165 research outputs found
Supersymmetry breaking in M-theory and quantization rules
We analyze in detail supersymmetry breaking by compactification of the fifth
dimension in M-theory in the compactification pattern and
find that a superpotential is generated for the complex fields coming from
hypermultiplets, namely the dilaton and the complex structure moduli. Using
general arguments it is shown that these fields are always stabilized such that
they don't contribute to supersymmetry breaking, which is completely saturated
by the K\"ahler moduli coming from vector multiplets.
It is shown that this mechanism is the strong-coupling analog of the
Rohm-Witten quantization of the antisymmetric tensor field strength of string
theories. The effect of a gaugino condensate on one of the boundaries is also
considered.Comment: 16 pages, LaTex, no figure
Three-form multiplet and Inflation
Most successful models of inflation in supergravity have a shift symmetry for
the inflaton and contain a stabilizer field coupled to the inflaton in a
particular way. We argue that the natural interpretation of the stabilizer,
from the viewpoint of the shift symmetry, is a three-form multiplet. Its
coupling to the inflaton is uniquely determined by the shift symmetry and the
invariance under three-form gauge transformations and has a natural string
theory interpretation.Comment: 15 pages, references adde
General soft terms from Supergravity including D-terms
We derive general expressions for soft terms in supergravity where D-terms
contribute significantly to the supersymmetry breaking. Such D-terms can
produce large splitting between scalar and fermionic partners in the spectrum.
By requiring that supersymmetry breaking sets the cosmological constant to
zero, we then parameterize the soft terms when D-terms dominate over F-terms or
are comparable to them. We present an application of our results to the split
supersymmetry scenario and briefly address the issue of moduli stabilisation.Comment: 6 Pages, no figures. To appear in proceedings of the XXXXth
Rencontres de Moriond "Electroweak Interactions and Unified Theories", La
Thuile, Italy, March 5-12, 2005; V2 Typos in eq.(9) corrected and other
improvement
Low Scale Supersymmetry Breaking and its LHC Signatures
We study the most general extension of the MSSM Lagrangian that includes
scenarios in which supersymmetry is spontaneously broken at a low scale f. The
spurion that parametrizes supersymmetry breaking in the MSSM is promoted to a
dynamical superfield involving the goldstino, with (and without) its scalar
superpartner, the sgoldstino. The low energy effective Lagrangian is written as
an expansion in terms of m_{SUSY}/sqrt{f}, where m_{SUSY} is the induced
supersymmetry breaking scale, and contains, in addition to the usual MSSM
Lagrangian with the soft terms, couplings involving the component fields of the
goldstino superfield and the MSSM fields. This Lagrangian can provide
significant corrections to the usual couplings in the Standard Model and the
MSSM. We study how these new corrections affect the Higgs couplings to gauge
bosons and fermions, and how LHC bounds can be used in order to constrain f. We
also discuss that, from the effective field theory point of view, the couplings
of the goldstino interactions are not determined by any symmetry, and their
usual simple relation to the soft terms is corrected by higher-dimensional
operators.Comment: 46 pages, 3 figure
The Case for an EeV Gravitino
We consider the possibility that supersymmetry is broken above the
inflationary mass scale and that the only "low" energy remnant of supersymmetry
is the gravitino with mass of order the EeV scale. The gravitino in this class
of models becomes a candidate for the dark matter of the Universe. To avoid the
over-production of gravitinos from the decays of the next-to-lightest
supersymmetric particle we argue that the supersymmetric spectrum must lie
above the inflationary mass scale ( GeV). Since , we expect
EeV. Cosmological constraints then predict a relatively
large reheating temperature between and GeV.Comment: 6 pages, 1 figure. Dedicated to the memory of Pierre Binetru
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