A Study of QCD Radiation in VBF Higgs Production with Vincia and Pythia

We discuss and illustrate the properties of several parton-shower algorithms available in Pythia and Vincia, in the context of Higgs production via vector boson fusion (VBF). In particular, the distinctive colour topology of VBF processes allows to define observables sensitive to the coherent radiation pattern of additional jets. We study a set of such observables, using the Vincia sector-antenna shower as our main reference, and contrast it to Pythia's transverse-momentum-ordered DGLAP shower as well as Pythia's dipole-improved shower. We then investigate the robustness of these predictions as successive levels of higher-order perturbative matrix elements are incorporated, including next-to-leading-order matched and tree-level merged calculations, using Powheg Box and Sherpa respectively to generate the hard events.

Axial-Symmetric Diffraction Radiation Antenna with a Very Narrow Funnel-Shaped Directional Diagram

The paper is focused on reliable modeling and analysis of axially symmetric radiators with a very narrow (throat) funnel-shaped radiation pattern. When such a diagram is formed, a wave analogue of Smith–Purcell coherent radiation is realized—the surface wave of a radial dielectric waveguide ‘sweeps out’ with its exponentially decaying part a concentric periodic grating, the fundamental spatial harmonic of which, propagating without attenuation in a direction close to the symmetry axis of the structure, generates a radiation field with the required characteristics.

A synchrotron-based kilowatt-level radiation source for EUV lithography

A compact damping ring with limited circumference of about 160 m is proposed for producing kilowatt-level coherent EUV radiation. The electron bunch in the ring is modulated by a 257nm wavelength laser with the help of the angular dispersion induced micro-bunching method [C. Feng and Z. Zhao, Sci. Rep. 7, 4724 (2017)]. Coherent radiation at 13.5 nm with an average power of about 2.5 kW can be achieved with the state-of-the-art accelerator and laser technologies.

Determination of the crystal lattice parameters based on the fast Fourier transform

In this work, it is shown that the image formed as a result of the passage of coherent radiation through the crystal has certain characteristic features. When the crystal is rotated with respect to the propagation axis of the investigated beam, the formation of the intensity distribution of a complex structure associated with the transformation of the flat image into volumetric was detected at the output. Crystalline plates can be used to form the distribution of a continuous flat light field in the implementation of a real 3D scene, which can provide a three-dimensional image on a television screen, as well as on a computer monitor screen. It can also be used in billboards. The three-dimensional image obtained in this way can be observed directly with the eyes of a person (without using special glasses. Thus, the information capacity of the image on the screen increases, and the perception of the picture approaches real conditions.

Vacuum ultraviolet coherent undulator radiation from attosecond electron bunches

Attosecond duration relativistic electron bunches travelling through an undulator can generate brilliant coherent radiation in the visible to vacuum ultraviolet spectral range. We present comprehensive numerical simulations to study the properties of coherent emission for a wide range of electron energies and bunch durations, including space-charge effects. These demonstrate that electron bunches with r.m.s. duration of 50 as, nominal charge of 0.1 pC and energy range of 100–250 MeV produce $$10^9$$ 10 9 coherent photons per pulse in the 100–600 nm wavelength range. We show that this can be enhanced substantially by self-compressing negatively chirped 100 pC bunches in the undulator to produce $$10^{14}$$ 10 14 coherent photons with pulse duration of 0.5–3 fs.