3,529 research outputs found

### CP violation in models with TeV-scale SUSY breaking

We estimate contributions of the goldstino supermultiplet to the electric
dipole moment (EDM) in the case that the SUSY breaking scale \Lambda_S is of
order the TeV scale. We found that such contributions can saturate the
experimental bound if \Lambda_S is close to the soft mass scale. We also
discuss EDM in the gaugino mediated scenario on the warped geometry as an
example of models with the TeV-scale SUSY breaking.Comment: 12 pages, 4 figure

### Orbifold-induced $\mu$ term and electroweak symmetry breaking

It is known that a Higgs $\mu$ term can be naturally generated through the
K\"ahler potential in orbifold string models in which one of the three
compactified complex planes has order two. In this class of models explicit
expressions for both the $\mu$ parameter and the soft SUSY-breaking parameters
can be obtained under the assumption that the goldstino is an arbitrary linear
combination of the fermionic partners of the dilaton $S$ and all the moduli
$T_i,U_i$. We apply this picture to the MSSM and explore the consistency of the
obtained boundary conditions with radiative gauge symmetry breaking. We find
that consistency with the measured value of the top-quark mass can only be
achieved if the goldstino has a negligible dilatino component and relevant
components along the $T_3,U_3$ moduli associated to the order-two complex
plane.Comment: 9 pages, LaTeX fil

### One-loop Kahler potential in non-renormalizable theories

We consider a general d=4 N=1 globally supersymmetric lagrangian involving
chiral and vector superfields, with arbitrary superpotential, Kahler potential
and gauge kinetic function. We compute perturbative quantum corrections by
employing a component field approach that respects supersymmetry and background
gauge invariance. In particular, we obtain the full one-loop correction to the
Kahler potential in supersymmetric Landau gauge. Two derivations of this result
are described. The non-renormalization of the superpotential and the quadratic
correction to the Fayet-Iliopoulos terms are further checks of our
computations.Comment: 17 pages, LaTe

### Four-fermion interactions and sgoldstino masses in models with a superlight gravitino

We discuss the role of the effective interactions among four matter fermions
in supersymmetric models with a very light gravitino. We show that, from a
field-theoretical viewpoint, no model-independent bound on the gravitino mass
can be derived from such interactions. Making use of a naturalness criterion,
however, we are able to derive some interesting but not very stringent bounds,
complementary to those obtained from the direct production of supersymmetric
particles. We also show that, generically, masses for the spin-0 partners of
the goldstino (sgoldstinos) of the order of the gravitino mass and much smaller
than squark and slepton masses do not obey a naturalness criterion.Comment: 9 A4 pages, 1 figure, LATEX, uses axodraw.sty. Version to be
published in Phys. Lett. B: an important spin-off on sgoldstino masses adde

### The supersymmetric Higgs boson with flavoured A-terms

We consider a supersymmetric scenario with large flavour violating A-terms in
the stop/scharm sector and study their impact on the Higgs mass, the
electroweak rho parameter and the effective Higgs couplings to gluons, photons
and charm quarks. For each observable we present explicit analytical
expressions which exhibit the relevant parametric dependences, both in the
general case and in specific limits. We find significant effects and comment on
phenomenological implications for the LHC and future colliders.Comment: 21 pages, 6 figures; v2: minor changes, references added (journal
version

### Sgoldstino events in top decays at LHC

We study top-quark decays in models with light sgoldstinos. The off-diagonal
entries in the squark mass matrices can lead to FCNC top two-body decays into
sgoldstinos and u(c) quarks. We compute the rates for these decays and discuss
the corresponding signatures that could manifest the presence of sgoldstinos in
top decays at LHC. We expect that a supersymmetry breaking scale $\sqrt{F}$ up
to a scale of order 10 TeV could be probed through this process, for a maximal
squark mixing with the third generation. Justified by our preliminary analysis,
a thorough study of the corresponding signal versus background and systematics
in the LHC environment would be most welcome, in order to accurately assess the
potential of this promising process in determining $\sqrt{F}$.Comment: Standard LaTeX, 11 pages, 4 figures, one reference adde

### Superlight gravitinos in electron-photon collisions

Motivated by recent studies of supersymmetry in higher-dimensional spaces, we
discuss the experimental signatures of a superlight gravitino, mass < 0.001 eV.
We concentrate on the process (e- gamma -> selectronR gravitino) as a probe of
supersymmetry, where a single heavy superpartner and a superlight gravitino are
produced. The fact that there is only one heavy superpartner in the final state
in this process would require a lower center-of-mass energy for on-shell
production compared to conventional pair production. For instance, for a 500
GeV machine, we find that a positive signal will be found if the supersymmetry
breaking scale is less than about 2 TeV. If no positive signal is found, this
process puts a bound on the supersymmetry breaking scale.Comment: 8 pages Added 2 terms to eqn(3) for easy reference and other minor
changes to improve clarit

### The decay $h^0 \to A^0A^0$: a complete 1-loop calculation in the MSSM

In the minimal supersymmetric standard model the decay $h^0 \to A^0A^0$ of
the light neutral scalar $h^0$ is kinematically allowed for low values of
$\tan\beta$ when radiative corrections to the neutral Higgs masses are taken
into account. The width of this decay mode is revisited on the basis of a
complete 1-loop diagrammatic calculation. We give the analytical expressions
and numerical results and compare them with the corresponding ones from the
simpler and compact approximations of the effective potential method and the
renormalization group approach.Comment: 25 pages, LaTex, 10 figures included. Complete ps-file also available
via WWW at http://itpaxp1.physik.uni-karlsruhe.de/prep/prep.htm

### Radiative corrections to the decay H==>hh in the Minimal Supersymmetric Standard Model

We set up a suitable renormalization programme for the one-loop computation
of the decay rate Gamma(H==>hh) in the Minimal Supersymmetric extension of the
Standard Model. We then perform an explicit diagrammatic calculation, including
the full contributions from top, bottom, stop and sbottom loops. We find that,
for tan(beta) close to 1, and m_H greater than or approximately equal to 2 m_t,
the results can significantly differ from those previously obtained in the
effective potential approach. However, the latter method remains a good
approximation in the region of parameter space which is most relevant for H
searches at large hadron colliders.Comment: 11 A4-pages, 3 figures not included, CERN-TH.6603/9

### Lepton Flavour Violating Decays of Supersymmetric Higgs Bosons

We compute the lepton flavour violating couplings of Higgs bosons in the
Minimal Supersymmetric Standard Model, and show that they can induce the decays
(h,H,A) --> mu tau at non-negligible rates, for large tan(beta) and sizeable
smuon-stau mixing. We also discuss the prospects for detecting such decays at
LHC and other colliders, as well as the correlation with other flavour
violating processes, such as tau --> mu gamma and tau --> 3 mu.Comment: 13 LaTeX pages, 2 postscript figures, uses epsfig and axodra

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