Related papers: Complete sets of observables in pseudoscalar-meson…
The exclusive photoproduction of a pair of light mesons is studied within the framework of collinear factorisation. The amplitude factorises into a process-dependent perturbatively calculable hard part, a generalised parton distribution…
An investigation of $\gamma p\to \omega p$ is presented in a constituent quark model approach. The sparse data in the large $t$ region where the resonances dominate is well described within the model, while the diffractive behavior in the…
We describe the formalism to analyze the mathematical ambiguities arising in partial-wave analysis of two spinless mesons produced with a linearly polarized photon beam. We show that partial waves are uniquely defined when all accessible…
Estimates for electroproduction of pseudoscalar mesons at small values of skewness are presented. Cross sections and asymmetries for these processes are calculated within the handbag approach which is based on factorization in hard parton…
We discuss universal signals of consistent models of pseudoscalar mediators for collider searches for Dark Matter. Keeping only the degrees of freedom that can not be decoupled due to consistency conditions, we present a universality class…
We develop polarization observables for the processes $\gamma N\to\pi\pi N$ and $\pi N\to\pi\pi N$, using both a helicity and hybrid helicity-transversity basis. Such observables are crucial if processes that produce final states consisting…
Optimal observables are known to lead to minimal statistical errors on parameters for a given normalised event distribution of a physics reaction. Thereby all statistical correlations are taken into account. Therefore, on the one hand they…
Statistically improved data of total cross sections and of angular distributions for differential cross sections and hyperon recoil polarizations of the reactions \gamma p --> K^+ \Lambda and \gamma p --> K^+ \Sigma^0 have been collected…
Angle-resolved photoemission spectra are calculated microscopically for the two-dimensional attractive Hubbard model. A system of self-consistent T-matrix equations are solved numerically in the real-time domain. The single-particle…
The glob model of Lichard and Van Hove and the modified soft annihilation model (MSAM) of Lichard and Thompson are used as a phenomenological tool for relating results from various experiments on soft photon production in high energy…
A reaction model for $\gamma + p \to V + p$, $V=\rho^0, \phi, J/\psi, \Upsilon$, which exposes the quark-antiquark content of the photon in making the transition $\gamma\to {q} \bar{q} + \mathbb P \to V$, where ${q}$ depends on $V$, and…
We review the last two decades of using photon beams to measure the production of mesons, and in particular the information that can be obtained on the spectrum of light, non-strange baryons. This is a compendium of experimental results,…
Meson photoproduction is an important tool in the study of baryon resonances. The spectrum of broad and overlapping nucleon excitations can be greatly clarified by use of polarization observables. The N* program at Jefferson Lab with the…
Pseudoscalar mesons can be produced and studied in high-energy electron-nucleus scattering. We review and extend our previous analysis of meson production in the nuclear Coulomb field. The $P\rightarrow \gamma \gamma$ decay rates are most…
A gauge-invariant formalism is presented for the practical treatment of photo- and electroproduction of pseudoscalar mesons off nucleons that allows an explicit incorporation of hadronic final-state interactions. The semi-phenomenological…
The scalar mesons f0(1370), f0(1500) and f0(1710) are of interest as there is as yet no consensus of their status, or indeed of the existence of the f0(1370). Radiative decays to rho and omega have been shown to provide effective probes of…
We consider the diffractive photoproduction of $\pi^+\pi^- , K^+K^- , D^+D^-$ meson pairs with high masses and transverse momenta in the framework of the S\"oding model. The total and differential cross sections are calculated for these…
The formal properties of the recently derived set of linearly independent invariant amplitudes for the electromagnetic production of a pseudoscalar particle from a spin-one particle have been further exploited. The crossing properties are…
One of the remaining problems within the standard model is to gain a good understanding of the low energy regime of QCD, where perturbative methods fail. One key towards a better understanding is baryon spectroscopy. Unfortunately, in the…
We provide an analysis of vector meson photoproduction in the channel of the vector meson decaying into a pseudoscalar meson plus a photon, i.e. $V\to P\gamma$. It is shown that non-trivial kinematic correlations arise from the measurement…