Related papers: Pion Compton Scattering in Perturbative QCD
Inspired by the relation between the hadronic decay of the tau lepton and the electron-positron annihilation into hadrons, we derive new tests of perturbative QCD. We design a set of commensurate scale relations to test the self-consistency…
Based on parametric reasoning, we provide a simple dynamical picture of how a perturbative parton cascade, in interaction with a QCD medium, fills phase space as a function of time.
We present the first attempt to extract the scalar dipole dynamical polarizabilities from proton real Compton scattering data below pion-production threshold. The theoretical framework combines dispersion relations technique, low-energy…
We present a calculation of the virtual Compton scattering amplitude for $\gamma^\ast+\pi\to \gamma+\pi$ in the framework of chiral perturbation theory at ${\cal O}(p^4)$. We explicitly derive expressions for generalized electromagnetic…
The Real Compton Scattering in ultraperipheral $pPb$ collisions at RHIC and LHC energies is investigated and predictions for the squared transverse momentum ($t$) and rapidity ($Y$) distributions are presented. The scattering amplitude is…
Compton scattering off the proton in the third resonance region is analyzed for the first time, owing to the full combined analysis of pion- and photo-induced reactions in a coupled-channel effective Lagrangian model with K-matrix…
The pion structure function is investigated in a simple model, where the pion and its constituent quark fields are coupled through the simplest pseudoscalar coupling. The imaginary part of the forward gamma* pi -> gamma* pi scattering…
Excited hadrons are seen as resonances in the scattering of lighter stable hadrons like $\pi$, $K$ and $\eta$. Many decay into multiple final states necessitating coupled-channel analyses. Recently it has become possible to obtain…
The electromagnetic polarizabilities of the nucleon are fundamental nucleon-structure observables that characterize its response to external electromagnetic fields. The neutron polarizabilities can be accessed from Compton-scattering data…
We study the amplitude of deeply virtual Compton scattering in next-to-leading order of perturbation theory including the two-loop evolution effects for different sets of skewed parton distributions (SPDs). It turns out that in the minimal…
The pion-polarizability functions are structure functions of pion-Compton scattering. They can be assessed in high-energy pion-nucleus bremsstrahlung reactions, $\pi^- +A\to\pi^- +\gamma +A$. We present numerical expectations for…
In the scaling regime, amplitudes for backward virtual Compton scattering and hadron annihilation into two photons depend on structure functions that describe the hadron-photon transition at the partonic level. We construct simple…
We evaluate a number of new instanton-induced phenomena in QCD, starting with static dipole-dipole potentials, and proceeding to quark-quark and dipole-dipole scattering at high energy. We use a non-perturbative formulation of the…
As a guideline for future experiments to extract the four (leading) spin polarizabilities of the nucleon, we have constructed the forward amplitude for polarized Compton scattering by dispersion integrals. These integrals have been…
The classical scattering of spinning objects is well described by the spinor-helicity formalism for heavy particles. Using these variables, we derive spurious-pole-free, all-spin opposite-helicity Compton amplitudes (factorizing on physical…
We review the current state of knowledge of the nucleon polarizabilities and of their role in nucleon Compton scattering and in hydrogen spectrum. We discuss the basic concepts, the recent lattice QCD calculations and advances in chiral…
Measurements of jet, prompt photon, high-pT hadron and heavy quark production in photon-induced processes provide tests of QCD and are sensitive to the photon parton densities. A review of the latest experimental results in photon-photon…
We analyse deeply-virtual Compton scattering on a proton target, gamma* P -> P' gamma in the backward region and in the scaling regime. We define the transition distribution amplitudes which describe the proton to photon transition.…
A dipole picture of high energy scattering is developed in the 2+1 dimensional QCD, following Mueller. A generalized integral equation for the dipole density with a given separation and center of mass position is derived, and meson-meson…
Using the Kirschner-Lipatov equation as a basis, we study high energy elastic quark-quark amplitudes, which correspond to secondary Reggeons and pion exchange in the double-logarithmic approximation of perturbative QCD.