5,643 research outputs found

### Low energy supersymmetry from R-symmetries

In a generic setting of Wess-Zumino models, we prove that the existence of a
supersymmetric vacuum with a vanishing superpotential can be a consequence of a
continuous or discrete R-symmetry when invariant fields are not less than
fields transforming in the same way as the superpotential under the R-symmetry.
The realization in string theory is discussed. We show that a rich landscape of
low energy supersymmetric vacua can be found in the Type IIB flux
compactification setup ready for the KKLT construction of de Sitter vacua in
string theory.Comment: 5 pages; v2: typos, add references; v3: major revision, add WCP4
hypersurface example, add references, published versio

### Multi-Messenger Theories of Gauge-Mediated Supersymmetry Breaking

We study gauge-mediated theories containing several messengers with the most
general SU(5)-invariant mass and supersymmetry-breaking parameters. We show
that these theories are predictive, containing only two relevant parameters
more than the minimal gauge-mediated model. Hypercharge D-terms can contribute
significantly to the right-handed charged sleptons and bring them closer in
mass to the left-handed sleptons. The messenger masses must be invariant under
either SU(5) or a ``messenger parity" to avoid spontaneous breaking of charge
conservation.Comment: 13 pages, 2 figure

### Extracting Supersymmetry-Breaking Effects from Wave-Function Renormalization

We show that in theories in which supersymmetry breaking is communicated by
renormalizable perturbative interactions, it is possible to extract the soft
terms for the observable fields from wave-function renormalization. Therefore
all the information about soft terms can be obtained from anomalous dimensions
and beta functions, with no need to further compute any Feynman diagram. This
method greatly simplifies calculations which are rather involved if performed
in terms of component fields. For illustrative purposes we reproduce known
results of theories with gauge-mediated supersymmetry breaking. We then use our
method to obtain new results of phenomenological importance. We calculate the
next-to-leading correction to the Higgs mass parameters, the two-loop soft
terms induced by messenger-matter superpotential couplings, and the soft terms
generated by messengers belonging to vector supermultiplets.Comment: Typos corrected, version to appear in Nucl. Phys.

### A Solution to the $\mu$ Problem in Gauge-mediated Supersymmetry-breaking Models

We point out that a sector required to set the cosmological constant to zero
in gauge-mediated supersymmetry-breaking models naturally produces a
supersymmetry-invariant mass ($\mu$ term) for Higgs doublets of the order of
the electroweak scale. Since this new sector preserves the supersymmetry, it
does not generate supersymmetry-breaking masses for the Higgs doublets and thus
the $\mu$ problem is solved.Comment: Latex fil

### Inflation and the Nature of Supersymmetry Breaking

The scale at which supersymmetry is broken and the mechanism by which
supersymmetry breaking is fed down to the observable sector has rich
implications on the way Nature may have chosen to accomplish inflation. We
discuss a simple model for slow rollover inflation which is minimal in the
sense that the inflaton may be identified with the field responsible for the
generation of the $\mu$-term. Inflation takes place at very late times and is
characterized by a very low reheating temperature. This property is crucial to
solve the gravitino problem and may help to ameliorate the cosmological moduli
problem. The COBE normalized value of the vacuum energy driving inflation is
naturally of the order of $10^{11}$ GeV. This favors the N=1 supergravity
scenario where supersymmetry breaking is mediated by gravitational
interactions. Nonetheless, smaller values of the vacuum energy are not excluded
by present data on the temperature anisotropy and the inflationary scenario may
be implemented in the context of new recent ideas about gauge mediation where
the standard model gauge interactions can serve as the messangers of
supersymmetry breaking. In this class of models supersymmetry breaking masses
are usually prop ortional to the F-term of a gauge singlet superfield. The same
F-term may provide the vacuum energy density necessary to drive inflation. The
spectrum of density perturbations is characterized by a spectral index which is
significantly displaced from one. The measurements of the temperature
anisotropies in the cosmic microwave background radiation at the accuracy
expected to result from the planned missions will be able to confirm or
disprove this prediction and to help in getting some deeper insight into the
nature of supersymmetry breaking.Comment: 25 pages, LaTeX fil

### Renormalization of Higher Derivative Operators in the Matrix Model

$M$-theory is believed to be described in various dimensions by large $N$
field theories. It has been further conjectured that at finite $N$, these
theories describe the discrete light cone quantization (DLCQ) of $M$ theory.
Even at low energies, this is not necessarily the same thing as the DLCQ of
supergravity. It is believed that this is only the case for quantities which
are protected by non-renormalization theorems. In 0+1 and 1+1 dimensions, we
provide further evidence of a non-renormalization theorem for the $v^4$ terms,
but also give evidence that there are not such theorems at order $v^8$ and
higher.Comment: 14 pages latex. Note added in light of recent development

### Enhanced Symmetries and the Ground State of String Theory

The ground state of string theory may lie at a point of ``maximally enhanced
symmetry", at which all of the moduli transform under continuous or discrete
symmetries. This hypothesis, along with the hypotheses that the theory at high
energies has N=1 supersymmetry and that the gauge couplings are weak and
unified, has definite consequences for low energy physics. We describe these,
and offer some suggestions as to how these assumptions might be compatible.Comment: harvmac, 18 page

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