Measurement of the neutrino asymmetry in the β decay of laser-cooled, polarized 37K

Melconian, D.; Behr, John; Ashery, D.; Aviv, O.; Bricault, P.; Dombsky, M.; Fostner, S.; Gorelov, A.; Gu, S.; Hanemaayer, V.; Jackson, K. P.; Pearson, M. R.; Vollrath, I.

doi:10.1016/j.physletb.2007.04.047

Cited by 56 publications

(60 citation statements)

References 32 publications

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“…This should reduce the uncertainty in the F t value even further. The only 37 K correlation measurement published to date, B ν = −0.755(23) [9], can be used to determine a value for ρ. Using the recoil-order corrections of Holstein [18], we find ρ = −0.560 +24 −29 , where the asymmetric error bars arise from the fact that the uncertainty in B ν is so large that the uncertainty on the extracted value of ρ is not Gaussian.…”

Section: F T-valuementioning

confidence: 99%

“…[7] to determine V ud . The relatively large uncertainty of its contribution was overwhelmingly dominated by the precision of ρ, which was obtained from a single ±3% measurement of the neutrino asymmetry parameter, B ν [9]. The F t value is known much better, to ±0.6% [8], with the largest contribution to its uncertainty being the lifetime of the decay.…”

Section: Introductionmentioning

confidence: 99%

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Precision half-life measurement of theβ+decay ofK37

et al. 2014

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The half-life of 37 K has been measured to be 1.23651(94) s, a value nearly an order of magnitude more precise than the best previously reported. The β + decay of 37 K occurs mainly via a superallowed branch to the ground-state of its T = 1/2 mirror, 37 Ar. This transition has been used recently, together with similar transitions from four other nuclei, as an alternative test of CVC and method for determining V ud , but the precision of its f t value was limited by the relatively large half-life uncertainty. Our result corrects that situation. Another motivation for improving the f t value was to determine the standard-model prediction for the β-decay correlation parameters, which will be compared to those currently being measured by the Trinat collaboration at Triumf. The new f t value, 4605(8) s, is now limited in precision by the 97.99(14)% ground-state branching ratio.

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Section: F T-valuementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Precision half-life measurement of theβ+decay ofK37

et al. 2014

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“…A GEANT4 simulation of the β spectrum is overlayed, with no background subtracted from the data or added to the simulation, demonstrating we have an extremely clean and well-understood system. Analysis of the super-ratio is still in progress, but preliminary analysis of the Dec. 2012 data (filled circles) show a dramatically improved asymmetry compared to the old system (open circles) when B ν was measured [3].…”

Section: Figurementioning

confidence: 99%

“…As expected, the observed asymmetry is large during polarized times and consistent with zero during trapping times. The open circles represent the β asymmetry observed in the old system when we measured the neutrino asymmetry [3] before we added the shake-off electron detector; in that case the asymmetry was significantly attenuated from unpolarized atoms that did not decay from the trap, precluding us from making a precision measurement of A β . Our improved system ensures the β decays occured from trap and already show a much higher asymmetry.…”

Section: Pos(x Lasnpa)010mentioning

confidence: 99%

“…just like the neutron. The TRINAT collaboration has a mature program performing precision β -decay experiments using a magneto-optical trap [1,2,3,4]. We have developed the ability to trap and highly-polarize 37 K using atomic techniques, and have recently taken data for the firstever measurement of the β -asymmetry parameter, A β , from laser-cooled atoms.…”

Section: Introductionmentioning

confidence: 99%

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Precision measurements of beta-decay correlation parameters from trapped atoms and ions

Melconian¹

2014

Proceedings of 10th Latin American Symposium on Nuclear Physics and Applications — PoS(X LASNPA)

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The correlations of the decay products following the β decay of nuclei have a long history of providing a low-energy probe of the fundamental symmetries of our universe. Over half a century ago, the correlation of the electrons following the decay of polarized 60 Co demonstrated that parity is not conserved in weak interactions. Today, the same basic idea continues to be applied to search for physics beyond the standard model: make precision measurements of correlation parameters and look for deviations compared to their standard model predictions. Efforts to measure these parameters to the 0.1% level utilizing atom and ion trapping techniques are described.

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Prospects for precision measurements in nuclear decay in the LHC era

2013

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Precision measurements in nuclear β decay offer a sensitive window to search for new physics beyond the standard electroweak model. Searches for new physics are also a strong motivation for experiments carried out at the high energy frontier. It is instructive to confront results from the low energy and the high energy frontiers in order to look for possible complementarities. This paper reviews the constraints on new physics obtained from nuclear and neutron decays and compares them to those from other semi-leptonic processes and from the LHC. The sensitivity requirements of new precision experiments in β decay, to impact the search for new physics at the light of current and projected LHC results, are updated. Experimental developments in nuclear and neutron β decay are discussed with emphasis on their projected goals to improve the limits on exotic weak couplings.

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Measurement of the neutrino asymmetry in the β decay of laser-cooled, polarized 37K

Cited by 56 publications

References 32 publications

Precision half-life measurement of theβ+decay ofK37

Precision half-life measurement of theβ+decay ofK37

Precision measurements of beta-decay correlation parameters from trapped atoms and ions

Prospects for precision measurements in nuclear decay in the LHC era

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