158 research outputs found
FeynHiggsFast: a program for a fast calculation of masses and mixing angles in the Higgs Sector of the MSSM
FeynHiggsFast is a Fortran code for the calculation of the masses and the
mixing angle of the neutral CP-even Higgs bosons in the MSSM up to two-loop
order. It is based on a compact analytical approximation formula of the
complete diagrammatic one-loop and the dominant two-loop contributions. At the
one-loop level a leading logarithmic result is used, taking into account all
sectors of the MSSM. At the two-loop level at O(alpha alpha_s) the leading
logarithmic and non-logarithmic contributions are taken into account. The
approximation formula is valid for arbitrary choices of the parameters in the
Higgs sector of the model. Comparing its quality to the full diagrammatic
result, we find agreement better than 2 GeV for most parts of the MSSM
parameter space.Comment: 10 pages, 6 figures. Extended version of the contribution to the
Report of the HIGGS working group for the Workshop ``Physics at TeV
Colliders'' Les Houches, France, June 199
FeynHiggs: a program for the calculation of the masses of the neutral CP-even Higgs bosons in the MSSM
FeynHiggs is a Fortran code for the calculation of the masses of the neutral
CP-even Higgs bosons in the MSSM up to two-loop order. It is based on the
complete diagrammatic on-shell results at the one-loop level, the leading
diagrammatic two-loop QCD contributions and further improvements taking into
account leading electroweak two-loop and leading higher-order QCD corrections.
The Higgs-boson masses are calculated as functions of the MSSM parameters for
general mixing in the scalar top sector and arbitrary choices of the parameters
in the Higgs sector of the model.Comment: 16 page
Higher-order results in the Higgs sector of the MSSM
We analyze the impact of the recent Feynman-diagrammatic (FD) two-loop
results for the mass of the lightest CP-even Higgs boson in the MSSM on the
theoretical upper bound for mh as a function of tan(beta). The results are
compared with previous results obtained by renormalization group (RG) methods.
The incorporation of dominant FD two-loop corrections into the decay width
\Gamma(h -> f \bar f) is also discussed.Comment: 4 pages, 2 figures, presented by G. Weiglein at the ``International
Europhysics Conference on High Energy Physics'', Tampere, July 199
Neutral MSSM Higgs-boson production at e+e- colliders in the Feynman-diagrammatic approach
We calculate the cross sections for the neutral Higgs-boson production at
e+e- colliders in the Minimal Supersymmetric Standard Model (MSSM) using the
Feynman-diagrammatic approach and the on-shell renormalization scheme. We
incorporate the Higgs-boson propagator corrections, evaluated up to two-loop
order, into the prediction of the cross sections for the Higgs-boson production
mechanism e+e- -> hZ, hA. The propagator corrections consist of the full
one-loop contribution, including the effects of non-vanishing external
momentum, and at the two-loop level of the dominant corrections of O(alpha
alpha_s) and further sub-dominant contributions. The results are supplemented
with the complete set of one-loop vertex and box corrections. The effects of
the two-loop propagator corrections are investigated in detail. We briefly
discuss also the effect of the box contributions for high . We
compare our results with the case where only the corrections to the effective
mixing angle, evaluated within the renormalization-group-improved one-loop
Effective Potential approach, are taken into account. We find agreement better
than 10% for LEP2 energies and deviations larger than 20% for = 500
GeV.Comment: 26 pages, 9 figure
Z Pole Observables in the MSSM
We present the currently most accurate prediction of Z pole observables such
as sin^2 theta_eff, Gamma_Z, R_b, R_l, and sigma^0_had in the Minimal
Supersymmetric Standard Model (MSSM). We take into account the complete
one-loop results including the full complex phase dependence, all available
MSSM two-loop corrections as well as the full SM results. We furthermore
include higher-order corrections in the MSSM Higgs boson sector, entering via
virtual Higgs boson contributions. For Gamma(Z -> neutralino{1} neutralino{1})
we present a full one-loop calculation. We analyse the impact of the different
sectors of the MSSM with particular emphasis on the effects of the complex
phases. The predictions for the Z boson observables and M_W are compared with
the current experimental values. Furthermore we provide an estimate of the
remaining higher-order uncertainties in the prediction of sin^2 theta_eff.Comment: 53 pages, 20 figures, journal versio
Two-loop electroweak contributions to
A review is given on the quantum correction in the -- mass
correlation at the electroweak two-loop level, as derived from the calculation
of the muon lifetime in the Standard Model. Exact results for and
the -mass prediction including corrections with
fermion loops are presented and compared with previous results of a
next-to-leading order expansion in the top-quark mass.Comment: 14 pages, including 4 figures. Presented at the 5th International
Symposium on Radiative Corrections, (RADCOR-2000), Carmel CA, USA, 11-15
September 200
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