QCD sum-rule study of scalar mesons
In this thesis, QCD Laplace sum-rules for the light quark 'qq ' currents are employed to study the properties of the non-strange ' I' = 0 and 'I' = 1 light quark scalar mesons. This QCD sum-rule analysis allows us to interpret the experimentally observed ' I'...
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ndltd-USASK-oai-usask.ca-etd-10212004-0027512013-01-08T16:32:03Z QCD sum-rule study of scalar mesons Shi, Fang In this thesis, QCD Laplace sum-rules for the light quark 'qq ' currents are employed to study the properties of the non-strange ' I' = 0 and 'I' = 1 light quark scalar mesons. This QCD sum-rule analysis allows us to interpret the experimentally observed ' I' = 0 and 'I' = 1 scalar mesons. The Holder inequality technique is employed to determine the region of validity for the QCD sum-rule, and a stability analysis of the QCD sum-rule prediction is conducted through a Monte-Carlo uncertainty simulation of uncertainties. The field theoretical content of the QCD sum rules incorporates purely-perturbative QCD contributions to two-loop order, leading contributions from QCD-vacuum condensates, and the direct single-instanton contributions in the instanton-liquid QCD vacuum model. Single-instanton contributions are the only components of the QCD field theory that distinguish between isospin states, and therefore they are responsible for breaking the mass degeneracy between the lowest-lying isovector and isoscalarmesons. A novel treatment of instanton effects in QCD continuum contribution is included in this thesis. There is also a need to go beyond the narrow resonance approximation for the scalar channels which are likely to exhibit sensitivity to broad resonance structure. A finite-width effect anticipated from physical resonance widths is incorporated for the hadronic content of the 'I' = 0 and 'I' = 1 QCD sum rules. In the 'I' = 0 channel, our results support interpretation of the 'f'0(980) as the lowest-lying light quark scalar meson, indicating that 'f'0(400 - 1200) is unnaturally decoupled from a light quark non-strange current. In the ' I' = 1 channel, the results identify 'a'0(1450) as the lowest-lying 'qq' resonance, and are indicative of a non-'qq' interpretation for 'a'0(980). Steele, Tom G. University of Saskatchewan 1999-01-01 text application/pdf http://library.usask.ca/theses/available/etd-10212004-002751 http://library.usask.ca/theses/available/etd-10212004-002751 en unrestricted I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University of Saskatchewan or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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In this thesis, QCD Laplace sum-rules for the light quark 'qq ' currents are employed to study the properties of the non-strange ' I' = 0 and 'I' = 1 light quark scalar mesons. This QCD sum-rule analysis allows us to interpret the experimentally observed ' I' = 0 and 'I' = 1 scalar mesons. The Holder inequality technique is employed to determine the region of validity for the QCD sum-rule, and a stability analysis of the QCD sum-rule prediction is conducted through a Monte-Carlo uncertainty simulation of uncertainties. The field theoretical content of the QCD sum rules incorporates purely-perturbative QCD contributions to two-loop order, leading contributions from QCD-vacuum condensates, and the direct single-instanton contributions in the instanton-liquid QCD vacuum model. Single-instanton contributions are the only components of the QCD field theory that distinguish between isospin states, and therefore they are responsible for breaking the mass degeneracy between the lowest-lying isovector and isoscalarmesons. A novel treatment of instanton effects in QCD continuum contribution is included in this thesis. There is also a need to go beyond the narrow resonance approximation for the scalar channels which are likely to exhibit sensitivity to broad resonance structure. A finite-width effect anticipated from physical resonance widths is incorporated for the hadronic content of the 'I' = 0 and 'I' = 1 QCD sum rules. In the 'I' = 0 channel, our results support interpretation of the 'f'0(980) as the lowest-lying light quark scalar meson, indicating that 'f'0(400 - 1200) is unnaturally decoupled from a light quark non-strange current. In the ' I' = 1 channel, the results identify 'a'0(1450) as the lowest-lying 'qq' resonance, and are indicative of a non-'qq' interpretation for 'a'0(980). |
author2 |
Steele, Tom G. |
author_facet |
Steele, Tom G. Shi, Fang |
author |
Shi, Fang |
spellingShingle |
Shi, Fang QCD sum-rule study of scalar mesons |
author_sort |
Shi, Fang |
title |
QCD sum-rule study of scalar mesons |
title_short |
QCD sum-rule study of scalar mesons |
title_full |
QCD sum-rule study of scalar mesons |
title_fullStr |
QCD sum-rule study of scalar mesons |
title_full_unstemmed |
QCD sum-rule study of scalar mesons |
title_sort |
qcd sum-rule study of scalar mesons |
publisher |
University of Saskatchewan |
publishDate |
1999 |
url |
http://library.usask.ca/theses/available/etd-10212004-002751 |
work_keys_str_mv |
AT shifang qcdsumrulestudyofscalarmesons |
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1716531997126426624 |