1,971 research outputs found
A light Higgs scenario based on the TeV-scale supersymmetric strong dynamics
We consider a model based on the supersymmetric QCD theory with N_c=2 and
N_f=3. The theory is strongly coupled at the infrared scale \Lambda_H. Its low
energy effective theory below \Lambda_H is described by the supersymmetric
standard model with the Higgs sector that contains four iso-spin doublets, two
neutral iso-spin singlets and two charged iso-spin singlets. If \Lambda_H is at
the multi-TeV to 10 TeV, coupling constants for the F-terms of these composite
fields are relatively large at the electroweak scale. Nevertheless, the SM-like
Higgs boson is predicted to be as light as 125 GeV because these F-terms
contribute to the mass of the SM-like Higgs boson not at the tree level but at
the one-loop level. A large non-decoupling effect due to these F-terms appears
in the one-loop correction to the triple Higgs boson coupling, which amounts to
a few tens percent. Such a non-decoupling property in the Higgs potential
realizes the strong first order phase transition, which is required for a
successful scenario of electroweak baryogenesis
Gravitational Backreaction Effects on the Holographic Phase Transition
We study radion stabilization in the compact Randall-Sundrum model by
introducing a bulk scalar field, as in the Goldberger and Wise mechanism, but
(partially) taking into account the backreactions from the scalar field on the
metric. Our generalization reconciles the radion potential found by Goldberger
and Wise with the radion mass obtained with the so-called superpotential method
where backreaction is fully considered. Moreover we study the holographic phase
transition and its gravitational wave signals in this model. The improved
control over backreactions opens up a large region in parameter space and
leads, compared to former analysis, to weaker constraints on the rank N of the
dual gauge theory. We conclude that, in the regime where the 1/N expansion is
justified, the gravitational wave signal is detectable by LISA.Comment: 42 pages, 4 figures; v2: minor changes for the publicatio
Supersymmetric CP-violating Currents and Electroweak Baryogenesis
In this work we compute the CP-violating currents of the right-handed stops
and Higgsinos, induced by the presence of non-trivial vacuum expectation values
of the Higgs fields within the context of the minimal supersymmetric extension
of the Standard Model (MSSM) with explicit CP-violating phases. Using the
Keldysh formalism, we perform the computation of the currents at finite
temperature, in an expansion of derivatives of the Higgs fields. Contrary to
previous works, we implement a resummation of the Higgs mass insertion effects
to all orders in perturbation theory. While the components of the right-handed
stop current j^\mu_{\widetilde t_R} become proportional to the difference H_2
\partial^{\mu}H_1-H_1 \partial^{\mu} H_2 (suppressed by \Delta\beta), the
Higgsino currents, j^\mu_{\widetilde{H}_i}, present contributions proportional
to both H_2 \partial^{\mu}H_1\pm H_1 \partial^{\mu} H_2. For large values of
the charged Higgs mass and moderate values of \tan\beta the contribution to the
source proportional to H_2 \partial^{\mu}H_1+H_1 \partial^{\mu} H_2 in the
diffusion equations become sizeable, although it is suppressed by the Higgsino
number violating interaction rate \Gamma_\mu^{-1/2}. For small values of the
wall velocity, 0.04\simlt v_\omega \simlt 0.1, the total contribution leads to
acceptable values of the baryon asymmetry for values of the CP-violating phases
\phi_{CP} in the range 0.04\simlt|\sin\phi_{CP}|\simlt 1. Finally, we comment
on the relevance of the latest results of Higgs searches at LEP2 for the
mechanism of electroweak baryogenesis within the MSSM.Comment: 27 pages, 4 figures, latex2e. Typo corrected and references adde
Las Juntas Rurales de Credito en Costa Rica
This paper examines the recent evolution of the Juntas Rurales of the Banco Nacional de Costa Rica, at one time a very successful network of rural bank branches. The nature and causes of the recent contraction of their activities are explored in detail, including changes in the macroeconomic environment and in financial policies as well as the restructuring of the Banco Nacional. The determinants of their earlier success are identified and present policies and procedures are evaluated in contrast with those that contributed to that success. The elements of a new program of financial services for small entrepreneurs are outlined. This program would replicate some of the features of the earlier system, adapted to the new environment. A specific plan of action is suggested
GOVERNANCE OF TECHNOLOGICAL INNOVATION IN THE TROPICAL FRUIT COMMODITY CHAINS IN LATIN AMERICA
N° ISBN - 978-2-7380-1284-5International audienceThe analyses mobilized costs conventional benefits for the evaluation ex ante of the feasibility of technical innovations in the agri-foodstuffs chains are criticized in their capacity to integrate the economic and environmental externalities that structure the development of the innovations. This communication proposes to undergo a methodology that puts in complementariness diagnoses, participating analyses multicriterion and investigations with actors of chains for the evaluation ex-ante of the feasibility of technical innovations different. The application is realised in different chains from processing of fruits in Latin America (Brazil, Costa Rica, Ecuador, Mexico). The results allow to characterize that the conditions of supplying in matera premium (fresh fruit) and the conditions of organization of the chains in the implementation of interactions between different actors; they are strategic elements of the feasibility. On the other hand they show the necessity to improve the methodologic picture proposed to activate âsystems of chain innovationsâ that improve the processes of gobernancia of the technological directions in relation to their environmental impacts and social
Ion species fractions in the far-field plume of a high-specific impulse Hall thruster
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76418/1/AIAA-2003-5001-731.pd
The Effective Theory of the Light Stop Scenario
Electroweak baryogenesis in the minimal supersymmetric extension of the
Standard Model may be realized within the light stop scenario, where the
right-handed stop mass remains close to the top-quark mass to allow for a
sufficiently strong first order electroweak phase transition. All other
supersymmetric scalars are much heavier to comply with the present bounds on
the Higgs mass and the electron and neutron electric dipole moments. Heavy
third generation scalars render it necessary to resum large logarithm
contributions to perform a trustable Higgs mass calculation. We have studied
the one--loop RGE improved effective theory below the heavy scalar mass scale
and obtained reliable values of the Higgs mass. Moreover, assuming a common
mass for all heavy scalar particles, and values of all gaugino
masses and the Higgsino mass parameter about the weak scale, and imposing gauge
coupling unification, a two-loop calculation yields values of the mass in the interval between three TeV and six hundred TeV. Furthermore for a
stop mass around the top quark mass, this translates into an upper bound on the
Higgs mass of about 150 GeV. The Higgs mass bound becomes even stronger, of
about 129 GeV, for the range of stop and gaugino masses consistent with
electroweak baryogenesis. The collider phenomenology implications of this
scenario are discussed in some detail.Comment: 28 pages, 13 figures, uses axodraw.sty; v2: To appear in JHE
Supersymmetry and Electroweak Breaking in the Interval
Hypermultiplets are considered in the five-dimensional interval where all
fields are continuous and the boundary conditions are dynamically obtained from
the action principle. The orbifold boundary conditions are obtained as
particular cases. We can interpret the Scherk-Schwarz supersymmetry breaking as
a misalignment of boundary conditions while a new source of supersymmetry
breaking corresponding to a mismatch of different boundary parameters is
identified. The latter can be viewed as coming from boundary supersymmetry
breaking masses for hyperscalars and the nature of the corresponding
supersymmetry breaking parameter is analyzed. For some regions of the parameter
space where supersymmetry is broken (either by Scherk-Schwarz boundary
conditions or by boundary hyperscalar masses) electroweak symmetry breaking can
be triggered at the tree level.Comment: 28 pages, 5 figure
Light Dark Matter and the Electroweak Phase Transition in the NMSSM
We analyze the stability of the vacuum and the electroweak phase transition
in the NMSSM close to the Peccei-Quinn symmetry limit. This limit contains
light Dark Matter (DM) particles with a mass significantly smaller than the
weak scale and also light CP-even and CP-odd Higgs bosons. Such light particles
lead to a consistent relic density and facilitate a large spin-independent
direct DM detection cross section, that may accommodate the recently reported
signatures at the DAMA and CoGeNT experiments. Studying the one-loop effective
potential at finite temperature, we show that when the lightest CP-even Higgs
mass is of the order of a few GeV, the electroweak phase transition tends to
become first order and strong. The inverse relationship between the
direct-detection cross-section and the lightest CP-even Higgs mass implies that
a cross-section of the order of 10 cm is correlated with a strong
first order phase transition.Comment: 28 Pages, 15 figure
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