34,468 research outputs found
Effective Supergravity from the Weakly Coupled Heterotic String
The motivation for Calabi-Yau-like compactifications of the weakly coupled
heterotic string theory, its particle spectrum and the issue
of dilaton stabilization are briefly reviewed. Modular invariant models for
hidden sector condensation and supersymmetry breaking are described at the
quantum level of the effective field theory. Their phenomenological and
cosmological implications, including a possible origin for R-parity, are
discussed.Comment: 17 pages, Talk presented at the Symposium in honor of Julius Wess,
Jan. 10--11, 200
Multi-parametric solutions to the NLS equation
The structure of the solutions to the one dimensional focusing nonlin-ear
Schr{\"o}dinger equation (NLS) for the order N in terms of quasi rational
functions is given here. We first give the proof that the solutions can be
expressed as a ratio of two wronskians of order 2N and then two determinants by
an exponential depending on t with 2N -- 2 parameters. It also is proved that
for the order N , the solutions can be written as the product of an exponential
depending on t by a quotient of two polynomials of degree N (N + 1) in x and t.
The solutions depend on 2N -- 2 parameters and give when all these parameters
are equal to 0, the analogue of the famous Peregrine breather PN. It is
fundamental to note that in this representation at order N , all these
solutions can be seen as deformations with 2N -- 2 parameters of the famous
Peregrine breather PN. With this method, we already built Peregrine breathers
until order N = 10, and their deformations depending on 2N -- 2 parameters
One Loop Soft Supersymmetry Breaking Terms in Superstring Effective Theories
We perform a systematic analysis of soft supersymmetry breaking terms at the
one loop level in a large class of string effective field theories. This
includes the so-called anomaly mediated contributions. We illustrate our
results for several classes of orbifold models. In particular, we discuss a
class of models where soft supersymmetry breaking terms are determined by quasi
model independent anomaly mediated contributions, with possibly non-vanishing
scalar masses at the one loop level. We show that the latter contribution
depends on the detailed prescription of the regularization process which is
assumed to represent the Planck scale physics of the underlying fundamental
theory. The usual anomaly mediation case with vanishing scalar masses at one
loop is not found to be generic. However gaugino masses and A-terms always
vanish at tree level if supersymmetry breaking is moduli dominated with the
moduli stabilized at self-dual points, whereas the vanishing of the B-term
depends on the origin of the mu-term in the underlying theory. We also discuss
the supersymmetric spectrum of O-I and O-II models, as well as a model of
gaugino condensation. For reference, explicit spectra corresponding to a Higgs
mass of 114 GeV are given. Finally, we address general strategies for
distinguishing among these models.Comment: 49 pages: includes three tables and nine figure
Phenomenology and cosmology of weakly coupled string theory
The weakly coupled vacuum of heterotic string theory remains
an attractive scenario for phenomenolgy and cosmology. The particle spectrum is
reviewed and the issues of gauge coupling unification, dilaton stabilization
and modular cosmology are discussed. A specific model for condensation and
supersymmetry breaking, that respects known constraints from string theory and
is phenomenologically viable, is described.Comment: 24 pages, talk presented at The Richard Arnowitt Fest, April 5-8,
1998, Texas A & M University, College Station, TX, to be published in the
proceedings, full postscript available from
http://phyweb.lbl.gov/theorypapers/preprints.html/41110.p
Equity and Health
This article raises the problem of equity in the health system in Switzerland. Three dimensions of the concept of equity are taken into consideration: the inequality in the financing of the health system, the inequality in the distri-bution of the state of good health, and, finally, the iniquity in the access to health care. Some methodological devel-opments are presented as well as the results. In conclusion we observe that the state of good health does not depend strongly on income but that it exists some iniquity in the access to health services from specialists and that the in-come inequality is increasing due to the financing of the health system.health system; equity
Quantum-Induced Soft Supersymmetry Breaking In Supergravity
We calculate the one-loop quantum contributions to soft supersymmetry
breaking terms in the scalar potential in supergravity theories regulated \`a
la Pauli-Villars. We find ``universal'' contributions, independent of the
regulator masses and tree level soft supersymmetry breaking, that contribute
gaugino masses and A-terms equal to the ``anomaly mediated'' contributions
found in analyses using spurion techniques, as well as a scalar mass term not
identified in those analyses. The universal terms are in general modified --
and in some cases canceled -- by model-dependent terms. Under certain
restrictions on the couplings we recover the one-loop results of previous
``anomaly mediated'' supersymmetry breaking scenarios. We emphasize the model
dependence of loop-induced soft terms in the potential, which are much more
sensitive to the details of Planck scale physics then are the one-loop
contributions to gaugino masses. We discuss the relation of our results to
previous analyses.Comment: 18 pages. This replacement corrects eqs. (7) and (31) and adds
clarifying comments after eq. (11) and before eq. (18
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