dorsal/arxiv
View SchemaSuperallowed nuclear beta decays: A critical survey with tests of CVC and the standard model
| Authors | J. C. Hardy, I. S. Towner |
|---|---|
| Categories | |
| ArXiv ID | nucl-th/0412056 |
| URL | https://arxiv.org/abs/nucl-th/0412056 |
| DOI | 10.1103/PhysRevC.71.055501 |
| Journal | Phys.Rev.C71:055501,2005 |
Abstract
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 calculation of the statistical rate function is described and experimental ft values determined. The associated theoretical corrections needed to convert these results into Ft values are discussed, and careful attention is paid to the origin and magnitude of their uncertainties. As an exacting confirmation of the conserved vector current hypothesis, the Ft values are seen to be constant to 3 parts in 10^4. These data are also used to set new limits on any possible scalar interactions or right-hand currents. The average Ft value obtained from the survey, when combined with the muon lifetime, yields the CKM matrix element Vud = 0.9738(4); and the unitarity test on the top row of the matrix becomes |Vud|^2 + |Vus|^2 + |Vub|^2 = 0.9966(14) using the PDG's currently recommended values for Vus and Vub. We discuss the priorities for future theoretical and experimental work with the goal of making the CKM unitarity test more definitive.
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"abstract": "A complete and critical survey is presented of all half-life, decay-energy\nand branching-ratio measurements related to 20 superallowed decays; no\nmeasurements are ignored, though some are rejected for cause and others\nupdated. A new calculation of the statistical rate function is described and\nexperimental ft values determined. The associated theoretical corrections\nneeded to convert these results into Ft values are discussed, and careful\nattention is paid to the origin and magnitude of their uncertainties. As an\nexacting confirmation of the conserved vector current hypothesis, the Ft values\nare seen to be constant to 3 parts in 10^4. These data are also used to set new\nlimits on any possible scalar interactions or right-hand currents. The average\nFt value obtained from the survey, when combined with the muon lifetime, yields\nthe CKM matrix element Vud = 0.9738(4); and the unitarity test on the top row\nof the matrix becomes |Vud|^2 + |Vus|^2 + |Vub|^2 = 0.9966(14) using the PDG\u0027s\ncurrently recommended values for Vus and Vub. We discuss the priorities for\nfuture theoretical and experimental work with the goal of making the CKM\nunitarity test more definitive.",
"arxiv_id": "nucl-th/0412056",
"authors": [
"J. C. Hardy",
"I. S. Towner"
],
"categories": [
"nucl-th",
"hep-ph",
"nucl-ex"
],
"doi": "10.1103/PhysRevC.71.055501",
"journal_ref": "Phys.Rev.C71:055501,2005",
"title": "Superallowed nuclear beta decays: A critical survey with tests of CVC and the standard model",
"url": "https://arxiv.org/abs/nucl-th/0412056"
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