Nucleon time-like form factors below the NN threshold

Citation
R. Baldini et al., Nucleon time-like form factors below the NN threshold, EUR PHY J C, 11(4), 1999, pp. 709-715
Citations number
74
Categorie Soggetti
Physics
Journal title
EUROPEAN PHYSICAL JOURNAL C
ISSN journal
14346044 → ACNP
Volume
11
Issue
4
Year of publication
1999
Pages
709 - 715
Database
ISI
SICI code
1434-6044(199912)11:4<709:NTFFBT>2.0.ZU;2-A
Abstract
The nucleon magnetic form factors in the unphysical region, i.e., for time- like Q(2) but below the NN threshold, have been obtained by means of disper sion relations in a model-independent way, without any bias towards expecte d resonances. Space-like and time-like data have been employed, along with a regularization unfolding method to solve the integral:equation. Remarkabl y, resonance structures with peaks for the rho(770) and rho'(1600) and a st ructure near the <N(N)over bar> threshold are automatically generated. The obtained rho has a much larger width, whose significance is explored. No ev idence is found for a peak at the Phi mass, in spite of the expectation tha t such a peak exists when there is a sizeable polarized <s(s)over bar> cont ent in the vector current of the nucleon.