3,675 research outputs found
Doubly Charged Higgsino Pair Production and Decays in e+e- Collisions
In supersymmetric grand unified theories, light higgsino multiplets generally
exist in addition to the familiar chargino/neutralino multiplets of the minimal
supersymmetric extension of the Standard Model. The new multiplets may include
doubly charged states and . We
study the properties and the production channels of these novel higgsinos in
and collisions, and investigate how their properties
can be analyzed experimentally.Comment: LATEX, 25 pages, ps figures include
The Higgs Sector of the Next-to-Minimal Supersymmetric Standard Model
The Higgs boson spectrum of the Next-to-Minimal Supersymmetric Standard Model
is examined. The model includes a singlet Higgs field S in addition to the two
Higgs doublets of the minimal extension. `Natural' values of the parameters of
the model are motivated by their renormalization group running and the vacuum
stability. The qualitative features of the Higgs boson masses are dependent on
how strongly the Peccei-Quinn U(1) symmetry of the model is broken, measured by
the self-coupling of the singlet field in the superpotential. We explore the
Higgs boson masses and their couplings to gauge bosons for various
representative scenarios.Comment: 32 pages with 12 figures; references and parameters updated; a few
minor comments adde
The Reconstruction of Supersymmetric Theories at High Energy Scales
The reconstruction of fundamental parameters in supersymmetric theories
requires the evolution to high scales, where the characteristic regularities in
mechanisms of supersymmetry breaking become manifest. We have studied a set of
representative examples in this context: minimal supergravity and a left--right
symmetric extension; gauge mediated supersymmetry breaking; and superstring
effective field theories. Through the evolution of the parameters from the
electroweak scale the regularities in different scenarios at the high scales
can be unravelled if precision analyses of the supersymmetric particle sector
at e+ e- linear colliders are combined with analyses at the LHC.Comment: 36 pages, latex, 6 figure
Production of Neutral Higgs-Boson Pairs at LHC
The reconstruction of the Higgs potential in the Standard Model or
supersymmetric theories demands the measurement of the trilinear Higgs
couplings. These couplings affect the multiple production of Higgs bosons at
high energy colliders. We present a systematic overview of the cross sections
for the production of pairs of (light) neutral Higgs bosons at the LHC. The
analysis is carried out for the Standard Model and its minimal supersymmetric
extension.Comment: Latex, 11 pages, uses feynmp.sty [included]. The complete paper,
including figures, is also available via anonymous ftp at
ftp://ttpux2.physik.uni-karlsruhe.de/ttp99/ttp99-17/ or via www at
http://www-ttp.physik.uni-karlsruhe.de/Preprints
The Reconstruction of Trilinear Higgs Couplings
To establish the Higgs mechanism {\it sui generis} experimentally, the Higgs
self-interaction potential must be reconstructed. This task requires the
measurement of the trilinear and quadrilinear self-couplings, as predicted in
the Standard Model or in supersymmetric theories. The couplings can be probed
in multiple Higgs production at high-luminosity e+e- linear colliders. We
present the theoretical analysis for the production of neutral Higgs-boson
pairs in the relevant channels of double Higgs-strahlung and associated
multiple Higgs production.Comment: 20 pages, Proceedings, "Physics with a High-Luminosity e+e- Linear
Collider", DESY/ECFA LC Workshop, DESY 99-123
Testing Higgs Self-couplings at e^+e^- Linear Colliders
To establish the Higgs mechanism sui generis experimentally, the self-energy
potential of the Higgs field must be reconstructed. This task requires the
measurement of the trilinear and quadrilinear self-couplings, as predicted, for
instance, in the Standard Model or in supersymmetric theories. The couplings
can be probed in multiple Higgs production at high-luminosity e^+e^- linear
colliders. Complementing earlier studies to develop a coherent picture of the
trilinear couplings, we have analyzed the production of pairs of neutral Higgs
bosons in all relevant channels of double Higgs-strahlung, associated multiple
Higgs production and WW/ZZ fusion to Higgs pairs.Comment: The complete paper, including figures, is also available via
anonymous ftp at ftp://ttpux2.physik.uni-karlsruhe.de/ttp99/ttp99-02/ or via
www at http://www-ttp.physik.uni-karlsruhe.de/cgi-bin/webmaster/preprints
Squark and Gluino Production at Hadron Colliders
We have determined the theoretical predictions for the cross-sections of
squark and gluino production at \ppb and colliders (Tevatron and LHC) in
next-to-leading order of supersymmetric QCD. By reducing the dependence on the
renormalization/factorization scale considerably, the theoretically predicted
values for the cross-sections are much more stable if these higher-order
corrections are implemented. If squarks and gluinos are discovered, this
improved stability translates into a reduced error on the masses, as extracted
experimentally from the size of the production cross-sections. The
cross-sections increase significantly if the next-to-leading order corrections
are included at a renormalization/factorization scale near the average mass of
the produced massive particles. This rise results in improved lower bounds on
squark and gluino masses. By contrast, the shape of the transverse-momentum and
rapidity distributions remains nearly unchanged when the next-to-leading order
corrections are included.Comment: 60 pages, Latex2e, 24 figures (uses epsfig.sty
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