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Titolo:
Low energy analysis of pi N -> pi N
Autore:
Becher, T; Leutwyler, H;
Indirizzi:
Cornell Univ, Newman Lab Nucl Studies, Ithaca, NY 14853 USA Cornell Univ Ithaca NY USA 14853 n Lab Nucl Studies, Ithaca, NY 14853 USA Univ Bern, Inst Theoret Phys, CH-3012 Bern, Switzerland Univ Bern Bern Switzerland CH-3012 eoret Phys, CH-3012 Bern, Switzerland
Titolo Testata:
JOURNAL OF HIGH ENERGY PHYSICS
fascicolo: 6, volume: 2001, anno: 2001,
pagine: NIL_404 - NIL_489
SICI:
1029-8479(200106)2001:6<NIL_404:LEAOPN>2.0.ZU;2-3
Fonte:
ISI
Lingua:
ENG
Soggetto:
CHIRAL PERTURBATION-THEORY; NUCLEON SIGMA-TERM; SCATTERING LENGTHS; PARTIAL-WAVES; FORM-FACTOR; ANALYTICITY; EXPANSION; DYNAMICS; LOOPS; MESON;
Keywords:
QCD; chiral lagrangians;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
78
Recensione:
Indirizzi per estratti:
Indirizzo: Becher, T Cornell Univ, Newman Lab Nucl Studies, Ithaca, NY 14853 USA Cornell Univ Ithaca NY USA 14853 Studies, Ithaca, NY 14853 USA
Citazione:
T. Becher e H. Leutwyler, "Low energy analysis of pi N -> pi N", J HIGH EN P, 2001(6), 2001, pp. NIL_404-NIL_489

Abstract

We derive a representation for the pion nucleon scattering amplitude that is valid to the fourth order of the chiral expansion. To obtain the correctanalytic structure of the singularities in the low energy region, we have performed the calculation in a relativistic framework (infrared regularization). The result can be written in terms of functions of a single variable. We study the corresponding dispersion relations and discuss the problems encountered in the straightforward nonrelativistic expansion of the infraredsingularities. As an application, we evaluate the corrections to the Goldberger-Treiman relation and to the low energy theorem that relates the valueof the amplitude at the Cheng-Dashen point to the sigma -term. While chiral symmetry does govern the behaviour of the amplitude in the vicinity of this point, the representation for the scattering amplitude is not accurate enough to use it for an extrapolation of the experimental data to the subthreshold region. We propose to perform this extrapolation on the basis of a set of integral equations that interrelate the lowest partial waves and are analogous to the Roy equations for pi pi scattering.

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Documento generato il 02/04/20 alle ore 07:17:02