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FIZIKA B 16 (2007) 2, 89 - 98
 
UNEXPECTEDLY SMALL EMPIRICAL VECTOR STRANGENESS OF NUCLEONS PREDICTED IN A BARION MODEL
D. HORVATIĆ a, D. KLABUČARa,b, and D. MEKTEROVIĆ c
aDepartment of Physics, Faculty of Science, University of Zagreb, Bijenička 32, Zagreb, Croatia
bInternational Centre for Theoretical Physics, Trieste, Italy
cRuđer Bošković Institute, P. O. Box 180, HR-10002 Zagreb, CroatiaReceived 14 March 2007; Revised manuscript received 16 June 2007
Accepted 20 June 2007 Online 12 July 2007
Most of model considerations of the hidden nucleon strangeness, as well as some
preliminary experimental evidence, led to the expectations of relatively
sizeable strange vector form factors of the proton. For example, it seemed that
the contribution of the fluctuating strange quark-antiquark pairs accounts for
as much as one tenth of the proton's magnetic moment. By the same token, baryon
models which failed to produce the "vector strangeness" of the nucleon seemed
disfavoured. Recently, however, more accurate measurements and more
sophisticated data analysis, as well as lattice simulations, revealed that the
form factors associated with the vector strangeness of the nucleon are much
smaller than thought previously; in fact, due to the experimental uncertainties,
the measured strange vector-current proton form factors may be consistent with
zero. In the light of that, we re-asses the merit of the baryon models leading
to little or no vector strangeness of the nucleon. It is done on the concrete
example of the baryon model which essentially amounts to the MIT bag enriched by
the diluted instanton liquid.
PACS numbers: 14.20.Dh, 13.40.Em, 12.39.Ba,
UDC 539.125
Keywords: proton, magnetic moment, strange vector form factor, strange quark-antiquark
pairs, MIT bag enriched by the diluted instanton liquid
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