Dispersion analysis of the strange vector form factors of the nucleon
- European Centre for Theoretical Studies in Nuclear Physics and Related Areas, Villa Tambosi, Strada delle Tabarelle 286, I-38050 Villazzano (Italy)
We analyze the nucleon matrix element of the strange quark vector current in a nucleon-model-independent dispersive approach with input from the current world data set for the isoscalar electromagnetic form factors. The update of Jaffe{close_quote}s minimal three-pole {ital Ansatz} for the spectral functions yields a 40{percent} larger (Sachs) strangeness radius (r{sub s}{sup 2}){sub Sachs}=0.20 fm{sup 2} and a by 20{percent} reduced magnitude of the strangeness magnetic moment {mu}{sub s}={minus}0.26. In the pole approximation these values are shown to be upper bounds. After extending the {ital Ansatz} in order to implement the asymptotic QCD momentum dependence (which the three-pole form factors cannot reproduce), we find the magnitude of the three-pole results reduced by up to a factor of 2.5. The signs of the leading moments originate primarily from the large {phi}-meson couplings and are generic in the pole approximation. {copyright} {ital 1997} {ital The American Physical Society}
- OSTI ID:
- 531934
- Journal Information:
- Physical Review, C, Vol. 56, Issue 1; Other Information: PBD: Jul 1997
- Country of Publication:
- United States
- Language:
- English
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