相关论文: Pion production reactions in nucleon-nucleon colli…
A brief overview on recent model calculations for near threshold pion production in nucleon-nucleon collisions is given. Results from our own investigations of the reactions $pp \rightarrow pp\pi ^0$ and $pn \rightarrow d\pi^0$ are…
The large variety of experimental data around the pion-production threshold are compared with a meson-exchange isobar model which includes the pion-nucleon interaction in s-- and p-waves. Theoretical results obtained with two different NN…
We evaluate the threshold matrix-element for the reaction $pp \to pp\pi^0$ in a fully relativistic Feynman diagrammatic approach. We employ a simple effective range approximation to take care of the S-wave $pp$ final-state interaction. The…
This work discusses the approximations frequently used to calculate the contribution to pion production in proton-proton scattering near threshold from irreducible pion re-scattering. The reference result is obtained from the quantum…
We investigate p-wave pion production in nucleon-nucleon collisions up to next-to-next-to-leading order in chiral effective field theory. In particular, we show that it is possible to describe simultaneously the p-wave amplitudes in the…
Pion production at threshold from nucleon-deuteron collisions is considered, with reference to the outgoing channel where the three-nucleon system is bound. The available experimental data are compared with calculations using accurate…
The total cross section for the near threshold eta production in proton-proton collisions has been investigated with the assumption that the production mechanism is due to the emission of a meson x (pi, eta, sigma) from one of the nucleons…
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.…
In order to establish links between p-wave pion production in nucleon-nucleon collisions and low energy three-nucleon scattering, an extensive programme of experiments on pion production is currently underway at COSY-ANKE. The final proton…
The S-matrix approach is applied to charged and neutral pion production in pp collisions, in which the spin/isospin channels filter differently the rescattering mechanism. The chiral perturbation theory rescattering amplitude is employed.…
The reaction $NN \to NN \pi$ offers a good testing ground for chiral effective field theory at intermediate energies. It challenges our understanding of the first inelastic channel in nucleon-nucleon scattering and of the charge-symmetry…
Background: At intermediate energies, transfer reactions are suppressed because the momentum-matching condition is difficult to satisfy. In the standard distorted wave Born approximation (DWBA), a high momentum component of the transferred…
Electroproduction of pions on the nucleon near the threshold is analyzed within the framework of baryon chiral perturbation theory. We give a thorough discussion of the low--energy theorems related to charged and neutral…
A status report is given for the current theoretical understanding of pion production close to threshold. In the first part of the talk predictions of a meson exchange model are compared to recent polarized data for the reactions $pp \to…
A model calculation for pion production in nucleon-nucleon collisions is presented. Direct production, pion rescattering and contributions from pair diagrams are taken into account. The amplitudes for the elementary processes are based on…
Within the multiple scattering formulation, the incoherent pion production in neutrino-deuteron reactions at energies near the $\Delta(1232)$ resonance is investigated. The calculations include an impulse term and one-loop contributions…
Large momentum transfer reactions such as pion production represent the frontier of Chiral Perturbation Theory and must be understood before more complex reactions can be considered. Pion production is also interesting in its own right, one…
We report about the recent results for s- and p-wave pion production in NN -> NNpi within effective field theory and discuss how the charge symmetry breaking in pn -> d pi^0 can be used to extract the strong contribution to the…
I study an aspect of chiral perturbation theory (\chi PT) which enables one to ``bridge'' different reactions. That is, an operator fixed in one of the reactions can then be used to predict the other. For this purpose, I calculate the…
The near-threshold n p -> d pi0 cross section is calculated in chiral perturbation theory to next-to-leading order in the expansion parameter sqrt{M m_pi}/Lambda_chi. At this order irreducible pion loops contribute to the relevant…