1,676 research outputs found
Top Quark as a Dark Portal and Neutrino Mass Generation
We present a new model for radiatively generating Majorana active neutrino
masses while incorporating a viable dark matter candidate. This is possible by
extending the Standard Model with a single Majorana neutrino endowed with a
dark parity, a colour electroweak singlet scalar, as well as a colour
electroweak triplet scalar. Within this framework, the -type quarks play a
special role, serving as a portal for dark matter, and a messenger for neutrino
mass generation. We consider three benchmark scenarios where the abundance of
dark matter can match the latest experimental results, while generating
neutrino masses in the milli-electronvolt range. We show how constraints from
lepton flavour violation, in particular the branching fraction of , can place lower bounds on the coupling between our dark matter
candidate and top quarks. Furthermore, we show that this coupling can also be
constrained using collider data from the Tevatron and the LHC.Comment: 8 captions, 10 figure
Search for Heavy Right-Handed Neutrinos at the LHC and Beyond in the Same-Sign Same-Flavor Leptons Final State
In this study we explore the LHC's Run II potential to the discovery of heavy
Majorana neutrinos, with luminosities between and fb in the
final state. Given that there exist many models for
neutrino mass generation, even within the Type I seesaw framework, we use a
simplified model approach and study two simple extensions to the Standard
Model, one with a single heavy Majorana neutrino, singlet under the Standard
Model gauge group, and a limiting case of the left-right symmetric model. We
then extend the analysis to a future hadron collider running at TeV
center of mass energies. This extrapolation in energy allows us to study the
relative importance of the resonant production versus gauge boson fusion
processes in the study of Majorana neutrinos at hadron colliders. We analyze
and propose different search strategies designed to maximize the discovery
potential in either the resonant production or the gauge boson fusion modes
Participation and spirit : an interview with Jorge N. Ferrer
This interview with Jorge Ferrer explores a wide number of themes, ranging from his psychology studies at the University of Barcelona and the roots of his interest in transpersonal psychology to his arrival to San Francisco and first years at the California Institute of Integral Studies (CIIS) as a doctoral student. Topics discussed include his dissertation research, the publication of his first book 'Revisioning Transpersonal Theory' (SUNY Press, 2002), the participatory turn in transpersonal psychology, his first publications in the 'Journal of Transpersonal Psychology' and debate with Ken Wilber, and the development of the participatory paradigm in more recent years. Finally, Ferrer highlights what he considers to be the main issues and debates within transpersonal psychology, as well as shares his main current interests and future projectsEsta entrevista con Jorge Ferrer explora un amplio abanico de temas, comenzando por sus estudios de licenciatura en psicologÃa en la Universidad de Barcelona, las raÃces de su interés por la psicologÃa transpersonal, su llegada a San Francisco y sus primeros años en el CIIS y la ―Bay Area‖ como estudiante de doctorado. Los temas tratados incluyen su trabajo de tesis, la publicación de su primer libro 'Espiritualidad creativa', el giro participativo dentro de la psicologÃa transpersonal, sus primeras publicaciones en el 'Journal of Transpersonal Psychology' y su debate con Ken Wilber, asà como el desarrollo del paradigma participativo a lo largo de los últimos años. Finalmente, Ferrer destaca cuales considera que son los principales asuntos y debates en el campo de la psicologÃa transpersonal actualmente, sus intereses principales y sus proyectos futuro
Hardy type spaces on certain noncompact manifolds and applications
In this paper we consider a complete connected noncompact Riemannian manifold
M with Ricci curvature bounded from below, positive injectivity radius and
spectral gap b. We introduce a sequence X^1(M), X^2(M), ... of new Hardy spaces
on M, the sequence Y^1(M/, Y^2(M), ... of their dual spaces, and show that
these spaces may be used to obtain endpoint estimates for purely imaginary
powers of the Laplace-Beltrami operator and for more general spectral
multipliers associated to the Laplace--Beltrami operator L on M. Under the
additional condition that the volume of the geodesic balls of radius r is
controlled by C r^a e^{2\sqrt{b} r} for some real number a and for all large r,
we prove also an endpoint result for first order Riesz transforms D L^{-1/2}.
In particular, these results apply to Riemannian symmetric spaces of the
noncompact type.Comment: 27 pages, v2: the first version has been revised and rearranged, with
additions, in two papers, of which this new version is the first. The second
paper is posted as arXiv:1002.1161v
Signals of CP Violation Beyond the MSSM in Higgs and Flavor Physics
We study an extension of the Higgs sector of the Minimal Supersymmetric
Standard Model (MSSM), considering the effects of new degrees of freedom at the
TeV scale, and allowing for sources of CP violation beyond the MSSM (BMSSM). We
analyze the impact of the BMSSM sources of CP violation on the Higgs collider
phenomenology and on low energy flavor and CP violating observables. We
identify distinct Higgs collider signatures that cannot be realized, either in
the case without CP violating phases or in the CP violating MSSM, and
investigate the prospects to probe them at the Tevatron and the LHC. The most
striking benchmark scenario has three neutral Higgs bosons that all decay
dominantly into W boson pairs and that are well within the reach of the 7 TeV
LHC run. On the other hand, we also present scenarios with three Higgs bosons
that have masses M_Hi > 150 GeV and decay dominantly into b bbar. Such
scenarios are much more challenging to probe and can even lie completely
outside the reach of the 7 TeV LHC run. We explore complementary scenarios with
standard MSSM Higgs signals that allow to accommodate a sizable B_s mixing
phase as indicated by D0, as well as the excess in B_s --> mu+ mu- candidates
recently reported by CDF. We find that, in contrast to the MSSM, a minimal
flavor violating soft sector is sufficient to generate significant corrections
to CP violating observables in meson mixing, compatible with EDM constraints.
In particular, a sizable B_s mixing phase, S_psiphi < 0.4, can be achieved for
specific regions of parameter space. Such a large B_s mixing phase would
unambiguously imply a sizable suppression of S_psiKs with respect to the SM
prediction and a BR(B_s --> mu+ mu-) close to the 95% C.L. upper bound reported
by CDF.Comment: 58 pages, 15 figures, 2 tables, v2 matches published versio
Quasipolyhedral sets in linear semiinfinite inequality systems
AbstractThis paper provides an extension to linear semiinfinite systems of a well-known property of finite linear inequality systems, the so-called Weyl property, which characterizes the extreme points of the solution set as those solution points such that the gradient vectors of the active constraints form a complete set. A class of linear semiinfinite systems which satisfy this property is identified, the p-systems. It is also shown that any p-system contains an equivalent minimal subsystem
Performance comparison of multi-wavelength conversion using SOA-MZI and DSF for optical wavelength multicast
The electronic layer multicast is going to face the speed and capacity bottleneck of the future optical data networks. Transparent optical wavelength multicast by multi-wavelength conversion is an effective way of achieving data multicast in the optical domain without any optical-electronic-optical conversion. In this paper, two multiple wavelength conversion technologies for 10 Gb/s data rate are investigating and discussed. The first technology is based on cross-phase modulation in a semiconductor optical amplifier – Mach-Zehnder interferometer, and the second is based on four-wave mixing in a dispersion-shifted fiber. We present the simulated performance comparison of two approaches obtained using VPItransmissionMakerTMWDM simulator. Afterwards, we analyze these results in comparison with our previous experimental results of the same schemes
Artificially Disordered Birefringent Optical Fibers
We develop and experimentally verify a theory of evolution of polarization in artificially-disordered multi-mode optical fibers. Starting with a microscopic model of photo-induced index change, we obtain the first and second order statistics of the dielectric tensor in a Ge-doped fiber, where a volume disorder is intentionally inscribed via UV radiation transmitted through a diffuser. A hybrid coupled-power & coupled-mode theory is developed to describe the transient process of de-polarization of light launched into such a fiber. After certain characteristic distance, the power is predicted to be equally distributed over all co-propagating modes of the fiber regardless of their polarization. Polarization-resolved experiments, confirm the predicted evolution of the state of polarization. Complete mode mixing in a segment of fiber as short as ~ 10cm after 3.6dB insertion loss is experimentally observed. Equal excitation of all modes in such a multi-mode fiber creates the conditions to maximize the information capacity of the system under e.g. multiple-input-multiple-output (MIMO) transmission setup
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