相关论文: Pion-Nucleon Distribution Amplitudes
We consider two-nucleon scattering close to threshold. Partial-wave amplitudes are obtained by an analytic extrapolation of subthreshold reaction amplitudes calculated in a relativistic formulation of chiral perturbation theory. The…
We review the major progress of the past decade concerning our understanding of the nucleon-nucleon interaction. The focus is on the low-energy region (below pion production threshold), but a brief outlook towards higher energies is also…
A scenario is investigated in which the leading-twist pion distribution amplitude phi_pi (x) is approximated by the pion decay constant f_pi for all essential values of the light-cone fraction x. A model for the light-front wave function…
The generalized parton distributions and the generalized distribution amplitudes give access to a deeper understanding of the quark and gluon content of hadrons. In this short review, we select some new developments of their interesting…
A short review of the present knowledge of the nucleons distribution in nuclei is given. A proposal is made about a possible measurements of the neutron distribution through polarized electron scattering off nuclei.
Many approaches to nucleon-nucleus elastic and inelastic scattering are based on the use of the free-space nucleon-nucleon transition amplitude. In calculations where the full spin-dependence of this amplitude is needed, its use is more…
We discuss what can be learned about the shape of the pion distribution amplitude from the form factor for gamma* gamma(*) to pi transitions.
Using a self-consistent delta-hole model the pion propagation in isospin asymmetric nuclear matter is studied. In neutron-rich matter, corresponding to heavy nuclei, a significant difference in positive and negative pion light-cone…
Pion photoproduction amplitudes are calculated from a set of equations that have been derived by coupling an external photon to all places in a dressed pion-nucleon vertex. The calculation is consistent with gauge invariance, charge…
To study cross sections and polarization asymmetries for the processes $e p \to e n \pi^+$ and $e p \to e p \pi^0$ in the backward region, we develop a flexible phenomenological model for nucleon-to-pion transition distribution amplitudes…
I review the current status of global analysis of nuclear parton distributions and discuss some near-future prospects. I also advocate proton-nucleus (p-$A$) measurements at the LHC with $A\ll 208$ from the viewpoint of nuclear parton…
The extraction of the isovector s-wave pi N amplitude from pionic atoms is studied with special emphasis on uncertainties and their dependence on the assumptions made regarding the neutron density distributions in nuclei and on the size of…
A chiral pion-nucleon amplitude supplemented by the HJS subthreshold coefficients is used to calculate the the long range part of the two-pion exchange nucleon-nucleon potential. In our expressions the HJS coefficients factor out, allowing…
We study pion--nucleon scattering with a chiral lagrangian of pions, nucleons, and $\Delta$-isobars. The scattering amplitude is evaluated to one-loop $Q^3$ order, where $Q$ is a generic small momentum, using a new approach which is…
We give an overview of the theory for generalized parton distributions. Topics covered are their general properties and physical interpretation, the possibility to explore the three-dimensional structure of hadrons at parton level, their…
Generalized Parton Distributions of the pion are evaluated in chiral quark models with the help of double distributions. As a result the polynomiality conditions are automatically satisfied. In addition, positivity constraints, proper…
We derive an explicit and model-independent representation for the skewed quark distribution of the pion in the limit of large momentum transfer. Our result is expressed in terms of the conventional pion distribution amplitudes and complies…
A general expression for the $\pi -N$ and $\pi-\Delta $ scattering lengths is derived in the framework of a microscopic calculation. Annihilation, negative energy wave-functions and spontaneous chiral symmetry are included consistently. The…
We present an extensive study on generalized parton distributions of pions. In particular, we present the results for the pion-photon transition distribution amplitudes in the Nambu - Jona-Lasinio model. We discuss the phenomenology of such…
Recent experimental results on the proton and neutron polarizabilities are examined from the point of view of backward dispersion relations. Results are found to be in reasonable agreement with the measured values. A rigorous relationship…