170 research outputs found

    Higgs Boson Masses in the MSSM with Heavy Majorana Neutrinos

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    We present a full diagrammatic computation of the one-loop corrections from the neutrino/sneutrino sector to the renormalized neutral CP-even Higgs boson self-energies and the lightest Higgs boson mass, Mh, within the context of the so-called MSSM-seesaw scenario. This consists of the Minimal Supersymmetric Standard Model with the addition of massive right handed Majorana neutrinos and their supersymmetric partners, and where the seesaw mechanism is used for the lightest neutrino mass generation. We explore the dependence on all the parameters involved, with particular emphasis in the role played by the heavy Majorana scale. We restrict ourselves to the case of one generation of neutrinos/sneutrinos. For the numerical part of the study, we consider a very wide range of values for all the parameters involved. We find sizeable corrections to Mh, which are negative in the region where the Majorana scale is large (10^{13}-10^{15} GeV) and the lightest neutrino mass is within a range inspired by data (0.1-1 eV). For some regions of the MSSM-seesaw parameter space, the corrections to Mh are substantially larger than the anticipated Large Hadron Collider precision.Comment: Latex, 50 pages, 15 figures, 6 tables. Discussion improved. Comments and some new approximate formulae have been added. Published version on JHE

    Decoupling Properties of MSSM particles in Higgs and Top Decays

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    We study the supersymmetric (SUSY) QCD radiative corrections, at the one-loop level, to h0h^0, H±H^{\pm} and t quark decays, in the context of the Minimal Supersymmetric Standard Model (MSSM) and in the decoupling limit. The decoupling behaviour of the various MSSM sectors is analyzed in some special cases, where some or all of the SUSY mass parameters become large as compared to the electroweak scale. We show that in the decoupling limit of both large SUSY mass parameters and large CP-odd Higgs mass, the Γ(h0bbˉ)\Gamma (h^0\to b \bar b) decay width approaches its Standard Model value at one loop, with the onset of decoupling being delayed for large tanβ\tan\beta values. However, this decoupling does not occur if just the SUSY mass parameters are taken large. A similar interesting non-decoupling behaviour, also enhanced by tanβ\tan\beta, is found in the SUSY-QCD corrections to the Γ(H+tbˉ)\Gamma (H^+\to t \bar b) decay width at one loop. In contrast, the SUSY-QCD corrections in the Γ(tW+b)\Gamma (t\to W^+ b) decay width do decouple and this decoupling is fast.Comment: 19 pages, 10 figures. Invited talk presented by M.J.Herrero at the 5th International Symposium on Radiative Corrections (RADCOR 2000) Carmel CA, USA, 11-15 September, 200

    The SM as the Quantum Low Energy Effective Theory of the MSSM

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    In the framework of the Minimal Supersymmetric Standard Model we compute the one-loop effective action for the electroweak bosons obtained after integrating out the different sleptons, squarks, neutralinos and charginos, and present the result in terms of the physical sparticle masses. In addition we study the asymptotic behaviour of the two, three and four point Green's functions with external electroweak bosons in the limit where the physical sparticle masses are very large in comparison with the electroweak scale. We find that in this limit all the effects produced by the supersymmetric particles can be, either absorbed in the Standard Model parameters and gauge bosons wave functions, or else they are supressed by inverse powers of the supersymmetric particle masses. This work, therefore, completes the proof of decoupling of the heavy supersymmetric particles from the standard ones in the electroweak bosons effective action and in the sense of the Appelquist-Carazzone Theorem that we started in a previous work. From the point of view of effective field theories this work can be seen as a (partial) proof that the SM can be obtained indeed from the MSSM as the quantum low energy effective theory of this latter when the SUSY spectra is much heavier than the electroweak scale.Comment: 46 pages, LaTeX + 1 postscript figure included. The figure has been replaced. The body of the paper has not change

    Aeronautical facilities catalogue. Volume 2: Airbreathing propulsion and flight simulators

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    Volume two of the facilities catalogue deals with Airbreathing Propulsion and Flight Simulation Facilities. Data pertinent to managers and engineers are presented. Each facility is described on a data sheet that shows the facility's technical parameters on a chart and more detailed information in narratives. Facilities judged comparable in testing capability are noted and grouped together. Several comprehensive cross-indexes and charts are included

    Aeronautical Facilities Catalogue. Volume 1: Wind Tunnels

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    Domestic and foreign wind tunnel facilities are enumerated and their technical parameters are described. Data pertinent to managers and engineers are presented. Facilities judged comparable in testing capability are noted and grouped together. Several comprehensive cross-indexes and charts are included
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