The half-lives of 42Sc, 46V, 50Mn and 54Co

Koslowsky, V.T.; Hagberg, E.; Hardy, J.C.; Savard, G.; Schmeing, H.; Sharma, K. S.; Sun, Xisi

doi:10.1016/s0168-9002(97)01017-6

Cited by 72 publications

(83 citation statements)

References 20 publications

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“…Following dead-time corrections [17,18], the data were fit using a maximum-likelihood technique described in previous works [17][18][19][20]. The fitting routine included a component for the 14 O activity, the 26 Na activity, the 26 Al m activity, and a constant background.…”

Section: β Counting Resultsmentioning

confidence: 99%

“…It is important to note that although all four anomalous runs had negative values of the leading channel removal metric M (decreasing T 1/2 with removal of leading channels), the sign of M is not correlated with the absolute value of T 1/2 at x = 0, as one of the runs had an above-average T 1/2 and three were below average. The remaining 98 dead-time corrected runs were then summed before being fit in order to avoid the known bias resulting from averaging many T 1/2 measurements of lower statistics [20]. A summary of the half-lives from the individual runs is presented in Fig.…”

Section: β Counting Resultsmentioning

confidence: 99%

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High-precision half-life measurements for the superallowed Fermiβ+emitter14O

Laffoley¹,

Svensson²,

Andreoiu³

et al. 2013

Phys. Rev. C

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The half-life of the superallowed Fermi β + emitter 14 O has been determined via simultaneous direct β and γ counting experiments at TRIUMF's Isotope Separator and Accelerator (ISAC) facility. A γ -ray counting measurement was performed by detecting the 2312.6-keV γ rays emitted from an excited state of the daughter 14 N following the implantation of samples at the center of the 8π γ -ray spectrometer, a spherical array of 20 high-purity germanium (HPGe) detectors. A simultaneous β counting experiment was performed using a fast plastic scintillator positioned behind the implantation site with a solid angle coverage of ∼20%. The results, T 1/2 (β) = 70.610 ± 0.030 s and T 1/2 (γ ) = 70.632 ± 0.094 s, form a consistent set and, together with eight previous measurements, establish a new average for the 14 O half-life of T 1/2 = 70.619 ± 0.011 s with a reduced χ 2 of 0.99.

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Section: β Counting Resultsmentioning

confidence: 99%

Section: β Counting Resultsmentioning

confidence: 99%

High-precision half-life measurements for the superallowed Fermiβ+emitter14O

Laffoley¹,

Svensson²,

Andreoiu³

et al. 2013

Phys. Rev. C

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“…The remaining data were corrected cycle-by-cycle for dead-time losses based on the method described in Ref. [14]. The final decay spectrum for each run was then obtained from the sum of the dead-time corrected decay spectra from all accepted cycles in that run.…”

Section: Analysis and Resultsmentioning

confidence: 99%

Precise half-life measurement of the superallowedβ+emitter38Ca

et al. 2011

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“…The beam was implanted under vacuum into the 25-mm-wide aluminized mylar tape for 6-14 s, then allowed to ''cool'' for 26-34 s, reducing the activity of the 26 Na contaminant (T 1=2 ¼ 1:071 28ð25Þ s [17]) to a negligible level. The sample was then moved to the center of the 4 gas counter [18], which was operated within its plateau region between 2700 and 2900 V. The signal from the preamplifier was sent through a discriminator and then split into two data streams. Fixed, nonextendable dead times, chosen to be much longer than the total series dead time of the system, were applied to each stream using two LeCroy 222N nonretriggerable gate-and-delay generators.…”

mentioning

confidence: 99%

“…These cycles represented 0.7% of the counts in the entire data set. The remaining 2008 cycles were dead-time corrected [17,18] and summed for each run.…”

mentioning

confidence: 99%

High-Precision Half-Life Measurement for the Superallowedβ+EmitterAlm26

et al. 2011

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A high-precision half-life measurement for the superallowed þ emitter 26 Al m was performed at the TRIUMF-ISAC radioactive ion beam facility yielding T 1=2 ¼ 6346:54 AE 0:46 stat AE 0:60 syst ms, consistent with, but 2.5 times more precise than, the previous world average. The 26 Al m half-life and ft value, 3037.53(61) s, are now the most precisely determined for any superallowed decay. Combined with recent theoretical corrections for isospin-symmetry-breaking and radiative effects, the corrected F t value for 26 Al m , 3073.0(12) s, sets a new benchmark for the high-precision superallowed Fermi -decay studies used to test the conserved vector current hypothesis and determine the V ud element of the CabibboKobayashi-Maskawa quark mixing matrix. DOI: 10.1103/PhysRevLett.106.032501 PACS numbers: 23.40.Às, 24.80.+y, 27.30.+t High-precision ft values for superallowed Fermi decay transitions between spin J ¼ 0 þ and isospin T ¼ 1 states have proven to be an invaluable probe of the standard model [1]. The validity of the conserved vector current (CVC) hypothesis [2], which states that the vector coupling constant G V is not renormalized in the presence of strong interactions, has been established by the superallowed data at the level of 1:3 Â 10 À4 [3]. Combined with the Fermi coupling constant for purely leptonic decays G F , G V from the superallowed data also currently provides the most precise determination of V ud ¼ G V =G F ¼ 0:974 25ð22Þ [1], by far the most precisely determined element of the Cabibbo-Kobayashi-Maskawa (CKM) matrix relating the quark weak eigenstates to their mass eigenstates. To achieve this precision, the 13 superallowed ft values measured to better than AE0:3% must be corrected to obtain transition-independent F t values [1]:where K is a constant, Á V R is the nucleus-independent component of the radiative correction, 0 R and NS are, respectively, the nuclear-structure-independent and dependent components of the radiative correction for each transition, and C accounts for the breaking of isospin symmetry by Coulomb and charge-dependent nuclear forces [4].Applied to the world superallowed data evaluated in Ref. has led to a reduction of its uncertainty by a factor of 2. The calculations of the nuclear-structure-dependent ISB corrections, on the other hand, have undergone significant revisions in the last decade [4,7], leading to shifts as large as 50% of their own values in some cases, and to a general increase in their individual quoted uncertainties. A further reduction in the uncertainty assigned to Á V R could potentially be achieved via lattice QCD calculations [8], ultimately leading to a value of V ud limited by the nuclear-structure-dependent correction terms. The ISB corrections in superallowed Fermi decays have thus become the focus of intense study in recent years from a variety of theoretical approaches [3,4,[9][10][11][12], as well as semiempirical analysis [13]. Continued development, and refinement, of independent first principles approaches to ISB corrections, and the tes...

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The half-lives of 42Sc, 46V, 50Mn and 54Co

Cited by 72 publications

References 20 publications

High-precision half-life measurements for the superallowed Fermiβ+emitter14O

High-precision half-life measurements for the superallowed Fermiβ+emitter14O

Precise half-life measurement of the superallowedβ+emitter38Ca

High-Precision Half-Life Measurement for the Superallowedβ+EmitterAlm26

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