A Time-domain Double Diffraction for Non-perfectly Conducting Wedges

A time-domain (TD) double diffraction solution is proposed with the source illumination for one or both sides of non-perfectly conducting wedges. The frequency domain redefined reflection angles as well as modified reflection coefficients are used in the different angular region of wedges for developing TD double diffraction. The accuracy of the proposed model is confirmed with IFFT- FD solution. Finally, the table of computational efficiency has been given for both the methods (TD and IFFT-FD) for hard polarization.

Pomeron-Pomeron Scattering

The central exclusive diffractive (CED) production of meson resonances potentially is a factory producing new particles, in particular, a glueball. The produced resonances lie on trajectories with vacuum quantum numbers, essentially on the pomeron trajectory. A tower of resonance recurrences, the production cross-section, and the resonances widths are predicted. A new feature is the form of a non-linear pomeron trajectory, producing resonances (glueballs) with increasing widths. At LHC energies, in the nearly forward direction, the t-channel both in elastic, single, or double diffraction dissociations, as well as in CED, is dominated by the pomeron exchange (the role of secondary trajectories is negligible, however a small contribution from the odderon may be present).

Structure of crystallized particles in sputter-deposited amorphous germanium films

Pristine thin films of amorphous Ge prepared by sputtering are unstable and form coarse crystalline particles of 100 nm in size upon crystallization by electron irradiation. These crystalline particles exhibit unusual diffraction patterns that cannot be understood from the diamond cubic structure. The structure has previously been assumed to be a metastable hexagonal form. In the present work, the structure of the coarse crystalline particles has been analysed in detail by transmission electron microscopy, considering the possibility that those diffraction patterns might occur with the diamond cubic structure if the particle consists of thin twin layers. By high-resolution lattice imaging the particles have been shown to be of the diamond cubic structure containing a high density of twins and stacking faults parallel to {111}. With such defects, diffraction patterns can be complex because of the following effects: superposition of two or more diffraction patterns of the same structure but of different orientations, double diffraction through twin crystals, and streaks parallel to the thin crystal which give rise to extra diffraction spots. It is found that diffraction patterns taken from various orientations can be explained in terms of these effects.