Related papers: Including Pions
Two-particle two-hole contributions to electromagnetic response functions are computed in a fully relativistic Fermi gas model. All one-pion exchange diagrams that contribute to the scattering amplitude in perturbation theory are…
Distorted-wave methods are used to remove the effects of one- and two-pion exchange up to order Q^3 from the empirical 1P1 phase shift. The one divergence that arises can be renormalised using an order-Q^2 counterterm which is provided by…
We study the nucleon-nucleon interaction up to next-to-next-to-leading order using time-ordered perturbation theory in the framework of manifestly Lorentz-invariant chiral effective field theory. We present the two-pion exchange…
Effective field theory techniques are used to describe the interaction of heavy hadrons in a model independent way. Predictability is obtained by exploiting the symmetries of QCD. Heavy hadron chiral perturbation theory is reviewed and used…
We study coherent pion production in neutrino-nucleus scattering in the energy region relevant to the recent neutrino oscillation experiments. Our approach is based on the combined use of the Sato-Lee model and the Delta-hole model. Our…
A simple but useful guide for understanding the structure of light nuclei is presented. It is based on counting the number of interacting pairs in different spin-isospin (S,T) states for a given spatial symmetry, and estimating the overall…
We give a brief review on the important role of the pion-exchange interaction characterized by the strong tensor force. In order to illustrate the role of the pion, we have proposed a new mean field theory with the charge and parity mixing,…
The S-matrix approach is used to calculate charged as well as neutral pion production reactions from NN scattering, with the same set of underlying processes and interactions. The chiral perturbation theory piN scattering amplitude is used.…
We use our model for neutrino pion production on the nucleon to study pion production on a nucleus. The model is conveniently modified to include in-medium corrections and its validity is extended up to 2 GeV neutrino energies by 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…
The properties of low-energy neutron-proton systems are studied in an effective field theory where only nucleons figure as relevant degrees of freedom. With a finite momentum cut-off regularization scheme, we show that the large scattering…
Pion exchange is the central ingredient to nucleon-nucleon interactions used in nuclear structure calculations, and one pion exchange (OPE) enters at leading order in chiral effective field theory. In the $^{2S+1}L_J={^1S_0}$ partial wave,…
In this work the elastic scattering of two nucleons is calculated in chiral effective field theory at next-to-leading order taking into account the coupled N$\Delta$-, $\Delta$N- and $\Delta\Delta$-channels. To solve the coupled channel…
The standard way to demonstrate the relevance of chiral symmetry for the NN interaction is to consider higher partial waves of NN scattering which are controlled entirely by chiral pion-exchanges (since contacts vanish). However, in…
It is argued that the fine-tuning due to the unnaturally large, generalized effective range in the 1S0 channel of NN scattering must be incorporated in order for one to obtain satisfactory convergence for chiral effective field theory.…
Recently we have proposed a new cut-off scheme for pion loop integrals in the two-pion exchange potential. This method allows for a consistent implementation of constraints from pion-nucleon scattering and has been successfully applied to…
Elastic scattering of pions from finite nuclei is investigated utilizing a contemporary, momentum--space first--order optical potential combined with microscopic estimates of second--order corrections. The calculation of the first--order…
The pion and nucleon mass differences generate a very pronounced cusp in the photoproduction reaction of a single pion on the nucleon. A nonrelativistic effective field theory to describe this reaction is constructed. The approach is…
Neutron-deuteron scattering in the context of ``pion-less'' Effective Field Theory at very low energies is investigated to next-to-next-to-leading order. Convergence is improved by fitting the two-nucleon contact interactions to the tail of…
We show how to attach an external photon to a system of three strongly interacting nucleons described by three-body scattering equations. Our method involves the idea of gauging the scattering equations themselves, and results in…