Related papers: Novel soft-photon analysis of $pp\gamma$ below pio…
We discuss diffractive processes in proton-proton collisions at small momentum transfers without and with photon radiation. We consider the soft exclusive reactions $pp \to pp$, $p\bar{p} \to p\bar{p}$, and $pp \to pp \gamma$ within the…
A dynamical model based on effective Lagrangians is proposed to describe the bremsstrahlung reaction $ \pi N \to \pi N \gamma$ at low energies. The $\Delta(1232)$ degrees of freedom are incorporated in a way consistent with both,…
We discuss the reactions $\pi p \to \pi p$ and $\pi p \to \pi p \gamma$ from a general quantum field theory (QFT) point of view, describing these reactions in QCD and lowest relevant order of electromagnetism. We consider the pion-proton…
We prove new soft pion theorem for the near threshold pion production by a hard electromagnetic probe. This theorem relates various near threshold pion production amplitudes to the nucleon distribution amplitudes. The new soft pion theorem…
The emission of soft radiation provides a fundamental probe of the consistency of the underlying quantum field theory. Correspondingly, the measurement of the soft photon bremsstrahlung, such as the one proposed with the planned future…
We investigate the photon emission in pion-pion and pion-proton scattering in the soft-photon limit where the photon energy $\omega \to 0$. The expansions of the $\pi^{-} \pi^{0} \to \pi^{-} \pi^{0} \gamma$ and the $\pi^{\pm} p \to…
Certain soft photon amplitudes which have been recently suggested as alternatives to the usual Low form of the soft photon approximation are studied and it is demonstrated that problems exist in their relation to the corresponding…
Photon energy spectra up to the kinematic limit have been measured in 190 MeV proton reactions with light and heavy nuclei to investigate the influence of the multiple-scattering process on the photon production. Relative to the predictions…
A dynamical model based on effective Lagrangians is proposed to describe the bremsstrahlung reaction $ \pi N \to \pi N \gamma$ at low energies. The $\Delta(1232)$ degrees of freedom are incorporated in a way consistent with both,…
For nearly fifty years theoretical and experimental efforts in nucleon-nucleon bremsstrahlung (NN$\gamma$) have been devoted to measuring off-shell amplitudes and distinguishing among various NN potentials on the basis of their off-shell…
We investigate the possibility that the process of $\rho^{0}$-meson photoproduction on proton, $\gamma+p\to p+\rho^{0}$, in the near threshold region $E_{\gamma}< 2$ GeV, can be considered in the framework of model with $\pi$-, $\sigma$-…
A parameter-free and relativistic extension of the RuhrPot meson-baryon model is used to define the dominant isoscalar meson-exchange currents. We compute pp-bremsstrahlung observables below the $\pi-$production threshold using a…
The proton-proton bremsstrahlung is investigated within a coupled-channel model with the $\Delta$ degree of freedom. The model is consistent with the $NN$ scattering up to 1 GeV and the $\gamma N\Delta$ vertex determined in the study of…
Nucleon-nucleon bremsstrahlung has long been considered a way of getting information about the off-shell nucleon-nucleon amplitude which would allow one to distinguish among nucleon-nucleon potentials based on their off-shell properties.…
We give predictions for the partial wave amplitudes of pion photoproduction near threshold by means of dispersion relations at fixed t. The free parameters of this approach are determined by a fit to experimental data in the energy range…
We show that the data on $\gamma p$ and $\gamma\gamma$ interactions can be derived from the $pp$ and $\bar p p$ forward scattering amplitudes using vector meson dominance and the additive quark model. The nucleon-nucleon data are…
"Subthreshold pions" and so-called "hard photons" are two important channels for producing less than 1 GeV $\gamma$-rays and $e^\pm$ pairs from nuclear collisions with energy per nucleon below the $\pi$-meson production threshold. I use…
Pion electro- and photoproduction off the nucleon close to threshold is studied in covariant baryon chiral perturbation theory at O($p^3$) in the extended-on-mass-shell scheme, with the explicit inclusion of the $\Delta(1232)$ resonance.…
The Argonne National Laboratory-Osaka University (ANL-Osaka) amplitudes (http://www.phy.anl.gov/theory/research/anl-osaka-pwa/) are applied to study pion photo-production reactions on the deuteron target. Within the multiple scattering…
A relativistic and manifestly gauge-invariant soft-photon amplitude, which is consistent with the soft-photon theorem and satisfies the Pauli Principle, is derived for the proton-proton bremsstrahlung process. This soft-photon amplitude is…