114 research outputs found
The degenerate gravitino scenario
In this work, we explore the "degenerate gravitino" scenario where the mass
difference between the gravitino and the lightest MSSM particle is much smaller
than the gravitino mass itself. In this case, the energy released in the decay
of the next to lightest sypersymmetric particle (NLSP) is reduced. Consequently
the cosmological and astrophysical constraints on the gravitino abundance, and
hence on the reheating temperature, become softer than in the usual case. On
the other hand, such small mass splittings generically imply a much longer
lifetime for the NLSP. We find that, in the constrained MSSM (CMSSM), for
neutralino LSP or NLSP, reheating temperatures compatible with thermal
leptogenesis are reached for small splittings of order 10^{-2} GeV. While for
stau NLSP, temperatures of 4x10^9 GeV can be obtained even for splittings of
order of tens of GeVs. This "degenerate gravitino" scenario offers a possible
way out to the gravitino problem for thermal leptogenesis in supersymmetric
theories.Comment: 27 pages, 10 figures and 1 table. Minor typos and references fixed.
Matches published version in JCAP
Slepton Non-Universality in the Flavor-Effective MSSM
Supersymmetric theories supplemented by an underlying flavor-symmetry
provide a rich playground for model building aimed at
explaining the flavor structure of the Standard Model. In the case where
supersymmetry breaking is mediated by gravity, the soft-breaking Lagrangian
typically exhibits large tree-level flavor violating effects, even if it stems
from an ultraviolet flavor-conserving origin. Building on previous work, we
continue our phenomenological analysis of these models with a particular
emphasis on leptonic flavor observables. We consider three representative
models which aim to explain the flavor structure of the lepton sector, with
symmetry groups , and .Comment: References added, minor typos corrected. 28 pages, 8 figure
CP violation as a probe of flavor origin in Supersymmetry
We address the question of the relation between supersymmetry breaking and
the origin of flavor in the context of CP violating phenomena. We prove that,
in the absence of the Cabibbo-Kobayashi-Maskawa phase, a general Minimal
Supersymmetric Standard Model with all possible phases in the soft-breaking
terms, but no new flavor structure beyond the usual Yukawa matrices, can never
give a sizeable contribution to , or
hadronic CP asymmetries. Observation of supersymmetric contributions to
CP asymmetries in B decays would hint at a non-flavor blind mechanism of
supersymmetry breaking.Comment: Reference added. 7 pages, no figure
Controlled flavor violation in the MSSM from a unified flavor symmetry
We study the phenomenology of a unified supersymmetric theory with a flavor
symmetry . The model accommodates quark and lepton masses, mixing
angles and CP phases. In this model, the Dirac and Majorana mass matrices have
a unified texture zero structure in the entry that leads to the
Gatto-Sartori-Tonin relation between the Cabibbo angle and ratios of the masses
in the quark sectors, and to a natural departure from zero of the
angle in the lepton sector. We derive the flavor structures
of the trilinears and soft mass matrices, and show their general
non-universality. This causes large flavor violating effects. As a consequence,
the parameter space for this model is constrained, allowing it to be
(dis)proven by flavor violation searches in the next decade. Although the
results are model specific, we compare them to previous studies to show similar
flavour effects (and associated constraints) are expected in general in
supersymmetric flavor models, and may be used to distinguish them.Comment: 21 pages, 6 figure
Gain modulation of synaptic inputs by network state in auditory cortex in vivo
The cortical network recurrent circuitry generates spontaneous activity organized into Up (active) and Down (quiescent) states during slow-wave sleep or anesthesia. These different states of cortical activation gain modulate synaptic transmission. However, the reported modulation that Up states impose on synaptic inputs is disparate in the literature, including both increases and decreases of responsiveness. Here, we tested the hypothesis that such disparate observations may depend on the intensity of the stimulation. By means of intracellular recordings, we studied synaptic transmission during Up and Down states in rat auditory cortex in vivo. Synaptic potentials were evoked either by auditory or electrical (thalamocortical, intracortical) stimulation while randomly varying the intensity of the stimulus. Synaptic potentials evoked by the same stimulus intensity were compared in Up/Down states. Up states had a scaling effect on the stimulus-evoked synaptic responses: the amplitude of weaker responses was potentiated whereas that of larger responses was maintained or decreased with respect to the amplitude during Down states. We used a computational model to explore the potential mechanisms explaining this nontrivial stimulus–response relationship. During Up/Down states, there is different excitability in the network and the neuronal conductance varies. We demonstrate that the competition between presynaptic recruitment and the changing conductance might be the central mechanism explaining the experimentally observed stimulus–response relationships. We conclude that the effect that cortical network activation has on synaptic transmission is not constant but contingent on the strength of the stimulation, with a larger modulation for stimuli involving both thalamic and cortical networks.Fil: Reig, Ramon. Institut d'Investigacions Biomèdiques August Pi i Sunyer; España. Karolinska Huddinge Hospital. Karolinska Institutet; SueciaFil: Zerlaut, Yann. Centre National de la Recherche Scientifique; Francia. Unité de Neurosciences, Information et Complexité; FranciaFil: Vergara, Ramiro Oscar. Institut d'Investigacions Biomèdiques August Pi i Sunyer; España. Consejo Nacional de Investigaciones CientÃficas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y TecnologÃa. Laboratorio de Acústica y Percepción Sonora; ArgentinaFil: Destexhe, Alain. Centre National de la Recherche Scientifique; Francia. Unité de Neurosciences, Information et Complexité; FranciaFil: Sánchez Vives, MarÃa V.. Institut d'Investigacions Biomèdiques August Pi i Sunyer; España. Institució Catalana de Recerca i Estudis Avancats; Españ
Música als curts. Un projecte d'innovació per a la lluita contra el fracàs escolar
El present document pretén mostrar un projecte d’innovació educativa per a la lluita contra el fracàs escolar a través de la realització d’activitats per a la promoció de la música. Aquest projecte, anomenat Música als curts, s’ha portat a terme al CEIP Heretats de l’Alcúdia durant el curs 2012-2013.This document shows us an innovative educational project to combat school failure through activities to promote music. This project, called Música als curts, has been carried out in the CEIP Heretats de l'Alcúdia during the school year 2012-2013
Diseñando paÃs: El valor del diseño
El presente documento propone una nueva aproximación al término diseño, en su concepción más amplia y cómo este enfoque aporta valor en el mundo de los negocios. Se toma como referencia los principios básicos y el pensamiento de diseño aplicados a casos de éxito
- …