172 research outputs found
Higgs Boson Masses in the MSSM with Heavy Majorana Neutrinos
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
We study the supersymmetric (SUSY) QCD radiative corrections, at the one-loop
level, to , 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 decay width approaches its Standard Model value at one loop, with the onset
of decoupling being delayed for large 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 , is
found in the SUSY-QCD corrections to the decay width
at one loop. In contrast, the SUSY-QCD corrections in the
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
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
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
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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