Oblique Corrections in Deconstructed Higgsless Models

In this talk, using deconstruction, we analyze the form of the corrections to the electroweak interactions in a large class of ``Higgsless'' models of electroweak symmetry breaking, allowing for arbitrary 5-D geometry, position-dependent gauge coupling, and brane kinetic energy terms. Many models considered in the literature, including those most likely to be phenomenologically viable, are in this class. By analyzing the asymptotic behavior of the correlation function of gauge currents at high momentum, we extract the exact form of the relevant correlation functions at tree-level and compute the corrections to precision electroweak observables in terms of the spectrum of heavy vector bosons. We determine when nonoblique corrections due to the interactions of fermions with the heavy vector bosons become important, and specify the form such interactions can take. In particular we find that in this class of models, so long as the theory remains unitary, S - 4 c^2_W T > O(1), where S and T are the usual oblique parameters.Comment: 4 pages, 1 figure, to appear in the proceedings of SUSY 2004 : The 12th International Conference on Supersymmetry and Unification of Fundamental Interactions, held at Epochal Tsukuba, Tsukuba, Japan, June 17-23, 200

Multi-Gauge-Boson Vertices and Chiral Lagrangian Parameters in Higgsless Models with Ideal Fermion Delocalization

Higgsless models with fermions whose SU(2) properties are "ideally delocalized," such that the fermion's probability distribution is appropriately related to the W boson wavefunction, have been shown to minimize deviations in precision electroweak parameters. As contributions to the S parameter vanish to leading order, current constraints on these models arise from limits on deviations in multi-gauge-boson vertices. We compute the form of the triple and quartic gauge boson vertices in these models and show that these constraints provide lower bounds only of order a few hundred GeV on the masses of the lightest KK resonances. Higgsless models with ideal fermion delocalization provide an example of extended electroweak gauge interactions with suppressed couplings of fermions to extra gauge-bosons, and these are the only models for which triple-gauge-vertex measurements provide meaningful constraints. We relate the multi-gauge couplings to parameters of the electroweak chiral Lagrangian, and the parameters obtained in these SU(2) x SU(2) models apply equally to the corresponding five dimensional gauge theory models of QCD. We also discuss the collider phenomenology of the KK resonances in models with ideal delocalization. These resonances are found to be fermiophobic, therefore traditional direct collider searches are not sensitive to them and measurements of gauge-boson scattering will be needed to find them.Comment: 28 pages, 1 eps figure. Typo in reference correcte

Baryons with D5 Brane Vertex and k-Quarks

We study baryons in SU(N) gauge theories, according to the gauge/string correspondence based on IIB string theory. The D5 brane, in which $N$ fundamental strings are dissolved as a color singlet, is introduced as the baryon vertex, and its configurations are studied. We find point- and split-type of vertex. In the latter case, two cusps appears and they are connected by a flux composed of dissolved fundamental strings with a definite tension. In both cases, $N$ fundamental quarks are attached on the cusp(s) of the vertex to cancel the surface term. In the confining phase, we find that the quark in the baryon feel the potential increasing linearly with the distance from the vertex. At finite temperature and in the deconfining phase, we find a stable k-quarks "baryons", which are constructed of arbitrary number of $k(<N)$ quarks.Comment: 20 pages, 11 figure

Application of a CC-VSI for Active Filtering and Photovoltaic Energy Conversion with a 1-to-1 MPPT Controller

This paper focuses on the implementation of a three-phase four wire current-controlled Voltage Source Inverter (CC-VSI) as both PV energy extraction and power quality improvement. For power quality improvement, the CC-VSI works as a grid current-controller shunt active power filter. Then, the PV array supported by a Look-up Table type of a MPPT controller is coupled to the DC bus of the CC-VSI. The output of MPPT controller is a DC voltage that determines the DC-bus voltage according to the PV maximum power. The computer simulation results show that the system works properly in steady state and dynamic condition

Effects of Fermi surface and superconducting gap structure in the field-rotational experiments: A possible explanation of the cusp-like singularity in YNi2_2B2_2C

We have studied the field-orientational dependence of zero-energy density of states (FODOS) for a series of systems with different Fermi surface and superconducting gap structures. Instead of phenomenological Doppler-shift method, we use an approximate analytical solution of Eilenberger equation together with self-consistent determination of order parameter and a variational treatment of vortex lattice. First, we compare zero-energy density of states (ZEDOS) when a magnetic field is applied in the nodal direction ($\nu_{node}(0)$) and in the antinodal direction ($\nu_{anti}(0)$), by taking account of the field-angle dependence of order parameter. As a result, we found that there exists a crossover magnetic field $H^*$ so that $\nu_{anti}(0) > \nu_{node}(0)$ for $H \nu_{anti}(0)$ for $H > H^*$, consistent with our previous analyses. Next, we showed that $H^*$ and the shape of FODOS are determined by contribution from the small part of Fermi surface where Fermi velocity is parallel to field-rotational plane. In particular, we found that $H^*$ is lowered and FODOS has broader minima, when a superconducting gap has point nodes, in contrast to the result of the Doppler-shift method. We also studied the effects of in-plane anisotropy of Fermi surface. We found that in-plane anisotropy of quasi-two dimensional Fermi surface sometimes becomes larger than the effects of Doppler-shift and can destroy the Doppler-shift predominant region. In particular, this tendency is strong in a multi-band system where superconducting coherence lengths are isotropic. Finally, we addressed the problem of cusp-like singularity in YNi$_2$B$_2$C and present a possible explanation of this phenomenon.Comment: 13pages, 23figure

Identifying Better Effective Higgsless Theories via W_L W_L Scattering

The three site Higgsless model has been offered as a benchmark for studying the collider phenomenology of Higgsless models. In this talk, we present how well the three site Higgsless model performs as a general representative of Higgsless models in describing W_L W_L scattering, and which modifications can make it more representative. We employ general sum rules relating the masses and couplings of the Kaluza-Klein (KK) modes of the gauge fields in continuum and deconstructed Higgsless models as a way to compare the different theories. After comparing the three site Higgsless model to flat and warped continuum Higgsless models, we analyze an extensions of the three site Higgsless model, namely, the Hidden Local Symmetry (HLS) Higgsless model. We demonstrate that W_LW_L scattering in the HLS Higgsless model can very closely approximate scattering in the continuum models, provided that the parameter `a' is chosen to mimic rho-meson dominance of pi-pi scattering in QCD

General Sum Rules for WW Scattering in Higgsless Models: Equivalence Theorem and Deconstruction Identities

We analyze inelastic 2 to 2 scattering amplitudes for gauge bosons and Nambu-Goldstone bosons in deconstructed Higgsless models. Using the (KK) Equivalence Theorem in 4D (5D), we derive a set of general sum rules among the boson masses and multi-boson couplings that are valid for arbitrary deconstructed models. Taking the continuum limit, our results naturally include the 5D Higgsless model sum rules for arbitrary 5D geometry and boundary conditions; they also reduce to the elastic sum rules when applied to the special case of elastic scattering. For the case of linear deconstructed Higgsless models, we demonstrate that the sum rules can also be derived from a set of general deconstruction identities and completeness relations. We apply these sum rules to the deconstructed 3-site Higgsless model and its extensions; we show that in 5D ignoring all higher KK modes (n>1) is inconsistent once the inelastic channels become important. Finally, we discuss how our results generalize beyond the case of linear Higgsless models.Comment: 36 pages, 2 figure