12,030 research outputs found
A clean signal for a top-like isosinglet fermion at the Large Hadron Collider
We predict a clean signal at the Large Hadron Collider (=14 TeV for
a scenario where there is a top-like, charge +2/3 vectorlike isosinglet
fermion. Such a quark, via mixing with the standard model top, can undergo
decays via both flavour-changing Z-boson coupling and flavour-changing Yukawa
interactions. We concentrate on the latter channel, and study the situation
where, following its pair-production, the heavy quark pair gives rise to two
tops and two Higgs boson. We show that the case where each Higgs decays in the
channel, there can be a rather distinct and background-free signal
that can unveil the existence of the vectorlike isosinglet quark of this kind.Comment: 14 pages, 5 figures, 4 table
The Effective Lagrangian for Bulk Fermions in Models with Extra Dimensions
We compute the dimension 6 effective Lagrangian arising from the tree level
integration of an arbitrary number of bulk fermions in models with warped extra
dimensions. The coefficients of the effective operators are written in terms of
simple integrals of the metric and are valid for arbitrary warp factors, with
or without an infrared brane, and for a general Higgs profile. All relevant
tree level fermion effects in electroweak and flavor observables can be
computed using this effective Lagrangian.Comment: 22 pages. V2: typos corrected, matches published versio
Memoria Académica 2014-2015
El CABD es un centro mixto de investigación. Actualmente, el centro lo ocupan 19 grupos
trabajando en desarrollo de ratón, pez cebra, Xenopus, Drosophila y Caenorhabditis, así como estudiando
control del ciclo celular en levaduras, regulación génica en bacterias y estrés oxidativo. El CABD es el
único centro español especializado en el estudio de la Biología del Desarrollo. Esta especialidad investiga
los mecanismos genéticos y moleculares que controlan cómo las células crecen, se comunican y se
diferencian formando órganos complejos. Se ha comprobado que los genes que controlan el desarrollo
animal están regulados de modo anómalo en muchas enfermedades humanas. Por tanto, el conocimiento
de la función normal de estos genes ayudará a diseñar nuevas estrategias para prevenir o solucionar
estos problemas.
El CABD se encuentra en fase de expansión, teniendo como objetivo atraer tanto a científicos
españoles como extranjeros.
El Centro está cofinanciado por el Consejo Superior de Investigaciones Científicas (CSIC), la Junta
de Andalucía y la Universidad Pablo de Olavide (UPO), de Sevilla. La edificación y el equipamiento fueron
costeados con fondos de la Unión Europea.N
Memoria Curso Académico 2013-2014
El CABD es un centro mixto financiado por el Consejo Superior de Investigaciones Científicas, la
Junta de Andalucía y la Universidad Pablo de Olavide. Actualmente el centro lo ocupan 17 grupos
trabajando en desarrollo de ratón, pez cebra, Xenopus, Drosophila y Caenorhabditis, así como estudiando
control del ciclo celular en levaduras, regulación génica en bacterias y estrés oxidativo. El CABD es el
único centro español especializado en el estudio de la Biología del Desarrollo. Esta especialidad investiga
los mecanismos genéticos y moleculares que controlan cómo las células crecen, se comunican y se
diferencian formando órganos complejos. Se ha comprobado que los genes que controlan el desarrollo
animal están regulados de modo anómalo en muchas enfermedades humanas. Por tanto, el conocimiento
de la función normal de estos genes ayudará a diseñar nuevas estrategias para prevenir o solucionar
estos problemas.
El Centro está cofinanciado por el Consejo Superior de Investigaciones Científicas (CSIC), la Junta
de Andalucía y la Universidad Pablo de Olavide (UPO), de Sevilla. La edificación y el equipamiento fueron
costeados con fondos de la Unión Europea.N
Memoria Curso Académico 2012-2013
El CABD es un centro mixto financiado por el Consejo Superior de Investigaciones Científicas, la
Junta de Andalucía y la Universidad Pablo de Olavide. Actualmente, el Centro lo ocupan 17 grupos
trabajando en desarrollo de ratón, pez cebra, Xenopus, Drosophila y Caenorhabditis, así como estudiando
control del ciclo celular en levaduras, regulación génica en bacterias y estrés oxidativo. El CABD es el
único centro español especializado en el estudio de la Biología del Desarrollo. Esta especialidad investiga
los mecanismos genéticos y moleculares que controlan cómo las células crecen, se comunican y se
diferencian formando órganos complejos. Se ha comprobado que los genes que controlan el desarrollo
animal están regulados de modo anómalo en muchas enfermedades humanas. Por tanto, el conocimiento
de la función normal de estos genes ayudará a diseñar nuevas estrategias para prevenir o solucionar
estos problemas.
El Centro está cofinanciado por el Consejo Superior de Investigaciones Científicas (CSIC), la Junta
de Andalucía y la Universidad Pablo de Olavide (UPO), de Sevilla. La edificación y el equipamiento fueron
costeados con fondos de la Unión Europea.N
An Entangled Model for Sustainability Indicators.
Nowadays the challenge for humanity is to find pathways towards sustainable development. Decision makers require a set of sustainability indicators to know if the sustainability strategies are following those pathways. There are more than one hundred sustainability indicators but they differ on their relative importance according to the size of the locality and change on time. The resources needed to follow these sustainability indicators are scarce and in some instances finite, especially in smaller regions. Therefore strategies to select set of these indicators are useful for decision makers responsible for monitoring sustainability. In this paper we propose a model for the identification and selection of a set of sustainability indicators that adequately represents human systems. In developing this model, we applied evolutionary dynamics in a space where sustainability indicators are fundamental entities interconnected by an interaction matrix. we used a fixed interaction that simulates the current context for the city of Cuernavaca, México as an example. We were able to identify and define relevant sets indicators for the system by using the Pareto principle. In this case we identified a set of sixteen sustainability indicators with more than 80% of the total strength. This set presents resilience to perturbations. For the Tangled Nature framework we provided a manner of treating different contexts (i.e., cities, counties, states, regions, countries, continents or the whole planet), dealing with small dimensions. This model provides decision makers with a valuable tool to select sustainability indicators set for towns, cities, regions, countries, continents or the entire planet according to a coevolutionary framework. The social legitimacy can arise from the fact that each individual indicator must be selected from those that are most important for the subject community
Top quark tensor couplings
We compute the real and imaginary parts of the one-loop electroweak
contributions to the left and right tensorial anomalous couplings of the
vertex in the Standard Model (SM). For both tensorial couplings we find that
the real part of the electroweak SM correction is close to 10 of the leading
contribution given by the QCD gluon exchange. We also find that the electroweak
real and imaginary parts for the anomalous right coupling are almost of the
same order of magnitude. The one loop SM prediction for the real part of the
left coupling is close to the 3 discovery limit derived from
. Besides, taking into account that the predictions of
new physics interactions are also at the level of a few percents when compared
with the one loop QCD gluon exchange, these electroweak corrections should be
taken into account in order to disentangle new physics effects from the
standard ones. These anomalous tensorial couplings of the top quark will be
investigated at the LHC in the near future where sensitivity to these
contributions may be achieved.Comment: 16 pages, 2 figure
Neutrino physics at large colliders
Large colliders are not sensitive to light neutrino masses and character, but
they can produce new heavy neutrinos, allowing also for the determination of
their Dirac or Majorana nature. We review the discovery limits at the next
generation of large colliders.Comment: LaTeX 32 pages. This review summarises and extends work presented at
several conferences. To appear in the proceedings of CORFU2005. References
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Model-Independent Searches for New Quarks at the LHC
New vector-like quarks can have sizable couplings to first generation quarks
without conflicting with current experimental constraints. The coupling with
valence quarks and unique kinematics make single production the optimal
discovery process. We perform a model-independent analysis of the discovery
reach at the Large Hadron Collider for new vector-like quarks considering
single production and subsequent decays via electroweak interactions. An early
LHC run with 7 TeV center of mass energy and 1 fb-1 of integrated luminosity
can probe heavy quark masses up to 1 TeV and can be competitive with the
Tevatron reach of 10 fb-1. The LHC with 14 TeV center of mass energy and 100
fb-1 of integrated luminosity can probe heavy quark masses up to 3.7 TeV for
order one couplings.Comment: 37 pages, 11 figures, 7 table
Loop lessons from Wilson loops in N=4 supersymmetric Yang-Mills theory
N=4 supersymmetric Yang-Mills theory exhibits a rather surprising duality of
Wilson-loop vacuum expectation values and scattering amplitudes. In this paper,
we investigate this correspondence at the diagram level. We find that one-loop
triangles, one-loop boxes, and two-loop diagonal boxes can be cast as simple
one- and two- parametric integrals over a single propagator in configuration
space. We observe that the two-loop Wilson-loop "hard-diagram" corresponds to a
four-loop hexagon Feynman diagram. Guided by the diagrammatic correspondence of
the configuration-space propagator and loop Feynman diagrams, we derive Feynman
parameterizations of complicated planar and non-planar Feynman diagrams which
simplify their evaluation. For illustration, we compute numerically a four-loop
hexagon scalar Feynman diagram.Comment: 20 pages, many figures. Two references added. Published versio
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