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Related papers: Superallowed Fermi beta decay

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Superallowed $0^+ \to 0^+$ nuclear beta decay provides a direct measure of the weak vector coupling constant, $\GV$. We survey current world data on the nine accurately determined transitions of this type, which range from the decay of…

Nuclear Theory · Physics 2010-11-23 J. C. Hardy , I. S. Towner

Precision studies of $0^{+} \rightarrow 0^{+}$ superallowed $\beta$ decays provide the necessary data to test stringently the CVC hypothesis. They will also provide a value for the weak vector coupling constant and the $V_{ud}$ quark mixing…

Nuclear Experiment · Physics 2007-05-23 E. Hagberg , J. C. Hardy , V. T. Koslowsky , G. Savard , I. S. Towner

Data on superallowed Fermi beta decay in nuclei are compiled and electromagnetic corrections discussed. Recommended values for the weak vector coupling constant and the leading element of the Cabibbo-Kobayashi-Maskawa mixing matrix are…

Nuclear Theory · Physics 2007-05-23 I. S. Towner , E. Hagberg , J. C. Hardy , V. T. Koslowsky , G. Savard

The measured $ft$-values for superallowed $0^{+} \to 0^{+}$ nuclear $\beta$-decay can be used to obtain the value of the vector coupling constant and thus to test the unitarity of the Cabibbo-Kobayashi-Maskawa matrix. An essential…

Nuclear Theory · Physics 2009-11-07 I. S. Towner , J. C. Hardy

A new critical survey of all world data on superallowed beta decays provides demanding tests of, and tight constraints on, the weak interaction. In confirmation of the conserved vector current (CVC) hypothesis, the vector coupling coupling…

Nuclear Theory · Physics 2010-11-23 J. C. Hardy , I. S. Towner

Nuclear beta decays between (J^pi,T) = (0^+,1) analog states yield the best value for the Vud element of the Cabibbo-Kobayashi-Maskawa matrix. Current world data establish the corrected Ft values of 14 separate superallowed transitions to a…

Nuclear Experiment · Physics 2018-07-04 J. C. Hardy , I. S. Towner

A new critical survey is presented of all half-life, decay-energy and branching-ratio measurements related to 20 0+ to 0+ beta decays. Compared with our last review, there are numerous improvements: First, we have added 27 recently…

Nuclear Experiment · Physics 2009-06-30 J. C. Hardy , I. S. Towner

Measurements of the decay strength of superallowed 0+ to 0+ nuclear beta transitions shed light on the fundamental properties of weak interactions. Because of their impact, such measurements were first reported 60 years ago in the early…

Nuclear Experiment · Physics 2015-06-18 J. C. Hardy , I. S. Towner

Two experiments, (1) a measurement of the superallowed $0^{+} \rightarrow 0^{+}$ branching ratio in $^{10}$C, and (2) a measurement of (or limit on) non-analogue $0^{+} \rightarrow 0^{+}$ branches in $^{38m}$K, $^{46}$V, $^{50}$Mn and…

A complete and critical survey is presented of all half-life, decay-energy and branching-ratio measurements related to 20 superallowed decays; no measurements are ignored, though some are rejected for cause and others updated. A new…

Nuclear Theory · Physics 2014-11-18 J. C. Hardy , I. S. Towner

The Vud element of the Cabibbo-Kobayashi-Maskawa matrix can be determined from several different experimental approaches: either 0+-to-0+ superallowed nuclear beta decays, neutron decay, nuclear mirror decays, or pion beta decay. Currently…

Nuclear Experiment · Physics 2015-09-17 J. C. Hardy , I. S. Towner

A new critical survey is presented of all half-life, decay-energy and branching-ratio measurements related to 20 superallowed 0+ --> 0+ beta decays. Included are 222 individual measurements of comparable precision obtained from 177…

Nuclear Experiment · Physics 2020-10-07 J. C. Hardy , I. S. Towner

The value of the $V_{ud}$ matrix element of the Cabibbo-Kobayashi-Maskawa (CKM) matrix can be derived from nuclear superallowed beta decays, neutron decay, and pion beta decay. We survey current world data for all three. Today, the most…

Nuclear Theory · Physics 2007-05-23 I. S. Towner , J. C. Hardy

There is a well known anomaly between the value of the Fermi decay constant extracted from super-allowed Fermi beta-decay of nuclear isotriplets and that required by unitarity of the Cabibbo-Kobayashi-Maskawa matrix. This discrepancy…

Nuclear Theory · Physics 2010-02-17 Koichi Saito , Anthony W. Thomas

For many decades, the main source of information on the top-left corner element of the Cabibbo-Kobayashi-Maskawa quark mixing matrix $V_{ud}$ were superallowed nuclear beta decays with an impressive 0.01\% precision. This precision, apart…

Nuclear Theory · Physics 2024-04-22 Mikhail Gorchtein , Chien Yeah Seng

The value of the V_{ud} matrix element of the Cabibbo-Kobayashi-Maskawa (CKM) matrix can be derived from nuclear superallowed beta decays, neutron decay, and pion beta decay. We survey current world data for all three. Today, the most…

Nuclear Theory · Physics 2008-11-07 I. S. Towner , J. C. Hardy

We report on a new measurement of the strength of the superallowed 0+->0+ transition in the beta-decay of 10C: 10C(0+,g.s.)->10B(0+,1.74MeV)+e+nu. The experiment was done at the LBNL 88-inch cyclotron using forty seven GAMMASPHERE germanium…

The most precise value of V_{ud}, which is obtained from superallowed nuclear beta decay, leads to a violation of CKM unitarity by 2.2 sigma. Experiments are underway on two continents to test and improve this result through decay studies…

Nuclear Theory · Physics 2009-11-10 J. C. Hardy , I. S. Towner

We perform an ab initio quantum Monte Carlo calculation of the isospin-symmetry-breaking correction $\delta_C$ to the superallowed $\beta$ decay of $^{10}{\rm C}$. Using both phenomenological and chiral nuclear interactions, we evaluate the…

Nuclear Theory · Physics 2026-05-15 Maria Piarulli , R. B. Wiringa , Alessandro Lovato , Garrett B. King , Saori Pastore

We present the first combined analysis of the statistical rate function f in superallowed beta decays with ab initio calculations and data. We focus on C10 to 10B, 14O to 14N and 26mAl to 26Mg, all of which are important channels for the…

Nuclear Theory · Physics 2026-05-15 Bingcheng He , Mikhail Gorchtein , Matthias Heinz , Ben Ohayon , Lucas Platter , Chien-Yeah Seng
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