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Chiral quark model analysis of nucleon quark sea isospin asymmetry and spin polarization
KTH, Superseded Departments, Physics.ORCID iD: 0000-0002-3525-8349
KTH, Superseded Departments, Physics.
1999 (English)In: European Physical Journal C, ISSN 1434-6044, E-ISSN 1434-6052, Vol. 7, no 3, 501-506 p.Article in journal (Refereed) Published
Abstract [en]

We analyze recent measurements of the nucleon quark sea isospin asymmetry in terms of the chiral quark model. The new measurements indicate that the SU(3) model with modest symmetry breaking and no eta' Goldstone boson gives a satisfactory description of data. We also discuss the matching parameter for the axial-vector current. Finally, we analyze the nucleon quark spin polarization measurements directly in the chiral quark model without using any SU(3) symmetry assumption on the hyperon axial-vector form factors. The new data indicate that the chiral quark model gives a remarkably good and consistent description of all low energy baryon measurements.

Place, publisher, year, edition, pages
Springer-Verlag , 1999. Vol. 7, no 3, 501-506 p.
National Category
Subatomic Physics
Identifiers
URN: urn:nbn:se:kth:diva-13375DOI: 10.1007/s100529801048ISI: 000079148500009OAI: oai:DiVA.org:kth-13375DiVA: diva2:324765
Funder
Swedish Research Council, F-AA/FU03281-311
Note
QC 20110622Available from: 2011-06-22 Created: 2010-06-16 Last updated: 2011-06-22Bibliographically approved
In thesis
1. Dynamics of quarks and leptons: theoretical Studies of Baryons and Neutrinos
Open this publication in new window or tab >>Dynamics of quarks and leptons: theoretical Studies of Baryons and Neutrinos
2000 (English)Doctoral thesis, comprehensive summary (Other scientific)
Abstract [en]

The Standard Model of Elementary Particle Physics (SM) is the present theoryfor the elementary particles and their interactions and is a well-established theorywithin the physics community. The SM is a combination of Quantum Chromodynamics(QCD) and the Glashow{Weinberg{Salam (GWS) electroweak model. QCDis a theory for the strong force, whereas the GWS electroweak model is a theoryfor the weak and electromagnetic forces. This means that the SM describes allfundamental forces in Nature, except for the gravitational force. However, the SMis not a nal theory and some of its problems will be discussed in this thesis.In the rst part of this thesis, several properties of baryons are studied suchas spin structure, spin polarizations, magnetic moments, weak form factors, andnucleon quark sea isospin asymmetries, using the chiral quark model (QM). TheQM is an eective chiral eld theory developed to describe low energy phenomena of baryons, since perturbative QCD is not applicable at low energies. The resultsof the QM are in good agreement with experimental data.The second part of the thesis is devoted to the concept of quantum mechanicalneutrino oscillations. Neutrino oscillations can, however, not occur within the GWSelectroweak model. Thus, this model has to be extended in some way. All studiesincluding neutrino oscillation are done within three avor neutrino oscillationmodels. Both vacuum and matter neutrino oscillations are considered. Especially,global ts to all data of candidates for neutrino oscillations are presented and alsoan analytical formalism for matter enhanced three avor neutrino oscillations usingtime evolution operators is derived. Furthermore, investigations of matter eectswhen neutrinos traverse the Earth are included.The thesis begins with an introductory review of the QM and neutrino oscillationsand ends with the research results, which are given in the nine accompanyingscientic articles.

Place, publisher, year, edition, pages
Stockholm: KTH, 2000. xiv, 152 p.
Series
Trita-FYS, ISSN 0280-316X ; 8045
Keyword
Chiral quark model, baryons, conguration mixing, magnetic moments, Coleman{Glashow sum-rule, spin structure, spin polarizations, weak form factors, semileptonic decays, nucleon quark sea isospin asymmetry; neutrinos, neutrino oscillations, neutrino avors, mixing angles, mass squared dierences, MSW eect; numerical calculations, interpretation of experiments
National Category
Other Physics Topics
Identifiers
urn:nbn:se:kth:diva-2991 (URN)91-7170-537-6 (ISBN)
Public defence
2000-06-09, 00:00
Note
QC 20100616Available from: 2000-06-08 Created: 2000-06-08 Last updated: 2010-06-16Bibliographically approved

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Publisher's full textEuropean Physical Journal Chttp://arxiv.org/abs/hep-ph/9805309

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