17 research outputs found
Radiative Electroweak Breaking with Pseudogoldstone Higgs Doublets
We consider a realistic example of supersymmetric grand unification based on
in which the electroweak (EW) higgs
doublets are `light' as a consequence of the `pseudogoldstone' mechanism. We
discuss radiative EW breaking in this model, exploring in particular the
`small' (order unity) and `large' regions by
studying the variations of , where
are the well known MSSM parameters evaluated at the GUT scale.
For sufficiently close to unity the quantity can be of order
unity, but the converse is not always true.Comment: 18 pages plain LaTeX (to be run twice) and 11 figures available
separately from uuencoded file
Supersymmetric Models With Tan(beta) Close to Unity
Within the framework of supersymmetric grand unification, estimates of the
quark mass based on the asymptotic relation single out
the region with close to unity, particularly if . We explore the radiative breaking of the
electroweak symmetry and the associated sparticle and higgs spectroscopy in
models with . The lightest scalar higgs
is expected to have a mass below , while the remaining four higgs
masses exceed . The lower bounds on some of the sparticle masses are
within the range of LEP 200.Comment: 13 pages in plain LaTeX, BA-94-02, 15 figures (available on request
Zeroing In On the Top Quark, LSP and Scalar Higgs Masses
We estimate the top quark, lightest sparticle (LSP) and scalar higgs masses
within a supersymmetric grand unified framework in which and the electroweak symmetry is radiatively broken. The requirement
that the calculated quark mass lie close to its measured value, together
with the cosmological constraint , fixes the top quark
mass to be . The LSP (of bino purity
has mass . In the scalar
higgs sector the CP-odd scalar mass . With
, as suggested by the decay , we find and .Comment: 14 pages in plain LaTeX, BA-93-25, PRL-TH-93/
Yukawa coupling unification and non-universal gaugino mediation of supersymmetry breaking
The requirement of Yukawa coupling unification highly constrains the SUSY
parameter space. In several SUSY breaking scenarios it is hard to reconcile
Yukawa coupling unification with experimental constraints from B(b->s gamma)
and the muon anomalous magnetic moment a_mu. We show that b-tau or even t-b-tau
Yukawa unification can be satisfied simultaneously with b->s gamma and a_mu in
the non-universal gaugino mediation scenario. Non-universal gaugino masses
naturally appear in higher dimensional grand unified models in which gauge
symmetry is broken by orbifold compactification. Relations between SUSY
contributions to fermion masses, b->s gamma and a_mu which are typical for
models with universal gaugino masses are relaxed. Consequently, these
phenomenological constraints can be satisfied simultaneously with a relatively
light SUSY spectrum, compared to models with universal gaugino masses.Comment: 20 pages, 8 figures. References added. A copy of the paper with
better resolution figures can be found at
http://www.hep.fsu.edu/~balazs/Physics/Papers/2003
Predictions for Higgs and SUSY spectra from SO(10) Yukawa Unification with mu > 0
We use Yukawa unification to constrain SUSY parameter space. We
find a narrow region survives for (suggested by \bsgam and the
anomalous magnetic moment of the muon) with , , \gev and \gev. Demanding Yukawa unification thus makes definite predictions for
Higgs and sparticle masses.Comment: 10 pages, 3 figures, revised version to be published in PR
Sparticle mass spectra from SU(5) SUSY GUT models with Yukawa coupling unification
Supersymmetric grand unified models based on the gauge group SU(5) often
require in addition to gauge coupling unification, the unification of b-quark
and -lepton Yukawa couplings. We examine SU(5) SUSY GUT parameter space
under the condition of Yukawa coupling unification using 2-loop MSSM
RGEs including full 1-loop threshold effects. The Yukawa-unified solutions
break down into two classes. Solutions with low tan\beta ~3-11 are
characterized by gluino mass ~1-4 TeV and squark mass ~1-5 TeV. Many of these
solutions would be beyond LHC reach, although they contain a light Higgs scalar
with mass <123 GeV and so may be excluded should the LHC Higgs hint persist.
The second class of solutions occurs at large tan\beta ~35-60, and are a subset
of unified solutions. Constraining only unification to ~5%
favors a rather light gluino with mass ~0.5-2 TeV, which should ultimately be
accessible to LHC searches. While our unified solutions can be
consistent with a picture of neutralino-only cold dark matter, invoking
additional moduli or Peccei-Quinn superfields can allow for all of our
Yukawa-unified solutions to be consistent with the measured dark matter
abundance.Comment: 19 pages, 5 figures, 1 table, PDFLate
SUSY GUT Model Building
I discuss an evolution of SUSY GUT model building, starting with the
construction of 4d GUTs, to orbifold GUTs and finally to orbifold GUTs within
the heterotic string. This evolution is an attempt to obtain realistic string
models, perhaps relevant for the LHC. This review is in memory of the sudden
loss of Julius Wess, a leader in the field, who will be sorely missed.Comment: 24 pages, 14 figures, lectures given at PiTP 2008, Institute for
Advanced Study, Princeton, to be published in the European Physical Journal
The Bottom Mass Prediction in Supersymmetric Grand Unification; Uncertainties and Constraints
Grand unified theories often predict unification of Yukawa couplings (e.g.,
), and thus certain relations among fermion masses. The
latter can distinguish these from models that predict only coupling constant
unification. The implications of Yukawa couplings of the heavy-family in the
supersymmetric extension of the standard model (when embedded in a GUT) are
discussed. In particular, uncertainties associated with and ,
threshold corrections at the low-scale, and threshold and
nonrenormalizable-operator corrections associated with a grand-unified sector
at the high-scale are parametrized and estimated. The implication of these and
of the correlation between and the prediction for are
discussed. Constraints on the range in such models and an upper
bound on the -quark pole mass are given and are shown to be affected by the
correlation. Constraints on the low-scale thresholds are
found to be weakened by uncertainties associated with the high-scale.Comment: 23 pages + 7 figures (figures are available upon request), LaTex +
RevTex 3.0, UPR-0556
On Supersymmetric b-tau Unification, Gauge Unification, and Fixed Points
The equality assumption of the b and tau Yukawa couplings at the
grand-unification scale can strongly constrain the allowed parameter space of
supersymmetric models. We examine the constraints in the case that there is a
discrepancy > 10% in the gauge coupling unification assumption (which
necessarily implies large perturbations at the grand scale). The constraints
are shown to diminish in that case [most significantly so if alpha_{s}(M_{Z})
\approx 0.11]. In particular, the requirement that the t Yukawa coupling,
h_{t}, is near its quasi-fixed point may not be necessary. We discuss the
colored-triplet threshold as a simple example of a source for the
discrepancies, and comment on its possible implications. In addition, we point
out that supersymmetric (as well as unification-scale) threshold corrections to
h_{t} shift the fixed-point curve in the m_{t} - \tan\beta plane. The
implications for the prediction of the Higgs boson mass are briefly discussed.Comment: 17 pages + 7 postscript figures (packaged as a .uu file), LaTex +
RevTex