Astroparticle physics is undergoing a profound transformation, due to a series of extraordinary new results, such as the discovery of high-energy cosmic neutrinos with IceCube, the direct detection of gravitational waves with LIGO and Virgo, and many others. This white paper is the result of a collaborative effort that involved hundreds of theoretical astroparticle physicists and cosmologists, under the coordination of the European Consortium for Astroparticle Theory (EuCAPT). Addressed to the whole astroparticle physics community, it explores upcoming theoretical opportunities and challenges for our field of research, with particular emphasis on the possible synergies among different subfields, and the prospects for solving the most fundamental open questions with multi-messenger observations.

This report summarises the physics opportunities in the search and study of physics beyond the Standard Model at a 100 TeV pp collider.

In response to the 2013 Update of the European Strategy for Particle Physics (EPPSU), the Future Circular Collider (FCC) study was launched as a world-wide international collaboration hosted by CERN. The FCC study covered an energy-frontier hadron collider (FCC-hh), a highest-luminosity high-energy lepton collider (FCC-ee), the corresponding 100km tunnel infrastructure, as well as the physics opportunities of these two colliders, and a high-energy LHC, based on FCC-hh technology. This document constitutes the third volume of the FCC Conceptual Design Report, devoted to the hadron collider FCC-hh. It summarizes the FCC-hh physics discovery opportunities, presents the FCC-hh accelerator design, performance reach, and staged operation plan, discusses the underlying technologies, the civil engineering and technical infrastructure, and also sketches a possible implementation. Combining ingredients from the Large Hadron Collider (LHC), the high-luminosity LHC upgrade and adding novel technologies and approaches, the FCC-hh design aims at significantly extending the energy frontier to 100TeV. Its unprecedented centre of-mass collision energy will make the FCC-hh a unique instrument to explore physics beyond the Standard Model, offering great direct sensitivity to new physics and discoveries.

In this paper, we constrain CP violation in the Higgs sector using the measured signal strengths in the various Higgs search channels. To this end, we introduce a general parametrization for a resonance which is an admixture of a CP-even Higgs-like state and a CP-odd scalar. By performing a fit to the available data from the Tevatron and LHC experiments, one obtains constraints on the mixing angle and the couplings of the resonance to Standard Model fields. Depending on the couplings, sizable mixing angles are still compatible with the data, but small mixing is in general preferred by the fit. In particular, we find that a pure CP-odd state is disfavored by the current data at the 3 sigma level. Additionally, we consider a mixed fermiophobic resonance and a model with two degenerate mixed resonances and find that both scenarios can successfully fit the data within current errors. Finally, we estimate that the mixing angle can be constrained to alpha < 1: 1 (0.7) in the full 8 TeV (14 TeV) run of the LHC. DOI: 10.1103/PhysRevD.87.055014

Based on a recent idea by Krohn and Yavin, we construct a little Higgs model with an internal parity that is not broken by anomalous Wess-Zumino-Witten terms. The model is a modification of the "minimal moose" models by Arkani-Hamed et al. and Cheng and Low. The new parity prevents large corrections to oblique electroweak parameters and leads to a viable dark matter candidate. It is shown how the complete Standard Model particle content, including quarks and leptons together with their Yukawa couplings, can be implemented. Successful electroweak symmetry breaking and consistency with electroweak precision constraints is achieved for natural parameters choices. A rich spectrum of new particles is predicted at the TeV scale, some of which have sizable production cross sections and striking decay signatures at the LHC.

We analyze the collider signals of composite scalars that emerge in certain little Higgs models and models of vectorlike confinement. Similar to the decay of the pion into photon pairs, these scalars mainly decay through anomaly-induced interactions into electroweak gauge bosons, leading to a distinct signal with three or more photons in the final state. We study the standard model backgrounds for these signals, and find that the LHC can discover these models over a large range of parameter space with 30 fb−1 at 14 TeV. An early discovery at the current 7 TeV run is possible in some regions of parameter space. We also discuss possibilities to measure the spin of the particles in the γγ and Zγ decay channels.

In the popular littlest Higgs model, T-parity can be broken by Wess-Zumino-Witten (WZW) terms induced by a strongly coupled UV completion. On the other hand, certain models with multiple scalar multiplets (called moose models) permit the implementation of T-parity such that it is not broken by the WZW terms. Here we present a concrete realization of such a. model, and discuss the phenomenology at the Large Hadron Collider, in particular differences with respect to the littlest Higgs model.

A comparison of microcompression and microtensile methods to study mechanical properties of electrodeposited nanocrystalline (nc) nickel has been performed. Microtensile tests that probe a volume of more than 2 × 106 μm3 show reasonable agreement with results from microcompression tests that probe much smaller volumes down to a few μm3. Differences between the two uniaxial techniques are discussed in terms of measurements errors, probed volume and surface effects, strain rate, and influence of stress state. Uniaxial solicitation in compression mode revealed several advantages for studying stress–strain properties.

Cr-O-N coatings were produced by reactive cathodic arc deposition at different N-2/O-2 flow ratios onto cemented carbide substrates. The structure, and mechanical properties of the coatings depend strongly on their oxygen content. The increase of the oxygen content leads to a decrease of the mean crystallite size of the nanocrystalline cubic (B1 structure) Cr-O-N phase and to an enhancement of the (002) preferred orientation. At O/(O+N) ratios > 0.7 the coatings crystallize in the rhombohedral Cr2O3 structure. The morphology of the samples, as studied by scanning electron microscopy (SEM), is columnar. The hardness of the coatings increases up to a maximal value of 28 GPa with increasing the oxygen content. Higher oxygen contents lower the hardness of the coatings. X-ray powder diffraction (XRD) studies were performed in situ at high temperatures, in vacuum and in air. The crystallite growth at elevated temperatures, both in vacuum and in air, is hindered significantly by the presence of oxygen in the coatings. The Cr-O-N coatings with the Ell structure, annealed in vacuum and in air, provide an improved thermal stability, with no evidence of oxidation or formation of the Cr2N phase up to 900 degrees C. (C) 2008 Elsevier B.V. All rights reserved.

Topography measurements and roughness calculations for different rough surfaces (Rugotest surface comparator and thermally sprayed coatings) are presented. The surfaces are measured with a novel quantitative topography measurement technique based on optical stereomicroscopy and a comparison is made with established scanning stylus and optical profilometers. The results show that for most cases the different methods yield similar results. Stereomicroscopy is therefore a valuable method for topographical investigations in both quality control and research. On the other hand, the method based on optical microscopy demands a careful optimization of the experimental settings like the magnification and the illumination to achieve satisfactory results.

In this paper we consider the effects of the T-parity violating anomalous Wess-Zumino-Witten term in the Littlest Higgs model. Apart from tree level processes, the loop induced decays of the heavy mirror particles into light standard model fermions lead to a new and rich phenomenology in particular at breaking scales f below 1 TeV. Various processes are calculated and their signatures at present and future colliders are discussed. As a by product we find an alternative production mechanism for the Higgs boson.

Composition, structure and morphology of Cr–Si–N coatings deposited by cathodic arc ion-plating on cemented carbide substrates were studied. A systematic variation of the deposition parameters resulted in relative Si atomic concentrations Si/(Cr + Si) within 0 and 15at.%, which affect significantly the properties of the coatings, their phase stability and oxidation resistance. All Cr–Si–N coatings consist of nanocrystalline CrN grains with diminishing crystallite sizes at increased Si content. The microstructure of the samples, observed by scanning electron microscopy, is columnar for the coatings with low Si concentration, and becomes denser for specimens with higher Si content. The hardness and Young's modulus of the coatings increase with increasing Si concentration up to a maximum value of 26GPa and 430GPa, respectively, for the Cr0.94Si0.06N coatings, followed by a progressive decrease. X-ray powder diffraction studies were performed in situ up to 1000°C in vacuum and in air. Annealing in vacuum resulted in the decomposition of CrN into Cr2N and N2 and the subsequent oxidation. The annealing performed in air proved an excellent oxidation resistance of the coatings, which strongly depends on their composition and morphology. The best oxidation resistance was obtained for the hardest samples with intermediate Si concentration, for which the formation of Cr2O3 has not been observed even at 1000°C. Recrystallization, which occurs at elevated temperatures both in vacuum and in the air, becomes significant above approximately 800°C.

There is increasing interest in using sharp cube-corner indenters in nanoindentation experiments to study plastic properties. In combination with finite element methods, it is, for example, possible to extract stress–strain curves from load–displacement curves measured with differently shaped pyramidal indenters. Another example is the fracture toughness of coatings, which can be studied using cracks produced during indentation with cube-corner tips. We have carried out indentation experiments with Berkovich and cube-corner indenters on eight different materials with different mechanical properties. To gain information about the formation of pile-up and cracks, indentation experiments with cube-corner indenter were performed inside a scanning electron microscope (SEM) using a custom-built SEM-microindenter. The results show that reliable hardness and modulus values can be measured using cube-corner indenters. However, the fit range of the unloading curve has a much bigger influence on the results for the cube-corner than for the Berkovich tip. The unloading curves of a cube-corner measurement should, therefore, be carefully inspected to determine the region of smooth curvature, and the unloading fit range chosen warily. Comparison of the modulus results shows that there is no significant difference between cube-corner and Berkovich measurements. Also for hardness, no fundamental difference is observed for most of the investigated materials. Exceptions are materials, such as silicon nitride, cemented carbide or glassy carbon, where a clear difference to the hardness reference value has been observed although the modulus difference is not pronounced.

Lead zirconate titanate (PZT) thin films have a large application potential in microelectronic devices, memory applications and microelectromechanical systems. Reactive sputtering of a single metallic target in a pulsed DC mode is a promising approach for a fast and cost‐efficient deposition of thin PZT films on an industrial scale. However, for efficient optimization of the process parameters, it is necessary to have access to a rapid tool for chemical depth profiling. We will show in this paper that glow‐discharge optical emission spectroscopy (GD‐OES) is capable of yielding fast and reliable information about the PZT thin film composition. A novel pulsed mode of GD‐OES was applied to bulk PZT samples (for calibrations purposes) and to thin PZT coatings. The influence of different parameters on this pulsed mode will be discussed. Using pulsed GD‐OES we could successfully measure the composition of our PZT thin films and so optimize the deposition process. Copyright © 2006 John Wiley & Sons, Ltd.

Fiber-reinforced composites (FRCs) show great promise as long-term restorative materials in dentistry and medicine. Recent evidence indicates that these materials degrade in vivo, but the mechanisms are unclear. The objective of this study was to investigate mechanisms of deterioration of glass fiber-polymer matrix bond strengths in dental fiber-reinforced composites during hydrothermal and mechanical aging. Conventional three-point bending tests on dental FRCs were used to assess flexural strengths and moduli. Micro push-out tests were used to measure glass fiber-polymer matrix bond strengths, and nanoindentation tests were used to determine the modulus of elasticity of fiber and polymer matrix phases separately. Bar-shaped specimens of FRCs (EverStick, StickTech, and Vectris Pontic, Ivoclar-Vivadent) were either stored at room temperature, in water (37 and 100 degrees C) or subjected to ageing (10(6) cycles, load: 49 N), then tested by three-point bending. Thin slices were prepared for micro push-out and nanoindentation tests. The ultimate flexural strengths of both FRCs were significantly reduced after aging (p < 0.05). Both water storage and mechanical loading reduced the interfacial bond strengths of glass fibers to polymer matrices. Nanoindentation tests revealed a slight reduction in the elastic modulus of the EverStick and Vectris Pontic polymer matrix after water storage. Mechanical properties of FRC materials degrade primarily by a loss of interfacial bond strength between the glass and resin phases. This degradation is detectable by micro push-out and nanoindentation methods.

TiO2 films with uniform thickness were electrolytically deposited on AISI 316L stainless steel and Ti6Al4V substrates for potential use as color coded biocompatible coatings on biomedical implants. Deposition occurred via a peroxoprecursor method from solutions containing TiCl4 and H2O2. By optimizing electrolyte formulation and deposition parameters, thin stoichiometric titania films with almost uniform thickness-dependent interference colors, similar as known from the color anodization processes of Ti-alloys, were obtained. Crack-free films were found up to 140 nm on AISI 316L and up to 190 nm on Ti6Al4V substrates. After thermal annealing at 450 °C of as-deposited amorphous peroxotitanium hydrate films, Raman and transmission electron microscopy showed highly stoichiometric, nanocrystalline anatase films. Chemical depth profiling was performed by glow-discharge optical emission spectrometry (GD-OES), showing clearly a densification and loss of water during annealing. On AISI 316L, GD-OES revealed stoichiometric TiO2 films containing a small Fe (3–4 at.%) and Cr (1 at.%) contamination due to thermal diffusion from the substrate. On Ti6Al4V, the comparison between electrolytic TiO2 films and color-anodization in different sulfuric and phosphoric acid containing electrolytes showed significant higher purity of electrolytic films, absent of V, Al, S, P contaminations as they were found in anodic oxides (4–6 at.% Al, 1–2 at.% V), especially V and S being problematic in biomedical applications. Annealing greatly increased the mechanical properties of the green films. A nano-hardness of 5.5–6.6 GPa, elastic modules close to substrate modules, excellent adhesion and very ductile behavior were found from nanoindentation and scratch tests. Based on thickness uniformity, high purity and good mechanical properties, electrolytic TiO2 films are not only attractive as biocompatible colored coatings on non-anodizable biomedical alloys such as AISI 316L and CoCrMo, but also for Ti-alloys that are anodized for protective as well as coding reasons prior to implantation.

The Modulus of Elasticity (MOE) and the hardness of fibril reinforced hydroxypropyl cellulose films were determined by nanoindentation. In addition, the fibril alignment in the composites was analysed by Transmission Electron Microscopy (TEM) and Atomic Force Microscopy (AFM). The results show that the formation of fibril networks is of great importance for the mechanical properties of the nanocomposites.

The limitations of conventional coatings due to inferior hardness or poor oxidation stability can be overcome by nanocomposite hard coatings such as nc-TiN/a-SiNx, which consists of nanocrystalline TiN and a non-crystalline tissue phase of SiNx which are mutually immiscible. The properties of nanocomposite coatings, especially their increased hardness, can be explained by their nanostructure, which leads to a maximum hardness at typically 80 atomic percent of the crystalline phase. We show that enhanced hardness can only be attained when the silicon nitride phase is sufficiently nitrided. The accurate and reliable measurement of the hardness and elastic modulus requires the use of appropriate nanoindentation equipment and a careful tip correction with periodical validation. It is shown that for a correct hardness determination of a few microns thick nanocomposite coatings, an indentation depth of 100 nm is sufficient. The maximum hardness of our nc-TiN/a-SiNx coatings deposited by a hybrid UBM/arc-PVD process is about 40 GPa. This value represents a global hardness value, due to the nanocomposite structure there may be a local hardness variation of about +/- 10%.

Reactive sputtering of a single metallic target in a pulsed DC mode is a promising approach for a fast and cost-efficient deposition of thin lead zirconate titanate (PZT) films on an industrial scale. Rapid depth profiling of the coatings is necessary for an efficient optimization of the process parameters. We demonstrate in this paper that glow-discharge optical emission spectroscopy is a valuable instrument meeting these requirements. The results obtained on several coatings which have been thermally treated in various ways indicate basically a high uniformity over the whole coating thickness, with the exception of Pb-enrichment at the surface and at the interface. This is in agreement with results obtained by other techniques reported in the literature. The mechanical properties of our PZT coatings as determined by nanoindentation showed reduced values for the hardness which could be explained by the structural and compositional data of the films.