6,613 research outputs found
Possible experimental signatures at the LHC of strongly interacting electro-weak symmetry breaking
If electro-weak symmetry is broken by a new strongly interacting sector, new
physics will probably manifest itself in gauge boson scattering at the LHC. The
relevant dynamics is well described in terms of an effective lagrangian. We
discuss the probable size of the coefficients of the relevant operators under a
combination of model-independent constraints and reasonable assumptions based
on two models of the strongly interacting sector. We compare these values with
LHC sensitivity and argue that they will be too small to be seen. Therefore,
the presence of vector and scalar resonances required by unitarity will be the
only characteristic signature. We analyze the most likely masses and widths of
these resonances.Comment: 14 pages, pdftex, 5 figures, improved discussion of bounds, 1
footnote remove
The bearable compositeness of leptons
Partial compositeness as a theory of flavor in the lepton sector is assessed. We begin presenting the first systematic analysis of neutrino mass generation in this context, and identifying the distinctive mass textures. We then update the bounds from charged lepton flavor and CP violating observables. We put forward a U(1)3 × CP symmetry of the composite sector, in order to allow the new physics to be not far above the TeV scale. This hypothesis effectively suppresses the new contributions to the electron EDM and μ → eγ, by far the most constraining observables, and results in a novel pattern of flavor violation and neutrino masses. The CP violation in the elementary-composite mixing is shown to induce a CKM phase of the correct size, as well as order-one phases in the PMNS matrix. We compare with the alternative possibility of introducing multiple scales of compositeness for leptons, that also allow to evade flavor and CP constraints. Finally, we examine violations of lepton flavor universality in B-meson semi-leptonic decays. The neutral-current anomalies can be accommodated, predicting strong correlations among different lepton flavors, with a few channels close to the experimental sensitivity
Intrinsic curvature of curves and surfaces and a Gauss-Bonnet theorem in the Heisenberg group
We use a Riemannnian approximation scheme to define a notion of intrinsic Gaussian curvature for a Euclidean C2 -smooth surface in the Heisenberg group H away from characteristic points, and a notion of intrinsic signed geodesic curvature for Euclidean C2 -smooth curves on surfaces. These results are then used to prove a Heisenberg version of the Gauss–Bonnet theorem. An application to Steiner’s formula for the Carnot–Carathéodory distance in H is provided
Tangible and intangible capital and the pattern of specialization in the EU
This paper investigates the determinants of specialisation in 7 European countries and 4 major industrial sectors in the last 20 years. Next to the impact of traditional factors such as productivity and the endowment of labour and capital, we look at the importance of accounting for capital heterogeneity, by distinguishing between ICT and non-ICT assets, and for intangible capital such as skills and R&D. Our results show that intangible capital and innovation play an important part in increasing the value added shares of the Manufacturing sector while increasing investments in ICT has driven resources away from Manufacturing and towards the Service industry
Sensitivity of the Cherenkov Telescope Array to a dark matter signal from the Galactic centre
We provide an updated assessment of the power of the Cherenkov Telescope Array (CTA) to search for thermally produced dark matter at the TeV scale, via the associated gamma-ray signal from pair-annihilating dark matter particles in the region around the Galactic centre. We find that CTA will open a new window of discovery potential, significantly extending the range of robustly testable models given a standard cuspy profile of the dark matter density distribution. Importantly, even for a cored profile, the projected sensitivity of CTA will be sufficient to probe various well-motivated models of thermally produced dark matter at the TeV scale. This is due to CTA's unprecedented sensitivity, angular and energy resolutions, and the planned observational strategy. The survey of the inner Galaxy will cover a much larger region than corresponding previous observational campaigns with imaging atmospheric Cherenkov telescopes. CTA will map with unprecedented precision the large-scale diffuse emission in high-energy gamma rays, constituting a background for dark matter searches for which we adopt state-of-the-art models based on current data. Throughout our analysis, we use up-to-date event reconstruction Monte Carlo tools developed by the CTA consortium, and pay special attention to quantifying the level of instrumental systematic uncertainties, as well as background template systematic errors, required to probe thermally produced dark matter at these energies
Status of the ANTARES detector
ANTARES (Astronomy with a Neutrino Telescope and Abyss environmental RESearch) is currently the largest neutrino observatory in the Northern hemisphere. The detector has been designed to detect high energy muon neutrinos coming from both galactic and extra-galactic sources, via the identification of muons, produced as the final state of charged current interactions of muon neutrinos with the medium surrounding the detector. The main goal of the ANTARES experiment is the search for high energy neutrinos of astrophysical origin. Besides the search for point-like steady sources, other physics topics are relevant for a deep
sea neutrino observatory. Some research topics that are presently pursued within the ANTARES Collaboration will be presented here
Monte Carlo studies for the optimisation of the Cherenkov Telescope Array layout
The Cherenkov Telescope Array (CTA) is the major next-generation observatory for ground-based very-high-energy gamma-ray astronomy. It will improve the sensitivity of current ground-based instruments by a factor of five to twenty, depending on the energy, greatly improving both their angular and energy resolutions over four decades in energy (from 20 GeV to 300 TeV). This achievement will be possible by using tens of imaging Cherenkov telescopes of three successive sizes. They will be arranged into two arrays, one per hemisphere, located on the La Palma island (Spain) and in Paranal (Chile). We present here the optimised and final telescope arrays for both CTA sites, as well as their foreseen performance, resulting from the analysis of three different large-scale Monte Carlo productions
Sensitivity of the Cherenkov Telescope Array for probing cosmology and fundamental physics with gamma-ray propagation
The Cherenkov Telescope Array (CTA), the new-generation ground-based observatory for γ astronomy, provides unique capabilities to address significant open questions in astrophysics, cosmology, and fundamental physics. We study some of the salient areas of γ cosmology that can be explored as part of the Key Science Projects of CTA, through simulated observations of active galactic nuclei (AGN) and of their relativistic jets. Observations of AGN with CTA will enable a measurement of γ absorption on the extragalactic background light with a statistical uncertainty below 15% up to a redshift z=2 and to constrain or detect γ halos up to intergalactic-magnetic-field strengths of at least 0.3 pG . Extragalactic observations with CTA also show promising potential to probe physics beyond the Standard Model. The best limits on Lorentz invariance violation from γ astronomy will be improved by a factor of at least two to three. CTA will also probe the parameter space in which axion-like particles could constitute a significant fraction, if not all, of dark matter. We conclude on the synergies between CTA and other upcoming facilities that will foster the growth of γ cosmology
Capital heterogeneity and the decline of the labour share
We investigate the decline of the labour share in a world characterized by increasing heterogeneity of capital assets. Our results show that, over the 1970-2007 period, the decline of the labour share has been mainly driven by Information and Communication Technology (ICT) assets and is mitigated by increasing investments in R&Dbased knowledge assets. Extending to other forms of intangible capital from 1995 onwards, we find that intangible investments related to innovation increase the labour share while those related to the organisation of firms contribute to its decline, particularly for the low and intermediate skilled workers. Our results are robust to an array of econometric issues, namely heterogeneity, cross-sectional dependence, and endogeneit
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