Relativistic calculations for incoherent photoproduction of eta mesons

Citation
Ir. Blokland et Hs. Sherif, Relativistic calculations for incoherent photoproduction of eta mesons, NUCL PHYS A, 694(1-2), 2001, pp. 337-350
Citations number
22
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Physics
Journal title
NUCLEAR PHYSICS A
ISSN journal
0375-9474 → ACNP
Volume
694
Issue
1-2
Year of publication
2001
Pages
337 - 350
Database
ISI
SICI code
0375-9474(20011105)694:1-2<337:RCFIPO>2.0.ZU;2-U
Abstract
We develop a relativistic model for incoherent eta -photoproduction on nucl ei. The elementary process is described using an effective Lagrangian conta ining photons, nucleons, the S-11(1535) and D-13(1520) nucleon resonances, and rho, omega and eta mesons. The nucleon and eta wave functions are obtai ned from relativistic wave equations. Final-state interactions of the outgo ing particles are included via optical potentials. The effects of these int eractions are found to be large and lead to reduced cross sections. The inc oherent cross sections for isovector transitions are much larger than those for isoscalar ones. The dominant contributions are those from the S-11 and D-13 resonances. We find important interference effects between the contri butions of these two resonances. We give some detailed calculations for the cross sections for incoherent eta -photoproduction on C-12. We find that t he incoherent cross section for a subset of states in the excitation energy region below 17 MeV are significantly larger than those of the coherent pr ocess. These cross sections may thus be accessible experimentally. (C) 2001 Elsevier Science B.V. All rights reserved.