Nucleon strangeness as a response to a strangeness-sensitive probe in a class of hadron models

Klabučar, Dubravko; Kumerički, Krešimir; Melić, Blaženka; Picek, Ivica (1999) Nucleon strangeness as a response to a strangeness-sensitive probe in a class of hadron models. Fizika B -Zagreb-, 8 (4). pp. 505-534. ISSN 1330-0016

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Abstract

On top of its valence quarks, the full nucleon ground state may contain appreciable admixture of s-\bar{s} pairs already at small momentum transfers. This paper discusses strangeness in the mean-field type of nucleon models, and exemplifies this by explicit calculations in the MIT bag model enriched by the presence of instantons. We calculate the instanton contribution to the strangeness in the MIT bag (on top of the standard contribution to strangeness found in that model). Although we do it in an essentially perturbative way, we present a detailed derivation of the formula expressing nucleon matrix elements of bilinear strange quark operators, in terms of a model valence nucleon state and interactions producing quark-antiquark fluctuations on top of that valence state. We do it in detail to clarify our argument that in the context of the mean-field type of quark models (where a Fock state expansion exists and where the nucleon state can be constructed out of single-quark states), the resulting formula acquires a significance beyond perturbation theory.The derivation combines the usage of the evolution operator containing a strangeness source, and Feynman-Hellmann theorem.

Item Type:	Article
Uncontrolled Keywords:	nucleon strangeness; bag model; instanton model
Subjects:	NATURAL SCIENCES > Physics
Divisions:	Theoretical Physics Division
Projects:	Project title Project leader Project code Project type Teorijska istraživanja osobina fundamentalnih čestica Branko Guberina 00980102 MZOS Struktura elementarnih čestica i kvantna teorija polja Dubravko Tadić 119222 MZOS
Depositing User:	Blaženka Melić
Date Deposited:	09 Feb 2016 13:08
URI:	http://fulir.irb.hr/id/eprint/2459

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