Summary
The former modified six-resonance VMD model with the correct analytic properties of nucleon electromagnetic form factors and the asymptotic behaviour predicted by the quark model for baryons is improved, first by an addition of the \gr\s`(2150) meson contribution, then taking masses and widths of all considered resonances to be fixed at the world-averaged values and finally, differing also the effective inelastic threshold of the isoscalar (isovector) Dirac nucleon form factor from the effective inelastic threshold of the isoscalar (isovector) Pauli nucleon form factor. By means of the resultant model the analysis of all existing spacelike region nucleon form factor data is repeated. In the timelike region just the attainable data on\(e^ + e^ - \to p\overline p \) cross-section are employed and the assumption currently used by experimentalists about the equality of electric and magnetic proton form factors close above the proton-antiproton threshold is tested in this manner. The prediction of the\(e^ + e^ - \to n\overline n \) cross-section to be remarkably larger than the\(e^ + e^ - \to p\overline p \) one is established again.
Similar content being viewed by others
References
S. Dubniĉka:Nuovo Cimento A,100, 1 (1988).
M. Gourdin:Phys. Rep. C,11, 29 (1974).
R. Eden, P. Landshoff, D. Olive andJ. Polkinghorn:The analytic S-matrix (Cambridge University Press, Cambridge, 1966).
S. Dubniĉka andO. Dumbrajs:Phys. Rep. C,19, 140 (1975).
Review of Particle Properties:Phys. Lett. B,204, 1 (1988).
N. Cabibbo andR. Gatto:Phys. Rev.,124, 1577 (1961).
J. G. Körner andM. Kuroda:Phys. Rev. D,16, 2165 (1977).
P. Cesselini, M. Nigro andC. Voci: inProceedings of a Workshop on Physics at LEAR with Low-Energy Cooled Antiprotons, Erice, 1982, p. 365.
R. Baldini-Ferroli, S. Dubniĉka, E. Etim andP. Kolář: in preparation.
A. B. Clegg andA. Donnachie: preprint M/C-TH 89/27 (Manchester, 1989).
A. Donnachie andH. Mirzaie:Z. Phys. C,33, 407 (1987).
S. Dubniĉka, I. Furdik andV. A. Meshcheryakov: preprint JINR, E2-88-521 (Dubna, 1988).
S. Dubniĉka: preprint JINR, E2-88-840 (Dubna, 1988).
Author information
Authors and Affiliations
Additional information
The author of this paper has agreed to not receive the proofs for correction.
An erratum to this article is available at http://dx.doi.org/10.1007/BF02813362.
Rights and permissions
About this article
Cite this article
Dubniĉka, S. Comment on the prediction of the\(e^ + e^ - \to n\overline n \) cross-section to be remarkably larger than the\(e^ + e^ - \to p\overline p \) . Nuov Cim A 103, 1417–1426 (1990). https://doi.org/10.1007/BF02820570
Received:
Published:
Issue Date:
DOI: https://doi.org/10.1007/BF02820570