The decay h0A0A0h^0 \to A^0A^0: a complete 1-loop calculation in the MSSM

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    In the minimal supersymmetric standard model the decay h0A0A0h^0 \to A^0A^0 of the light neutral scalar h0h^0 is kinematically allowed for low values of tanβ\tan\beta when radiative corrections to the neutral Higgs masses are taken into account. The width of this decay mode is revisited on the basis of a complete 1-loop diagrammatic calculation. We give the analytical expressions and numerical results and compare them with the corresponding ones from the simpler and compact approximations of the effective potential method and the renormalization group approach.Comment: 25 pages, LaTex, 10 figures included. Complete ps-file also available via WWW at http://itpaxp1.physik.uni-karlsruhe.de/prep/prep.htm

    Radiative corrections to the decay H==>hh in the Minimal Supersymmetric Standard Model

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    We set up a suitable renormalization programme for the one-loop computation of the decay rate Gamma(H==>hh) in the Minimal Supersymmetric extension of the Standard Model. We then perform an explicit diagrammatic calculation, including the full contributions from top, bottom, stop and sbottom loops. We find that, for tan(beta) close to 1, and m_H greater than or approximately equal to 2 m_t, the results can significantly differ from those previously obtained in the effective potential approach. However, the latter method remains a good approximation in the region of parameter space which is most relevant for H searches at large hadron colliders.Comment: 11 A4-pages, 3 figures not included, CERN-TH.6603/9

    Lepton Flavour Violating Decays of Supersymmetric Higgs Bosons

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    We compute the lepton flavour violating couplings of Higgs bosons in the Minimal Supersymmetric Standard Model, and show that they can induce the decays (h,H,A) --> mu tau at non-negligible rates, for large tan(beta) and sizeable smuon-stau mixing. We also discuss the prospects for detecting such decays at LHC and other colliders, as well as the correlation with other flavour violating processes, such as tau --> mu gamma and tau --> 3 mu.Comment: 13 LaTeX pages, 2 postscript figures, uses epsfig and axodra
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