1,676 research outputs found

    Top Quark as a Dark Portal and Neutrino Mass Generation

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    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 upup-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 μ→eγ\mu\to e\gamma, 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

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    In this study we explore the LHC's Run II potential to the discovery of heavy Majorana neutrinos, with luminosities between 3030 and 30003000 fb−1^{-1} in the l±l±j jl^{\pm}l^{\pm}j~j 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 100100 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

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    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 psicología en la Universidad de Barcelona, las raíces de su interés por la psicología 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 psicología transpersonal, sus primeras publicaciones en el 'Journal of Transpersonal Psychology' y su debate con Ken Wilber, así 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 psicología transpersonal actualmente, sus intereses principales y sus proyectos futuro

    Hardy type spaces on certain noncompact manifolds and applications

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    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

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    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

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    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

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    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

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    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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