Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Dynamics of quarks and leptons: theoretical Studies of Baryons and Neutrinos
KTH, Superseded Departments, Physics.ORCID iD: 0000-0002-3525-8349
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 [en]
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: urn:nbn:se:kth:diva-2991ISBN: 91-7170-537-6 (print)OAI: oai:DiVA.org:kth-2991DiVA: diva2:8735
Public defence
2000-06-09, 00:00
Note
QC 20100616Available from: 2000-06-08 Created: 2000-06-08 Last updated: 2010-06-16Bibliographically approved
List of papers
1. Octet baryon magnetic moments in the chiral quark model with configuration mixing
Open this publication in new window or tab >>Octet baryon magnetic moments in the chiral quark model with configuration mixing
1998 (English)In: Physical Review D. Particles and fields, ISSN 0556-2821, E-ISSN 1089-4918, Vol. 57, no 1, 452-464 p.Article in journal (Refereed) Published
Abstract [en]

The Coleman-Glashow sum-rule for magnetic moments is always fulfilled in the chiral quark model, independently of SU(3) symmetry breaking. This is due to the structure of the wave functions, coming from the non-relativistic quark model. Experimentally, the Coleman-Glashow sum-rule is violated by about ten standard deviations. To overcome this problem, two models of wave functions with configuration mixing are studied. One of these models violates the Coleman-Glashow sum-rule to the right degree and also reproduces the octet baryon magnetic moments rather accurately.

Place, publisher, year, edition, pages
The American Physical Society, 1998
National Category
Subatomic Physics
Identifiers
urn:nbn:se:kth:diva-13372 (URN)10.1103/PhysRevD.57.452 (DOI)000071320700049 ()
Funder
Swedish Research Council, F-AA/FU03281-310
Note
QC 20100616Available from: 2011-06-21 Created: 2010-06-16 Last updated: 2017-12-12Bibliographically approved
2. Decuplet baryon magnetic moments in the chiral quark model
Open this publication in new window or tab >>Decuplet baryon magnetic moments in the chiral quark model
1998 (English)In: Physical Review D. Particles and fields, ISSN 0556-2821, E-ISSN 1089-4918, Vol. 57, no 9, 5916-5919 p.Article in journal (Refereed) Published
Abstract [en]

We present calculations of the decuplet baryon magnetic moments in the chiral quark model. As input we use parameters obtained in qualitatively accurate fits to the octet baryon magnetic moments studied previously. The values found for the magnetic moments of Delta(++) and Omega(-) are in good agreement with experiments. We finally calculate the total quark spin polarizations of the decuplet baryons and find that they are considerably smaller than what is expected from the non-relativistic quark model.

Place, publisher, year, edition, pages
The American Physical Society, 1998
National Category
Subatomic Physics
Identifiers
urn:nbn:se:kth:diva-13377 (URN)10.1103/PhysRevD.57.5916 (DOI)000073464200066 ()
Funder
Swedish Research Council, F-AA/FU03281-310
Note
QC 20100616Available from: 2011-06-21 Created: 2010-06-16 Last updated: 2017-12-12Bibliographically approved
3. Weak form factors for semileptonic octet baryon decays in the chiral quark model
Open this publication in new window or tab >>Weak form factors for semileptonic octet baryon decays in the chiral quark model
1999 (English)In: European Physical Journal C, ISSN 1434-6044, E-ISSN 1434-6052, Vol. 6, no 2, 285-296 p.Article in journal (Refereed) Published
Abstract [en]

We study the weak vector and axial-vector form factors of first- and second-class currents for the semileptonic octet baryon decays in the spirit of the chiral quark model. Our results for the weak magnetism form factors are consistent with the conserved vector current (CVC) results. The induced pseudotensor form factors, which are highly model dependent. are small. The overall performance of the chiral quark model is quite good and in general agreement with existing experimental data.

Place, publisher, year, edition, pages
Springer-Verlag, 1999
National Category
Subatomic Physics
Identifiers
urn:nbn:se:kth:diva-13374 (URN)10.1007/s100529800908 (DOI)000077853000007 ()
Funder
Swedish Research Council, F-AA/FU03281-310
Note
QC 20100616Available from: 2011-06-21 Created: 2010-06-16 Last updated: 2017-12-12Bibliographically approved
4. Weak magnetism in chiral quark models
Open this publication in new window or tab >>Weak magnetism in chiral quark models
2000 (English)In: European Physical Journal C, ISSN 1434-6044, E-ISSN 1434-6052, Vol. 12, no 2, 271-276 p.Article in journal (Refereed) Published
Abstract [en]

We discuss symmetry breaking in the weak magnetism form factors for the semileptonic octet baryon decays. In the chiral quark model, the symmetry breaking can be accounted for in the masses and the quark spin polarizations can take on more general values due to Goldstone boson depolarization. Here we clarify some features of the chiral quark model prediction for the weak magnetism and compare to the corresponding result of the chiral quark soliton model.

Place, publisher, year, edition, pages
Springer-Verlag, 2000
National Category
Subatomic Physics
Identifiers
urn:nbn:se:kth:diva-13373 (URN)10.1007/s100529900264 (DOI)000085316300006 ()
Funder
Swedish Research Council, F-AA/FU03281-312
Note
QC 20100616Available from: 2011-06-21 Created: 2010-06-16 Last updated: 2017-12-12Bibliographically approved
5. Chiral quark model analysis of nucleon quark sea isospin asymmetry and spin polarization
Open this publication in new window or tab >>Chiral quark model analysis of nucleon quark sea isospin asymmetry and spin polarization
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
National Category
Subatomic Physics
Identifiers
urn:nbn:se:kth:diva-13375 (URN)10.1007/s100529801048 (DOI)000079148500009 ()
Funder
Swedish Research Council, F-AA/FU03281-311
Note
QC 20110622Available from: 2011-06-22 Created: 2010-06-16 Last updated: 2017-12-12Bibliographically approved
6. Neutrino oscillations and mixings with three flavors
Open this publication in new window or tab >>Neutrino oscillations and mixings with three flavors
1999 (English)In: Physical Review D. Particles and fields, ISSN 0556-2821, E-ISSN 1089-4918, Vol. 60, no 9, 093007-1-093007-8 p.Article in journal (Refereed) Published
Abstract [en]

Global fits to all data of candidates for neutrino oscillations are presented in the framework of a three-flavor model. The analysis excludes mass regions where the MSW effect is important for the solar neutrino problem. The best fit gives theta(1) approximate to 28.9 degrees, theta(2) approximate to 4.2 degrees, theta(3) approximate to 45.0 degrees, m(2)(2) - m(1)(2) approximate to 2.87 X 10(-4) eV(2), and m(3)(2) - m(2)(2) approximate to 1.11 eV(2) indicating essentially maximal mixing between the two lightest neutrino mass eigenstates.

Place, publisher, year, edition, pages
The American Physical Society, 1999
National Category
Subatomic Physics
Identifiers
urn:nbn:se:kth:diva-13376 (URN)10.1103/PhysRevD.60.093007 (DOI)000083430800015 ()
Funder
Swedish Research Council, F-AA/FU03281-312
Note
QC 20100616Available from: 2011-06-22 Created: 2010-06-16 Last updated: 2017-12-12Bibliographically approved
7. Matter enhanced neutrino oscillations with a realistic earth density profile
Open this publication in new window or tab >>Matter enhanced neutrino oscillations with a realistic earth density profile
2000 (English)In: Modern Physics Letters A, ISSN 0217-7323, E-ISSN 1793-6632, Vol. 15, no 13, 867-874 p.Article in journal (Refereed) Published
Abstract [en]

We have investigated matter enhanced neutrino oscillations with a mantle-core-mantle step function and a realistic Earth matter density profile in both a two- and a three-neutrino scenario. We found that the realistic Earth matter density profile can be well approximated with the mantle-core-mantle step function and that there could be an influence on the oscillation channel nu(mu) --> nu(tau) due to resonant enhancement of one of the mixing angles.

Place, publisher, year, edition, pages
World Scientific Publishing, 2000
Keyword
Atmospheric neutrinos, parametric-resonance, solar, spectroscopy
National Category
Subatomic Physics
Identifiers
urn:nbn:se:kth:diva-13380 (URN)10.1142/S0217732300000864 (DOI)000087853200006 ()
Note
QC 20100616Available from: 2011-06-22 Created: 2010-06-16 Last updated: 2017-12-12Bibliographically approved
8. Three flavor neutrino oscillations in matter
Open this publication in new window or tab >>Three flavor neutrino oscillations in matter
2000 (English)In: Journal of Mathematical Physics, ISSN 0022-2488, E-ISSN 1089-7658, Vol. 41, no 5, 2768-2788 p.Article in journal (Refereed) Published
Abstract [en]

We derive analytic expressions for three flavor neutrino oscillations in the presence of matter in the plane wave approximation using the Cayley-Hamilton formalism. Especially, we calculate the time evolution operator in both flavor and mass bases. Furthermore, we find the transition probabilities, matter mass squared differences, and matter mixing angles all expressed in terms of the vacuum mass squared differences, the vacuum mixing angles, and the matter density. The conditions for resonance in the presence of matter are also studied in some examples.

Place, publisher, year, edition, pages
American Institute of Physics, 2000
Keyword
neutrino oscillations, neutrino mass, mass differences, probability
National Category
Subatomic Physics
Identifiers
urn:nbn:se:kth:diva-13379 (URN)10.1063/1.533270 (DOI)000086568600018 ()
Funder
Swedish Research Council, F-AA/FU03281-312
Note
QC 20100616Available from: 2011-06-21 Created: 2010-06-16 Last updated: 2017-12-12Bibliographically approved
9. Neutrino oscillations with three flavors in matter: Applications to neutrinos traversing the earth
Open this publication in new window or tab >>Neutrino oscillations with three flavors in matter: Applications to neutrinos traversing the earth
2000 (English)In: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 474, no 1-2, 153-162 p.Article in journal (Refereed) Published
Abstract [en]

Analytic formulas are presented for three flavor neutrino oscillations in matter in the plane wave approximation. We calculate in particular the time evolution operator in both mass and flavor bases. We also find the transition probabilities expressed as functions of the vacuum mass squared differences, the vacuum mixing angles, and the matter density parameter. The application of this to neutrino oscillations for both atmospheric and long baseline neutrinos in a mantle-core-mantle step function model of the Earth's matter density profile is discussed.

Place, publisher, year, edition, pages
Elsevier Science B.V., 2000
Keyword
3-neutrino oscillations, atmospheric neutrinos, parametric-resonance, solar neutrinos
National Category
Subatomic Physics
Identifiers
urn:nbn:se:kth:diva-13378 (URN)10.1016/S0370-2693(00)00008-3 (DOI)000087121300024 ()
Funder
Swedish Research Council, F-AA/FU03281-312
Note
QC 20100616Available from: 2011-06-21 Created: 2010-06-16 Last updated: 2017-12-12Bibliographically approved

Open Access in DiVA

fulltext(1308 kB)852 downloads
File information
File name FULLTEXT01.pdfFile size 1308 kBChecksum MD5
1b10dd8805e38929754837b034422353afe1b90ba91929efd028141d55aaa727c6ecfeb0
Type fulltextMimetype application/pdf

Authority records BETA

Ohlsson, Tommy

Search in DiVA

By author/editor
Ohlsson, Tommy
By organisation
Physics
Other Physics Topics

Search outside of DiVA

GoogleGoogle Scholar
Total: 852 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

isbn
urn-nbn

Altmetric score

isbn
urn-nbn
Total: 316 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf