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Title: Improved description of the πN-scattering phenomenology at low energies in covariant baryon chiral perturbation theory

We present a novel analysis of the πN scattering amplitude in covariant baryon chiral perturbation theory up to O(p{sup 3}) within the extended-on-mass-shell renormalization scheme and including the Δ(1232) explicitly in the δ-counting. We take the hadronic phase shifts provided by partial wave analyses as basic experimental information to fix the low-energy constants. Subsequently, we study in detail the various observables and low-energy theorems related to the πN scattering amplitude. In particular, we discuss the results and chiral expansion of the phase shifts, the threshold coefficients, the Goldberger–Treiman relation, the pion–nucleon sigma term and the extrapolation onto the subthreshold region. The chiral representation of the amplitude in the theory with the Δ presents a good convergence from very low energies in the subthreshold region up to energies above threshold and below the Δ(1232) peak, leading also to a phenomenological description perfectly consistent with the one reported by the respective partial wave analyses and independent determinations. We conclude that a model-independent and systematic framework to analyze πN-scattering observables using directly experimental data shall be possible in covariant baryon chiral perturbation theory. -- Highlights: •The chiral series shows a better convergence than previous analyses. •Improved prediction of the πN scattering phenomenology. •Thismore » analysis connects reliably the subthreshold and physical regions for the first time using ChPT. •Extraction of an accurate value of σ{sub πN} from experimental data. •σ{sub πN} extracted is compatible with related phenomenology.« less
Authors:
 [1] ;  [2] ;  [3]
  1. Institut für Kernphysik, Johannes Gutenberg Universität, Mainz D-55099 (Germany)
  2. Department of Physics and Astronomy, University of Sussex, BN1 9QH, Brighton (United Kingdom)
  3. Departamento de Física, Universidad de Murcia, E-30071, Murcia (Spain)
Publication Date:
OSTI Identifier:
22220786
Resource Type:
Journal Article
Resource Relation:
Journal Name: Annals of Physics (New York); Journal Volume: 336; Other Information: Copyright (c) 2013 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; BARYONS; EXTRAPOLATION; LOW-ENERGY THEOREM; PARTIAL WAVES; PERTURBATION THEORY; PHASE SHIFT; PION-NUCLEON INTERACTIONS; RENORMALIZATION; SCATTERING; SCATTERING AMPLITUDES