Phenomenology of Higgsless Models at the LHC and the ILC

We investigate the signatures of the recently proposed Higgsless models at future colliders. We focus on tests of the mechanism of partial unitarity restoration in the longitudinal vector boson scattering, which do not depend on any Higgsless model-building details. We study the LHC discovery reach for charged massive vector boson resonances and show that all of the preferred parameter space will be probed with $100 {\rm fb}^{-1}$ of LHC data. We also discuss the prospects for experimental verification of the Higgsless nature of the model at the LHC. In addition, in this talk we present new results relevant for the discovery potential of Higgsless models at the International Linear Collider (ILC).Comment: 6 pages, 6 figures, to appear in the proceedings of the 2005 International Linear Collider Workshop, Stanford, US

Spin-flop transitions and spin-wave gaps in La_2CuO_4

We study the spin-wave spectrum and the spin-flop transitions in La_2CuO_4 in a uniform magnetic field at zero temperature. Using the non-linear sigma-model, we show that a field applied along the orthorhombic b direction leads to a two-step rotation of the staggered magnetization, first in the bc and then in the ac plane, until the order parameter is completely aligned along the c axis. In contrast, for a perpendicular magnetic field, we find a conventional spin-flop transition induced by the competition between the field and the interlayer coupling. A comparison with recent measurements of the field-dependence of the in-plane spin-wave gap shows a beautiful agreement between theory and experiments.Comment: 7 pages, 3 figures; added referenc

Mean lattice point discrepancy bounds, II: Convex domains in the plane

We consider planar curved strictly convex domains with no or very weak smoothness assumptions and prove sharp bounds for square-functions associated to the lattice point discrepancy.Comment: Revised version, to appear in Journal d'Analyse Mathematiqu

Detailed chemical abundance analysis of the thick disk star cluster Gaia 1

Star clusters, particularly those objects in the disk-bulge-halo interface are as of yet poorly charted, albeit carrying important information about the formation and the structure of the Milky Way. Here, we present a detailed chemical abundance study of the recently discovered object Gaia 1. Photometry has previously suggested it as an intermediate-age, moderately metal-rich system, although the exact values for its age and metallicity remained ambiguous in the literature. We measured detailed chemical abundances of 14 elements in four red giant members, from high-resolution (R=25000) spectra that firmly establish Gaia 1 as an object associated with the thick disk. The resulting mean Fe abundance is $-0.62\pm$0.03(stat.)$\pm$0.10(sys.) dex, which is more metal-poor than indicated by previous spectroscopy from the literature, but it is fully in line with values from isochrone fitting. We find that Gaia 1 is moderately enhanced in the $\alpha$-elements, which allowed us to consolidate its membership with the thick disk via chemical tagging. The cluster's Fe-peak and neutron-capture elements are similar to those found across the metal-rich disks, where the latter indicate some level of $s$-process activity. No significant spread in iron nor in other heavy elements was detected, whereas we find evidence of light-element variations in Na, Mg, and Al. Nonetheless, the traditional Na-O and Mg-Al (anti-)correlations, typically seen in old globular clusters, are not seen in our data. This confirms that Gaia 1 is rather a massive and luminous open cluster than a low-mass globular cluster. Finally, orbital computations of the target stars bolster our chemical findings of Gaia 1's present-day membership with the thick disk, even though it remains unclear, which mechanisms put it in that place.Comment: 11 pages, 11 figures, accepted for publication in Astronomy & Astrophysics. Some figure sizes reduce

Endogenous enforcement of intellectual property, North-South trade, and growth

While most countries have harmonized intellectual property rights (IPR) legislation, the dispute about the optimal level of IPR-enforcement remains. This paper develops an endogenous growth framework with two open economies satisfying the classical North-South assumptions to study (a) IPR-enforcement in a decentralized game and (b) the desired globally-harmonized IPR-enforcement of the two regions. The results are compared to the constrained-efficient enforcement level. Our main insights are: The regions' desired harmonized enforcement levels are higher than their equilibrium choices, however, the gap between the two shrinks with relative market size. While growth rates substiantially increase when IPR-enforcement is harmonized at the North's desired level, our numerical simulation suggests that the South may also benefit in terms of long-run welfare. --Endogenous Growth,Intellectual Property Rights,Trade,Dynamic Game

Electromagnetic form factors of bound nucleons revisited

We investigate the possible modifications of the nucleons' electromagnetic form factors in the framework of a modified Skyrme model allowing for nucleon deformation and using realistic nuclear mass distributions. We show that such effects are small in light nuclei.Comment: 5 pp, 2 figure

A universal ionization threshold for strongly driven Rydberg states

We observe a universal ionization threshold for microwave driven one-electron Rydberg states of H, Li, Na, and Rb, in an {\em ab initio} numerical treatment without adjustable parameters. This sheds new light on old experimental data, and widens the scene for Anderson localization in light matter interaction.Comment: 4 pages, 1 figur