We derive expressions for strangeness–changing scalar form factors, which incorporate known theoretical constraints both at low and high energies. Their leading behaviour in the limit of a large number of colours is calculated from the resonance chiral Lagrangian. A set of short-distance constraints on the scalar resonance couplings is obtained, imposing the form factors to vanish at infinite m...

The nucleon elastic form factors are of fundamental interest, provide a unique testing ground for QCD motivated models of nucleon structure and are of critical importance to our understanding of the electromagnetic properties of nuclei. I review the recent experimental effort to measure the nucleon elastic form factors.

We reformulate the radiosity equation in terms of the radiance of light rays rather than in terms of pairs of surface facets, and develop an algorithm for solving it using a coordinate evolution on the set of light rays in a scene. There are two key advantages to the new formulation. First, coordinate evolution is naturally embedded in a massively parallel SIMD architecture. The result is an al...

Hadronic elastic and transition form factors are used to describe elastic nucleon-nucleon and pion-nucleon scattering, as well as diffractive excitation of nucleon resonances in an optical model. Very good quantitative agreement with available experimental results is obtained.

Electromagnetic form factors of the nucleon and its excitations (baryon resonances) provide a powerful tool to investigate the structure of the nucleon. These form factors can be measured in electroproduction as a function of the four-momentum squared q = −Q of the virtual photon. In this contribution we present a simultaneous study of the elastic form factors of the nucleon and the transition ...

We study the uncertainties of Sudakov form factors as the basis for parton shower evolution in Monte Carlo event generators. We discuss the particular cases of systematic uncertainties of parton distribution functions and scale uncertainties.

Recently we have reconsidered the quantization of relativistic field theories on a Lorentz-invariant surface of the form xμx μ = τ [1]. With this choice of the quantization surface all components of the 4-momentum operator become interaction dependent, whereas the generators of Lorentz transformations stay free of interactions – a feature characteristic for Dirac’s “point form” of relativistic ...