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Texas A&M University
1.
Bencomo, Miguel.
Superallowed β-Decay Branching Ratio Measurement of 26Si.
Degree: PhD, Physics, 2018, Texas A&M University
URL: http://hdl.handle.net/1969.1/174335 
► As part of the continued effort to test the unitarity of the Cabbibo-Kobayashi-Maskawa matrix, the branching ratio for the Tvz = -1 superallowed 0+ →…
(more)
▼ As part of the continued effort to test the unitarity of the Cabbibo-Kobayashi-Maskawa
matrix, the branching ratio for the Tvz = -1
superallowed 0
+ → 0
+ positron-emitter
26Si was
measured precisely for the first time. Since the QvEC value, 4840.86(10) keV, and half-life,
2245.3(7) ms, are known precisely, the branching ratio is all that is required to obtain a
precise ft value. This completes the second pair of mirror
superallowed transitions,
26Si →
26mAl and 26mAl →
26Mg. A previous measurement of the mirror transitions,
38Ca →
38mK
and
38mK →
38Ar, showed that the ratio of mirror ft-values is very sensitive to the model
used to calculate the small isospin symmetry-breaking corrections required to extract Vvud. In
calculating this correction, both Woods-Saxon and Hartree-Fock radial wave functions have
been used, with the experimental results from the first pair favoring Woods-Saxon. The
result for the A = 26 mirror pair demonstrates that this conclusion can be generalized.
Advisors/Committee Members: Hardy, John C (advisor), Melconian, Dan (committee member), Yennello, Sherry (committee member), Ko, Che-Ming (committee member).
Subjects/Keywords: Superallowed; beta decay; branching ratio
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APA (6th Edition):
Bencomo, M. (2018). Superallowed β-Decay Branching Ratio Measurement of 26Si. (Doctoral Dissertation). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/174335
Chicago Manual of Style (16th Edition):
Bencomo, Miguel. “Superallowed β-Decay Branching Ratio Measurement of 26Si.” 2018. Doctoral Dissertation, Texas A&M University. Accessed April 15, 2021.
http://hdl.handle.net/1969.1/174335.
MLA Handbook (7th Edition):
Bencomo, Miguel. “Superallowed β-Decay Branching Ratio Measurement of 26Si.” 2018. Web. 15 Apr 2021.
Vancouver:
Bencomo M. Superallowed β-Decay Branching Ratio Measurement of 26Si. [Internet] [Doctoral dissertation]. Texas A&M University; 2018. [cited 2021 Apr 15].
Available from: http://hdl.handle.net/1969.1/174335.
Council of Science Editors:
Bencomo M. Superallowed β-Decay Branching Ratio Measurement of 26Si. [Doctoral Dissertation]. Texas A&M University; 2018. Available from: http://hdl.handle.net/1969.1/174335
University of Guelph
2.
Dunlop, Michelle.
High-Precision Half-Life Measurements for the Superallowed Beta+ Emitters 10C and 22Mg.
Degree: PhD, Department of Physics, 2018, University of Guelph
URL: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/14154
► High precision measurements of the ft values for superallowed Fermi β transitions be- tween Jπ = 0+, T = 1 isobaric analogue states allow for…
(more)
▼ High precision measurements of the ft values for
superallowed Fermi β transitions be- tween Jπ = 0+, T = 1 isobaric analogue states allow for stringent tests of the electroweak interaction described by the Standard Model. These transitions provide an experimental probe of the Conserved-Vector-Current hypothesis, the most precise determination of Vud, the up- down element of the Cabibbo-Kobayashi-Maskawa quark-mixing matrix, and set stringent limits on the existence of scalar currents in the weak interaction.
This thesis focuses on high-precision half-life measurements of two
superallowed Fermi β+ emitters, 10C and 22Mg. These half-life measurements were performed at TRIUMF’s Isotope Separator and Accelerator facility. For both cases, measurements of their half-lives were motivated by the discrepancies between previous measurements found in literature that resulted in inflations in the uncertainties to account for the inconsistent measurements.
Two independent measurements of the 10C half-life were performed. The first measurement was performed via γ-ray photopeak counting using the 8π γ-ray spectrometer, an array of 20 Compton-suppressed high-purity germanium detectors, by measuring the time profile of the characteristic 718-keV γ-ray. This analysis yielded T1/2 = 19.2969 ± 0.0072 s. A second measurement was performed via direct β counting, using a 4π continuous-flow gas proportional β counter. The results from this analysis yields T1/2 = 19.3009 ± 0.0017 s, and is the most precise
superallowed half-life measurement reported to date and the first to ever achieve a relative precision below 10−4.
A half-life measurement of the
superallowed β+ emitter 22Mg was performed via direct β counting using the 4π continuous-flow gas proportional counter. This analysis yielded a half-life of T1/2 = 3.87400 ± 0.0079 s. This measurement resolved a discrepancy between the previous world-average dataset, which was composed of only two measurements. These two half-life measurements showed a disagreement characterized by a χ2/ν = 4.0, however, upon the inclusion of the new measurement presented in this thesis, now has a χ2/ν = 1.1.
The high-precision half-life measurements reported in this thesis, once included with the other high-precision
superallowed data, can be used to test fundamental properties of the Standard Model. In particular, the improved uncertainty of the 10C half-life can be used to provide a more stringent limit on the contribution of scalar currents in the Standard Model. The improvement in the uncertainty of the 22Mg half-life provides further tests of the isospin symmetry breaking corrections in
superallowed Fermi β decays.
Advisors/Committee Members: Svensson, Carl (advisor).
Subjects/Keywords: Nuclear Physics; Superallowed Beta Decay; Half-Life; Beta Decay
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APA (6th Edition):
Dunlop, M. (2018). High-Precision Half-Life Measurements for the Superallowed Beta+ Emitters 10C and 22Mg. (Doctoral Dissertation). University of Guelph. Retrieved from https://atrium.lib.uoguelph.ca/xmlui/handle/10214/14154
Chicago Manual of Style (16th Edition):
Dunlop, Michelle. “High-Precision Half-Life Measurements for the Superallowed Beta+ Emitters 10C and 22Mg.” 2018. Doctoral Dissertation, University of Guelph. Accessed April 15, 2021.
https://atrium.lib.uoguelph.ca/xmlui/handle/10214/14154.
MLA Handbook (7th Edition):
Dunlop, Michelle. “High-Precision Half-Life Measurements for the Superallowed Beta+ Emitters 10C and 22Mg.” 2018. Web. 15 Apr 2021.
Vancouver:
Dunlop M. High-Precision Half-Life Measurements for the Superallowed Beta+ Emitters 10C and 22Mg. [Internet] [Doctoral dissertation]. University of Guelph; 2018. [cited 2021 Apr 15].
Available from: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/14154.
Council of Science Editors:
Dunlop M. High-Precision Half-Life Measurements for the Superallowed Beta+ Emitters 10C and 22Mg. [Doctoral Dissertation]. University of Guelph; 2018. Available from: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/14154
University of Guelph
3.
Dunlop, Ryan.
High-Precision Branching Ratio Measurement for the Superallowed β+ Emitter 74Rb.
Degree: MS, Department of Physics, 2012, University of Guelph
URL: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/3514
► Precision measurements of superallowed Fermi β-decay allow for stringent tests of the magnitude of isospin-symmetry-breaking effects in nuclei, the validity of the conserved vector current…
(more)
▼ Precision measurements of
superallowed Fermi β-
decay allow for stringent tests of the magnitude of isospin-symmetry-breaking effects in nuclei, the validity of the conserved vector current hypothesis, and the unitarity of the Cabibbo-Kobayashi-Maskawa (CKM) quark-mixing matrix. A high-precision measurement of the branching ratio for the
superallowed β+
decay of 74Rb has been performed at the Isotope Separator and ACcelerator (ISAC) facility at TRIUMF. The 8π spectrometer, an array of 20 HPGe detectors, was used to detect γ-rays emitted following the Gamow-Teller and non-analogue Fermi β-decays of 74Rb. PACES, an array of 5 Si(Li) detectors, was used to detect emitted conversion electrons, while half of SCEPTAR, a close-packed array of 10 plastic scintillators, was used to detect emitted β particles. In this experiment, 23 excited states were identified in 74Kr which were populated following the β-
decay of 74Rb. A total of 58 γ-rays were identified following the 8.241(4)x108 detected β-particles. An observed non-
superallowed branching ratio of 0.396(7)% was determined from the intensity of the identified γ-rays, while the unobserved non-
superallowed intensity was calculated to be 0.05(5)%, leading to a
superallowed branching ratio of 99.55(5)%. The
superallowed branching ratio is now the most precise experimental quantity in the determination of the
superallowed ft-value of 74Rb. Combining the half-life and Q-value with the
superallowed branching ratio measured in this work leads to a
superallowed ft-value of 3082.6(66) s. Finally, comparisons between the
superallowed ft-value, the world average Ft-value, and the non-analogue Fermi branching ratio are made to provide future guidance in the refinement of the theoretical models required to describe the crucial isospin-symmetry-breaking term in
superallowed β-
decay.
Advisors/Committee Members: Svensson, Carl (advisor).
Subjects/Keywords: Superallowed; beta decay; isospin-symmetry-breaking; Cabibbo-Kobayashi-Maskawa; CKM; conserved-vector-current; CVC; Standard Model; gamma-ray spectroscopy; TRIUMF
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APA (6th Edition):
Dunlop, R. (2012). High-Precision Branching Ratio Measurement for the Superallowed β+ Emitter 74Rb. (Masters Thesis). University of Guelph. Retrieved from https://atrium.lib.uoguelph.ca/xmlui/handle/10214/3514
Chicago Manual of Style (16th Edition):
Dunlop, Ryan. “High-Precision Branching Ratio Measurement for the Superallowed β+ Emitter 74Rb.” 2012. Masters Thesis, University of Guelph. Accessed April 15, 2021.
https://atrium.lib.uoguelph.ca/xmlui/handle/10214/3514.
MLA Handbook (7th Edition):
Dunlop, Ryan. “High-Precision Branching Ratio Measurement for the Superallowed β+ Emitter 74Rb.” 2012. Web. 15 Apr 2021.
Vancouver:
Dunlop R. High-Precision Branching Ratio Measurement for the Superallowed β+ Emitter 74Rb. [Internet] [Masters thesis]. University of Guelph; 2012. [cited 2021 Apr 15].
Available from: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/3514.
Council of Science Editors:
Dunlop R. High-Precision Branching Ratio Measurement for the Superallowed β+ Emitter 74Rb. [Masters Thesis]. University of Guelph; 2012. Available from: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/3514
4.
Magron, Cécile.
Mesures précises des demi-vies et rapports d’embranchement pour la décroissance β des noyaux miroir 23Mg et 27Si : Precise measurement of half-lives and branching ratios for the mirror β decay of 23Mg and 27Si.
Degree: Docteur es, Astrophysique, plasmas, nucléaire, 2016, Bordeaux
URL: http://www.theses.fr/2016BORD0180
► L’étude de la décroissance β est un outil fantastique pour approfondir notreconnaissance de l’interaction faible décrite par le Modèle Standard. Ce modèle et laphysique au-delà…
(more)
▼ L’étude de la décroissance β est un outil fantastique pour approfondir notreconnaissance de l’interaction faible décrite par le Modèle Standard. Ce modèle et laphysique au-delà peuvent être testés par des mesures précises de paramètres caractérisantces décroissances. Parmi ces tests, la vérification de l’hypothèse de la conservation ducourant vectoriel (CVC) et de l’unitarité de la matrice de mélange des quarks de Cabibbo-Kobayashi-Maskawa (CKM) sont d’un grand intérêt. Pour cela, les paramètres caractérisantles transitions β doivent être déterminés très précisément. Les meilleures précisions ont étéobtenues pour les transitions super-permises de Fermi de type 0+ → 0+. Cependant, il existed’autres types de décroissances pour réaliser ces tests, par exemple, les décroissances βmiroir. À ce jour, elles ne permettent pas d’atteindre les précisions obtenues avec lestransitions de type 0+ → 0+. Pour améliorer cela, de nouvelles mesures très précises desparamètres expérimentaux caractérisant ces transitions, comme la demi-vie et le rapportd’embranchement, sont nécessaires. C’est pourquoi une expérience a été réalisée àl’université de Jyväskylä en Finlande, afin d’étudier la décroissance β des noyaux miroir 23Mget 27Si et de mesurer ces paramètres. Les valeurs des demi-vies obtenues pour ces deuxnoyaux sont respectivement dix fois et sept fois plus précises que les moyennes de lalittérature. La valeur obtenue pour le rapport d’embranchement de 23Mg est trois fois plusprécise que la moyenne de la littérature, celui de 27Si étant déjà connu avec une très grandeprécision (0,02%), n’a pas été déterminé avec une meilleure précision.
Beta decays are a fantastic tool to study the weak interaction described by theStandard Model. This model and the physics beyond can be tested by precisemeasurements of nuclear β decays. Among these tests, the conserved vector current (CVC)hypothesis and the unitarity of the Cabibbo-Kobayashi-Maskawa (CKM) quark-mixing matrixare of great interest. For these, the parameters of β transitions must be precisely determined.The highest precisions have been obtained with superallowed 0+ → 0+ Fermi β decays.However, there are other possibilities to make these tests, for example mirror β decays. Fornow, they do not allow to achieve the precision of the 0+ → 0+ transitions. To improve this,new accurate measurements of experimental parameters characterizing these transitions,such as the half-life and the branching ratio, are needed. For this purpose, an experimenthas been carried out at the University of Jyväskylä to study the mirror β decays of 23Mg and27Si and to measure these parameters. The half-life values obtained for these two nuclei are,respectively, ten times and seven times more precise than the literature averages. The valueof the branching ratio obtained for 23Mg is three times more precise than the literatureaverage; the one of 27Si has not been improved as it is already precisely known (0.02%).
Advisors/Committee Members: Blank, Bertram (thesis director).
Subjects/Keywords: Décroissance β miroir; Transitions super-permises de Fermi 0+ → 0+; Modèle Standard; Hypothèse CVC; Matrice de mélange des quarks CKM; 23Mg et 27Si; Demi-vies; Rapports d’embranchement; Correction de la brisure de la symétrie d’isospin; Mirror β decay; Superallowed 0+ → 0+ Fermi transitions; Standard Model; CVC hypothesis; CKM quark mixing matrix; 23Mg and 27Si; Half-lives; Branching ratios; Isospin symmetry breaking correction
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APA ·
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APA (6th Edition):
Magron, C. (2016). Mesures précises des demi-vies et rapports d’embranchement pour la décroissance β des noyaux miroir 23Mg et 27Si : Precise measurement of half-lives and branching ratios for the mirror β decay of 23Mg and 27Si. (Doctoral Dissertation). Bordeaux. Retrieved from http://www.theses.fr/2016BORD0180
Chicago Manual of Style (16th Edition):
Magron, Cécile. “Mesures précises des demi-vies et rapports d’embranchement pour la décroissance β des noyaux miroir 23Mg et 27Si : Precise measurement of half-lives and branching ratios for the mirror β decay of 23Mg and 27Si.” 2016. Doctoral Dissertation, Bordeaux. Accessed April 15, 2021.
http://www.theses.fr/2016BORD0180.
MLA Handbook (7th Edition):
Magron, Cécile. “Mesures précises des demi-vies et rapports d’embranchement pour la décroissance β des noyaux miroir 23Mg et 27Si : Precise measurement of half-lives and branching ratios for the mirror β decay of 23Mg and 27Si.” 2016. Web. 15 Apr 2021.
Vancouver:
Magron C. Mesures précises des demi-vies et rapports d’embranchement pour la décroissance β des noyaux miroir 23Mg et 27Si : Precise measurement of half-lives and branching ratios for the mirror β decay of 23Mg and 27Si. [Internet] [Doctoral dissertation]. Bordeaux; 2016. [cited 2021 Apr 15].
Available from: http://www.theses.fr/2016BORD0180.
Council of Science Editors:
Magron C. Mesures précises des demi-vies et rapports d’embranchement pour la décroissance β des noyaux miroir 23Mg et 27Si : Precise measurement of half-lives and branching ratios for the mirror β decay of 23Mg and 27Si. [Doctoral Dissertation]. Bordeaux; 2016. Available from: http://www.theses.fr/2016BORD0180
5.
Finlay, Paul.
High-Precision Half-Life and Branching-Ratio Measurements for the Superallowed Beta+ Emitter 26Alm.
Degree: PhD, Department of Physics, 2012, University of Guelph
URL: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/3510
► High-precision half-life and branching-ratio measurements for the superallowed beta+ emitter 26Alm were performed at the TRIUMF-ISAC radioactive ion beam facility located in Vancouver, Canada. The…
(more)
▼ High-precision half-life and branching-ratio measurements for the
superallowed beta+ emitter 26Alm were performed at the TRIUMF-ISAC radioactive ion beam facility located in Vancouver, Canada. The branching ratio measurement was performed with the 8pi Spectrometer, an array of 20 high-purity germanium detectors, in conjunction with SCEPTAR, a plastic scintillator array used to detect the emitted
beta particles. An upper limit of <= 12 ppm at 90% confidence level was found for the second forbidden
beta +
decay of 26Alm to the first 2+ state at 1809 keV in 26Mg. An inclusive upper limit of <= 15 ppm at 90% confidence level was found when considering all possible non-analogue
beta +/EC
decay branches of 26Alm, resulting in a
superallowed branching ratio of 100.0000+0−0.0015%. The half-life measurement was performed using a 4pi continuous-flow gas proportional counter and fast tape transport system. The resulting value for the 26Alm half-life, T1/2 = 6.34654(76) s, is consistent with, but 2.5 times more precise than, the previous world average, and represents the single most precisely measured half-life of any
superallowed emitting nucleus to date. Combining these results with world-average Q-value measurements yields a
superallowed beta -
decay ft value of 3037.58(60) s, the most precisely determined ft value for any
superallowed emitting nucleus to date. Combined with the small, and precisely quoted, theoretical isospin-symmetry-breaking corrections for this nucleus, the corrected Ft value for 26Alm of 3073.1(12) s is also the most precisely determined for any
superallowed emitter by nearly a factor of two and now rivals the precision of all the other 12 precisely measured
superallowed beta decays combined. The high-precision experimental ft value for 26Alm
superallowed decay reported here provides a new benchmark to refine theoretical models of isospin-symmetry-breaking effects in
superallowed Fermi
beta decays.
Advisors/Committee Members: Svensson, Carl (advisor).
Subjects/Keywords: Nuclear physics; standard model; superallowed beta decay; aluminum; half-life; branching ratio
…transitions following β + decay of
6.1
Superallowed f t and F t values for the 13 well-measured… …laboratories around the world, the precision of superallowed Fermi β-decay halflife measurements… …thesis, which sets a new benchmark for high-precision superallowed Fermi β-decay
half-life… …in
Table 1.1 and demonstrate the high level of activity in superallowed Fermi β-decay… …in superallowed β decay, and the testing of these models against experimental data, thus…
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APA (6th Edition):
Finlay, P. (2012). High-Precision Half-Life and Branching-Ratio Measurements for the Superallowed Beta+ Emitter 26Alm. (Doctoral Dissertation). University of Guelph. Retrieved from https://atrium.lib.uoguelph.ca/xmlui/handle/10214/3510
Chicago Manual of Style (16th Edition):
Finlay, Paul. “High-Precision Half-Life and Branching-Ratio Measurements for the Superallowed Beta+ Emitter 26Alm.” 2012. Doctoral Dissertation, University of Guelph. Accessed April 15, 2021.
https://atrium.lib.uoguelph.ca/xmlui/handle/10214/3510.
MLA Handbook (7th Edition):
Finlay, Paul. “High-Precision Half-Life and Branching-Ratio Measurements for the Superallowed Beta+ Emitter 26Alm.” 2012. Web. 15 Apr 2021.
Vancouver:
Finlay P. High-Precision Half-Life and Branching-Ratio Measurements for the Superallowed Beta+ Emitter 26Alm. [Internet] [Doctoral dissertation]. University of Guelph; 2012. [cited 2021 Apr 15].
Available from: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/3510.
Council of Science Editors:
Finlay P. High-Precision Half-Life and Branching-Ratio Measurements for the Superallowed Beta+ Emitter 26Alm. [Doctoral Dissertation]. University of Guelph; 2012. Available from: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/3510
6.
Leach, Kyle G.
Neutron Transfer Reactions on 64Zn as a Probe for Testing Shell-Model Isospin-Symmetry-Breaking Theory.
Degree: PhD, Department of Physics, 2012, University of Guelph
URL: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/4866
► As part of an ongoing program to study fundamental symmetries in nuclear physics, a thorough investigation into shell-model isospin-symmetry-breaking (ISB) calculation theory has been conducted…
(more)
▼ As part of an ongoing program to study fundamental symmetries in nuclear physics, a thorough investigation into shell-model isospin-symmetry-breaking (ISB) calculation theory has been conducted using direct reactions to observe detailed nuclear-structure information. The work presented in this Thesis focuses on the 62Ga
superallowed beta-
decay system, and consists of two primary experiments; 1) A 64Zn(d,t)63Zn single-neutron transfer reaction, aimed at observing spectroscopic strengths to help guide calculation model-space truncations for the
beta-
decay wave function radial-overlap component of ISB, and 2) A two-neutron 64Zn(p,t)62Zn transfer to search for excited 0+ states in the daughter nucleus of 62Ga. The experiments were performed at the Maier-Leibnitz-Laboratory, on the joint campuses of the Ludwig-Maximilians Universitat and the Technische Universitat Munchen, in Garching, Germany. In total, 162 states in 63Zn were populated from the 64Zn(d,t) reaction, up to an excitation energy of 4.8 MeV, including the observation of 125 new levels, and unique spin/parity assignments for 92 states. As a result, this work provides the most complete picture for low-spin states in 63Zn to date. A comparison of the extracted S values to the predicted shell-model spectroscopic factors shows an overall over-prediction of strength for the 2p3/2 orbital, and a large disagreement for the 1f7/2 orbital above ~3.5 MeV. No significant 1g9/2 strength was observed, leading to the conclusion that the importance of the 1g9/2 orbital for ISB is small. Additionally, 67 states were observed in 62Zn using the two-neutron pickup mechanism, including the observation of five 0+ states. More than 99% of the total 0+ (p,t) cross-section is observed in the ground-state reaction channel, implying a nearly maximal overlap of the wave functions with the two-nucleon transfer operator. The dominance of the ground-state-to-ground-state (p,t) cross section is strikingly similar to the dominance of the
superallowed Fermi
beta-
decay between isobaric-analogue 0+ states. This suggests that the population of excited 0+ states in the (p,t) reaction may reflect the population in the Fermi
decay process, and can be used to guide future experimental and theoretical work. Further discussion of these results as they relate to the ISB correction calculations, and the implications for future theoretical work are presented in this Thesis.
Advisors/Committee Members: Garrett, Paul (advisor), Svensson, Carl (advisor).
Subjects/Keywords: Nuclear Physics; Superallowed beta Decay; Isospin Symmetry Breaking; Fundamental Symmetry; Zinc Nuclear Structure; Shell-Model; Neutron Transfer Reaction
…angular momentum classification for β decays.
. . . . .
32
2.2
Experimental superallowed data… …scheme from
62
Ga β-decay . . . . . . . . . . . . . . . . . . 175
6.20 γ-ray angular… …of β-decay, discussed further in
Chapter 2.
In practice, the above is calculated by… …basis for both one-body (ie. β-decay) and two-body (ie. twonucleon transfer… …f t values for the 13 high precision superallowed decays
35
2.2
Corrected F t values…
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APA (6th Edition):
Leach, K. G. (2012). Neutron Transfer Reactions on 64Zn as a Probe for Testing Shell-Model Isospin-Symmetry-Breaking Theory. (Doctoral Dissertation). University of Guelph. Retrieved from https://atrium.lib.uoguelph.ca/xmlui/handle/10214/4866
Chicago Manual of Style (16th Edition):
Leach, Kyle G. “Neutron Transfer Reactions on 64Zn as a Probe for Testing Shell-Model Isospin-Symmetry-Breaking Theory.” 2012. Doctoral Dissertation, University of Guelph. Accessed April 15, 2021.
https://atrium.lib.uoguelph.ca/xmlui/handle/10214/4866.
MLA Handbook (7th Edition):
Leach, Kyle G. “Neutron Transfer Reactions on 64Zn as a Probe for Testing Shell-Model Isospin-Symmetry-Breaking Theory.” 2012. Web. 15 Apr 2021.
Vancouver:
Leach KG. Neutron Transfer Reactions on 64Zn as a Probe for Testing Shell-Model Isospin-Symmetry-Breaking Theory. [Internet] [Doctoral dissertation]. University of Guelph; 2012. [cited 2021 Apr 15].
Available from: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/4866.
Council of Science Editors:
Leach KG. Neutron Transfer Reactions on 64Zn as a Probe for Testing Shell-Model Isospin-Symmetry-Breaking Theory. [Doctoral Dissertation]. University of Guelph; 2012. Available from: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/4866
7.
Park, Hyo-In.
High-Precision Measurements of the Superallowed Beta+ Decays of 38Ca and 46V.
Degree: PhD, Physics, 2012, Texas A&M University
URL: http://hdl.handle.net/1969.1/ETD-TAMU-2011-08-10182
► As a part of our program to test the unitarity of the Cabibbo-Kobayashi-Maskawa matrix, the decay of the superallowed 0⁺ – > 0⁺ beta emitters…
(more)
▼ As a part of our program to test the unitarity of the Cabibbo-Kobayashi-Maskawa matrix, the
decay of the
superallowed 0⁺ – > 0⁺
beta emitters ³⁸Ca and ⁴⁶V has been studied in this dissertation. For ³⁸Ca, the half-life, 443.88(36) ms, and
superallowed branching ratio, 0.7738(41), have been measured. In our half-life experiment, pure sources of ³⁸Ca were produced and the
decay positrons detected in a high-efficiency 4[pi] proportional gas counter. Since the beta⁺
decay of ³⁸Ca feeds ³⁸K
m, which is itself a
superallowed beta⁺ emitter, the data were analyzed as a linked parent-daughter
decay. Our result for the half-life of ³⁸Ca, with a precision of 0.08%, is a factor of five improvement on the best previous result. The branching-ratio of ³⁸Ca depended on
beta-delayed gamma-ray intensities being measured with a high-purity germanium detector calibrated for absolute efficiency to 0.2% precision. This branching-ratio result represents our first step in bringing the ft value for the
superallowed ³⁸Ca transition into the desired range of 0.1%. With our half-life and
superallowed branching ratio results for ³⁸Ca, we obtain the Ft to be 3072(17) s, in good agreement with the conserved vector current expectation. The half-life of ⁴⁶V has been measured to be 422.66(6) ms, a factor of two more precise than the best previous measurement. Our present result determines the corresponding Ft value to be 3074.5(26) s, which is consistent with the average 𝓕t̅ value of 3072.08(79) s established from the 13 best-known
superallowed transitions. This demonstrates that previously accepted half-lives of ⁴⁶V were correct in their contribution to a precision test of the conserved vector current hypothesis.
Advisors/Committee Members: Hardy, John C. (advisor), Gagliardi, Carl A. (committee member), Tribble, Robert E. (committee member), Yennello, Sherry J. (committee member).
Subjects/Keywords: Superallowed nuclear beta decay; conserved vector current hypothesis; unitarity test of the CKM matrix; half-life; branching ratio; precision measurements
…determination of precise ft values in superallowed Fermi β decay
is provided and the impact it has on… …extracted from
four different sources: nuclear superallowed Fermi β decays, neutron β decay, pion… …exact-symmetry limit. For the superallowed β decay, the Fermi matrix MF is written
as
0 2
|MF… …measurements on both neutron and mirrornuclei β decay. In pion β decay, the beta decay channel is… …decay of the superallowed β + emitters
38
Ca and
46
V has been studied with the
K500…
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APA (6th Edition):
Park, H. (2012). High-Precision Measurements of the Superallowed Beta+ Decays of 38Ca and 46V. (Doctoral Dissertation). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-2011-08-10182
Chicago Manual of Style (16th Edition):
Park, Hyo-In. “High-Precision Measurements of the Superallowed Beta+ Decays of 38Ca and 46V.” 2012. Doctoral Dissertation, Texas A&M University. Accessed April 15, 2021.
http://hdl.handle.net/1969.1/ETD-TAMU-2011-08-10182.
MLA Handbook (7th Edition):
Park, Hyo-In. “High-Precision Measurements of the Superallowed Beta+ Decays of 38Ca and 46V.” 2012. Web. 15 Apr 2021.
Vancouver:
Park H. High-Precision Measurements of the Superallowed Beta+ Decays of 38Ca and 46V. [Internet] [Doctoral dissertation]. Texas A&M University; 2012. [cited 2021 Apr 15].
Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2011-08-10182.
Council of Science Editors:
Park H. High-Precision Measurements of the Superallowed Beta+ Decays of 38Ca and 46V. [Doctoral Dissertation]. Texas A&M University; 2012. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2011-08-10182
8.
Xayavong, Latsamy.
Calculs théoriques de corrections nucléaires aux taux de transitions β super-permises pour les tests du Modèle Standard : Theoretical calculation of nuclear structure corrections to the superallowed Fermi β decay rates for the tests of the Standard Model.
Degree: Docteur es, Astrophysique, plasmas, nucléaire, 2016, Bordeaux
URL: http://www.theses.fr/2016BORD0406
► La conservation du courant faible vectoriel, connue par CVC est une des hypothèses fondamentales du Modèle Standard de l'interaction électrofaible. En revanche, la base théorique…
(more)
▼ La conservation du courant faible vectoriel, connue par CVC est une des hypothèses fondamentales du Modèle Standard de l'interaction électrofaible. En revanche, la base théorique de cette hypothèse est seulement l'analogie avec la théorie de l'interaction électromagnétique et la question de sa validité reste posée. La CVC est vérifiable dans les transitions super-permises, 0+ → 0+, T = 1 car elle prédit que le grandeur Ft (≡ ft corrigée) de ces processus à basse énergie doit être indépendant des noyaux mis en jeu. Si la valeur unique de Ft est trouvée, on peut toute de suite déduire la constante du couplage vectorielle GV , reliée à │Vud│, la norme de l'élément le plus important de la matrice du mélange des quarks de Cabibbo-Kobayashi-Maskawa (CKM). Cet élément de matrice joue un rôle crucial dans le test de l'unitarité de la matrice CKM, une autre hypothèse de base du Modèle Standard. Actuellement, 14 transitions super-permises allant du 10C jusqu'au 74Rb sont expérimentalement connues avec une précision meilleure que 0:1%, Cela fait en sorte que l'accès à la constante de couplage est limité par les corrections théoriques, dues aux effets radiatifs et à la brisure de la symétrie d'isospin. Le principal propos de cette thèse est de ré-examiner la correction due au défaut du recouvrement entre les fonctions d'onde radiales de neutrons et celles de protons (ᵟRO) dans le cadre du modèle en couches. Nos calculs sont basés sur l'expansion des éléments de matrice de Fermi sur les états du noyau intermédiaire, développée précédemment par Towner et Hardy [1]. Cette méthode combine les fonctions d'onde radiales réalistes avec les données spectroscopiques obtenues par un calcul à large échelle, permettant ainsi d'aller au-delà des approches traditionnelles. Nous avons considéré 13 transitions super-permises, y comprises : 22Mg, 26Al, 26Si, 30S, 34Cl, 34Ar, 38K, 38Ca, 46V, 50Mn, 54Co, 62Ga et 66As. Les fonctions d'onde radiales sont déterminées avec un potentiel moyen réaliste, tel que le potentiel phénoménologique de Woods-Saxon (WS) ou le potentiel auto-cohérent de Hartree-Fock (HF) dérivé à partir d'une force effective de Skyrme. Les calculs ont été faits avec des différentes paramétrisations (2 paramétrisations WS et 3 forces de Skyrme) qui nous ont semblés être les meilleures et les plus appropriées à nos besoins. Dans un premier temps, des calculs par une méthode simple, sans prise en compte des états intermédiaires ont été réalisés. Avec le potentiel WS, les valeurs de ᵟRO obtenues sont fortement dépendantes de paramétrisation. Afin de clarifier cet effet, nous avons étudié en détail la sensibilité aux paramètres du potentiel avec une attention toute particulière apportée au terme isovectoriel et au terme coulombien. Cela a permis de mettre en évidence qu'une telle dépendance est entièrement dominée par le comportement isovectoriel du potentiel. Finalement, cette propriété inattendue a été bien maîtrisée par la procédure d'ajustement proposée. (...)
The conservation of the weak vector current, known as CVC is one of…
Advisors/Committee Members: Smirnova, Nadezda (thesis director).
Subjects/Keywords: Tests du Modèle Standard; Hypothèse CVC; Unitarité de la matrice CKM; Transition β super-permise 0+ → 0+; Brisure de la symétrie d'isospin; Correction due au défaut du recouvrement; Modèle en couches; Potentiel de Woods-Saxon; Potentiel auto-cohérent de Hartree-Fock; Standard Model tests; CVC hypothesis; Unitarity of the CKM matrix; Superallowed Fermi β - decay 0+ → 0+; Isospin symmetry breaking; Radial overlap correction; Shell model; Woods-Saxon potential; Self-consistent Hartree-Fock potential
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Xayavong, L. (2016). Calculs théoriques de corrections nucléaires aux taux de transitions β super-permises pour les tests du Modèle Standard : Theoretical calculation of nuclear structure corrections to the superallowed Fermi β decay rates for the tests of the Standard Model. (Doctoral Dissertation). Bordeaux. Retrieved from http://www.theses.fr/2016BORD0406
Chicago Manual of Style (16th Edition):
Xayavong, Latsamy. “Calculs théoriques de corrections nucléaires aux taux de transitions β super-permises pour les tests du Modèle Standard : Theoretical calculation of nuclear structure corrections to the superallowed Fermi β decay rates for the tests of the Standard Model.” 2016. Doctoral Dissertation, Bordeaux. Accessed April 15, 2021.
http://www.theses.fr/2016BORD0406.
MLA Handbook (7th Edition):
Xayavong, Latsamy. “Calculs théoriques de corrections nucléaires aux taux de transitions β super-permises pour les tests du Modèle Standard : Theoretical calculation of nuclear structure corrections to the superallowed Fermi β decay rates for the tests of the Standard Model.” 2016. Web. 15 Apr 2021.
Vancouver:
Xayavong L. Calculs théoriques de corrections nucléaires aux taux de transitions β super-permises pour les tests du Modèle Standard : Theoretical calculation of nuclear structure corrections to the superallowed Fermi β decay rates for the tests of the Standard Model. [Internet] [Doctoral dissertation]. Bordeaux; 2016. [cited 2021 Apr 15].
Available from: http://www.theses.fr/2016BORD0406.
Council of Science Editors:
Xayavong L. Calculs théoriques de corrections nucléaires aux taux de transitions β super-permises pour les tests du Modèle Standard : Theoretical calculation of nuclear structure corrections to the superallowed Fermi β decay rates for the tests of the Standard Model. [Doctoral Dissertation]. Bordeaux; 2016. Available from: http://www.theses.fr/2016BORD0406
. 
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