Loading...
Please wait, while we are loading the content...
Similar Documents
Pion – Nucleon Scattering at Low Energies
| Content Provider | Semantic Scholar |
|---|---|
| Author | Ellis, Paul J. Tang, Honggao |
| Copyright Year | 1996 |
| Abstract | We study pion–nucleon scattering with a chiral lagrangian of pions, nucleons, and ∆-isobars by evaluating the scattering amplitude at tree level to orders Q 2 and Q 3 , where Q is a generic small momentum scale. The O(Q 3) calculation provides a good fit to the experimental phase shifts for pion center-of-mass kinetic energies up to 150 MeV. Our results are independent of the off-shell ∆ parameter. It is important to study pion–nucleon (πN) scattering near threshold, as well as in the resonant region, using modern effective field theories. Several relativistic phenomenological models [1–5] exist which provide reasonably good fits to the experimental πN phase shifts. These models suffer, however, from the uncontrollability of the approximations involved. Although it is generally believed that the ∆ degree of freedom plays an important role in πN scattering, the Z parameter that occurs in the πN∆ vertex has been controversial. A number of papers [1,2,5,6] imply that the Z parameter can be determined to be approximately −0.5 from fits to the πN data. In a recent paper [7] we showed that this Z dependence is absent if the lagrangian is of sufficient generality (see further discussion below). Chiral perturbation theory (ChPT) [8,9] establishes the successful idea of a momentum expansion. We would expect that, provided that the ∆ is retained as an explicit degree of 1 |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://arxiv.org/pdf/hep-ph/9609459v2.pdf |
| Alternate Webpage(s) | http://arxiv.org/pdf/hep-ph/9609459v1.pdf |
| Language | English |
| Access Restriction | Open |
| Subject Keyword | Approximation Chirality (chemistry) Energy, Physics Expect FITS Kinetics Nucleons Paper Perturbation theory Population Parameter Subsurface scattering Vertex biopsychosocial AOD use disorder theory pi-Mesons |
| Content Type | Text |
| Resource Type | Article |
