Related papers: Absorption mechanisms in photon induced two-body k…
The invariant mass spectra of the $pp\pi^-$ and $pp$ systems produced in the double charge exchange (DCX) of positively charged pions on photoemulsion are analysed. A pronounced peak is observed in the $pp\pi^-$ invariant mass spectrum,…
In this talk we report on two physical processes, the photoproduction of $\rho$ mesons in nuclei and the $\pi^0 \pi^0$ photoproduction in nuclei at low energies. In the first case the aim is to observe experimentally the theoretically…
A combined analysis of the existing data on the reactions $\gamma p \to p \eta^\prime $ and $pp \to pp\eta^\prime $, based on a relativistic meson exchange model of hadronic interactions, is presented.
The photonuclear reactions 16O(gamma,n)15O and 16O(gamma,p)15N are simultaneously described within a coupled channels framework based on a continuum shell model formulation. The inclusion of Delta(1232) isobar degrees of freedom improves…
Cross sections for the photon-induced particle-emission reactions (gamma,n), (gamma,p), and (gamma,alpha) are given for all natural isotopes from Ti to Bi. The target nuclei are assumed to be in their ground states, except for 180Ta which…
The production of $\eta'$ mesons in the reactions $\gamma p\to p\eta'$ and $pp\to pp\eta'$ is described consistently within a relativistic meson exchange model of hadronic interactions. The photoproduction can be described quite well over…
We calculate the contribution to the nuclear energy density functional which arises from iterated pion-photon exchange between nucleons. In heavy nuclei, this novel charge symmetry breaking interaction leads to an additional binding of each…
Photocatalytic reactions often exhibit fast kinetics and high product selectivity, qualities which are desirable but difficult to achieve simultaneously in thermally driven processes. However, photo-driven mechanisms are poorly understood…
Tagged linearly polarized photons have been used at the Mainz Microtron MAMI for simultaneous measurements of the p(\vec{\gamma},p)\pi^0 and p(\vec{\gamma},\pi^+)n reaction channels to study the \gamma N \to \Delta(1232) transition. The…
We present a nucleon resonance analysis by simultaneously considering all pion- and photon-induced experimental data on the final states gamma N, pi N, 2 pi N, eta N, K Lambda, K Sigma, and omega N for energies from the nucleon mass up to…
We study the reaction mechanism for the correlated $\pi^0\gamma$ emission in the photon induced reaction on the proton target. Since this reaction is studied in the GeV region, we assume that it proceeds through the formation of the vector…
We evaluate the two-photon exchange contribution to the $e N \to e \Delta(1232) \to e \pi N$ process at large momentum transfer with the aim of a precision study of the ratios of electric quadrupole (E2) and Coulomb quadrupole (C2) to the…
The forward inclusive pion double charge exchange reaction, ^{16}O(pi^-,pi^+)X, at T_0 = 0.50 and 0.75 GeV has been studied in the kinematical region where an additional pion production is forbidden by energy-momentum conservation. The…
Relativistic calculations for the quasifree electron scattering process (e, e'p) and the direct knockout contribution to (gamma, p) reactions are presented. The spectroscopic factors determined from the former reaction are used to fix the…
Total and differential cross sections for the reaction gamma p -> pi^o eta p have been measured with the Crystal Ball/TAPS detector using the tagged photon facility at the MAMI C accelerator in Mainz. In the energy range E_gamma=0.95-1.4…
The present status of the theoretical description of electromagnetic reactions on the deuteron above pion threshold is reviewed. Three major topics are considered: (i) retardation effects in $\pi$-meson exchange contributions to…
The photoproduction of 2$\pi^0$ mesons off protons was studied with the Crystal Barrel/TAPS experiment at the electron accelerator ELSA in Bonn. The energy of photons produced in a radiator was tagged in the energy range from 600\,MeV to…
The photodisintegration of $^{16}$O is predicted to be dominated by $E$2 excitation in the vicinity of the $\alpha$-particle threshold. The reaction rates of $^{12}$C($\alpha$,$\gamma$)$^{16}$O are expected to be determined from this…
In this work we investigate the reaction $\gamma p\to\pi^-\Delta^{++}$ in the Reggeized model for $\pi(138)+\rho(775)+a_2(1320)$ exchanges in the $t$-channel. For a convergence of the reaction cross section at high energies the minimal…
A new data set for the helicity-dependent differential cross section of the single-meson photoproduction reaction $\gamma p \to p \pi^{0}$ was obtained for the photon energy interval 150-400 MeV. The experiment was performed at the A2…